Charging Battery with Laptop Charger: Dumb or Doable?

[wheelbarrow]

[UPDATE: Please view the messages by sternwake (replies #9 and #15 here) as they dive into the solutions to this question. Thank you all.]

I plan to build a 48v (13s) or 52v (14s) ebike battery pack in the near future. I would prefer to skip buying a cheap ebike charger and instead use USB C power delivery or use my XT60 plug 330 watt 20v laptop charger. I would use a 20v PD trigger for the USB C input. I want to use the chargers I already carry. My questions:

1) What device (if any) can take a constant voltage input and output a CC/CV charging protocol for a 54.6v battery?
2) Could I use the ebike battery to charge drone batteries and a phone with the buck converter + car charger setup shown?

Please ask clarifying questions if you have any. Thank you.

 

[amberwolf]

As long as whatever you are using has "CC" type current limiting (rather than hiccup), where it lowers the voltage until the current is below the set limit, and that limit is below the charging current limit of the pack you're charging, and the max voltage of that is no higher than the max full charge voltage of what you are charging, then you can use "any" hardware you like.

If it has a current limit greater than yoru pack should be charged with, you can damage the pack--if it's high enough over the cells' limitations, it could even start a fire.

If it has only hiccup limiting, it won't provide the CC the pack expects, and voltage will switch on and off completely as fast as the recovery timeout in the charger operates, which the pack doesn't expect. Whether this causes any problems depends on the pack design (mostly the electronics).

If it's voltage is greater than the pack charges to, there is a risk of overcharge if the BMS does not turn off (design flaw, hardware failure, etc).


If all you have is a CV source, you'd need a DC-DC with a CC type current limiter in it, that satisfies the above requirements. It is likely that such a DC-DC will be more expensive than a typical ebike charger, and probably won't come in a box (just bare electronics). It will probably be the same size as an ebike charger of the same power capability, simply because they are the same device in different packaging with slightly different input stages.

But you can poke around for a DC-DC that accepts the input voltage you have available from whatever source you have, and either has a preset output voltage that of your pack, or is adjustable to that voltage. It also needs a preset output current limit that is less than your pack charges at max, or one that is adjustable to that.


If your USB-C supply can be programmed via it's output cable functions to limit it's voltage and current to the pack's limits, *and* it performs CC type limiting, you can directly use it. If you aren't certain that's how it operates, I would recommmend using a device you *are* certain will not damage the pack.

 

[n00b]

As long as whatever you are using has "CC" type current limiting (rather than hiccup), where it lowers the voltage until the current is below the set limit, and that limit is below the charging current limit of the pack you're charging, and the max voltage of that is no higher than the max full charge voltage of what you are charging, then you can use "any" hardware you like.

If it has a current limit greater than yoru pack should be charged with, you can damage the pack--if it's high enough over the cells' limitations, it could even start a fire.

If it has only hiccup limiting, it won't provide the CC the pack expects, and voltage will switch on and off completely as fast as the recovery timeout in the charger operates, which the pack doesn't expect. Whether this causes any problems depends on the pack design (mostly the electronics).

If it's voltage is greater than the pack charges to, there is a risk of overcharge if the BMS does not turn off (design flaw, hardware failure, etc).


If all you have is a CV source, you'd need a DC-DC with a CC type current limiter in it, that satisfies the above requirements. It is likely that such a DC-DC will be more expensive than a typical ebike charger, and probably won't come in a box (just bare electronics). It will probably be the same size as an ebike charger of the same power capability, simply because they are the same device in different packaging with slightly different input stages.

But you can poke around for a DC-DC that accepts the input voltage you have available from whatever source you have, and either has a preset output voltage that of your pack, or is adjustable to that voltage. It also needs a preset output current limit that is less than your pack charges at max, or one that is adjustable to that.

What laptop charger is going to be up to the voltages of e-bike batteries?

 

[amberwolf]

Secondarily, in a separate post to prevent mixing answers, the same applies to charging your packs from the battery. You must convert the pack's essentially unlimited output current at a steadily decreasing voltage to whatever your RC pack charger can take as input.


I don't really understand your diagram; there's a lot of stuff in it and no definite connections between them, some appear to have several destinations or sources and some don't seem to have any? But it looks like you already have unnecessary items and complications, depending on what exactly you intend to do with each piece, and what each thing requires and/or outputs.


Some practical questoins:

if you have a charge source available to charge the ebike pack, why not use that to power the RC charger?

It will save you at least one more device to carry around, and also save you from carrying the ebike pack around (assuming you're not using the ebike to get to the place you're using the RC packs at).

If you *are* using the ebike pack to get around, then you'll be using up range to get back by using it ot recharge your RC packs.

Doing the conversions from one power source to another is very inefficient; you can lose 20-30% or more of the power involved at every conversion.

So, let's say you're using the ebike battery to recharge the RC packs. You'll be converting the ebike voltage down to the RC charger voltage, losing say, 30% of the power. Then you're converting that up to the RC pack voltage, losing say, another 30% of the power.

Efficiency doesnt' really matter when chariging from a wall outlet source, but if you are using the ebike battery to ride with *and* charge from, it does matter, because you are wasting range by doing so.

If you ahve a power source to charge the ebike pack from, then you're not wasting range, but, then you're unnecessarily complicating the setup, and adding equipment to the bundle you're carrying.

 

[Nix Liou]

What laptop charger is going to be up to the voltages of e-bike batteries?

A USB C charger with the EPR 3.2 standard, including AVS, that is capable of 240w, should have a maximum voltage of 48v, at 5 amps, and allow for adjustments of voltage between 15v and 48v in 100mv increments. Perhaps with the right board you could effectively instruct the power brick to do cc/cv for a 36v battery? Would be very jank I think.

 

[wheelbarrow]

As long as whatever you are using has "CC" type current limiting (rather than hiccup), where it lowers the voltage until the current is below the set limit, and that limit is below the charging current limit of the pack you're charging, and the max voltage of that is no higher than the max full charge voltage of what you are charging, then you can use "any" hardware you like.

If it has a current limit greater than yoru pack should be charged with, you can damage the pack--if it's high enough over the cells' limitations, it could even start a fire.

If it has only hiccup limiting, it won't provide the CC the pack expects, and voltage will switch on and off completely as fast as the recovery timeout in the charger operates, which the pack doesn't expect. Whether this causes any problems depends on the pack design (mostly the electronics).

If it's voltage is greater than the pack charges to, there is a risk of overcharge if the BMS does not turn off (design flaw, hardware failure, etc).


If all you have is a CV source, you'd need a DC-DC with a CC type current limiter in it, that satisfies the above requirements. It is likely that such a DC-DC will be more expensive than a typical ebike charger, and probably won't come in a box (just bare electronics). It will probably be the same size as an ebike charger of the same power capability, simply because they are the same device in different packaging with slightly different input stages.

But you can poke around for a DC-DC that accepts the input voltage you have available from whatever source you have, and either has a preset output voltage that of your pack, or is adjustable to that voltage. It also needs a preset output current limit that is less than your pack charges at max, or one that is adjustable to that.


If your USB-C supply can be programmed via it's output cable functions to limit it's voltage and current to the pack's limits, *and* it performs CC type limiting, you can directly use it. If you aren't certain that's how it operates, I would recommmend using a device you *are* certain will not damage the pack.

What a great pile of info, it will take me some time to fully understand each part of it.

Hiccup charging is new to me, I would intend on using a device with the cc/cv method instead. The plan is to never exceed the maximum voltage while charging for the safety reasons you mentioned.

As for a DC-DC converter with a CC type limiter, would you say something like this DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV (two links below) would get the job done? It seems to include the step-up capability to turn my 20v input to the 54.6v I want, and the CC and CV adjustment through two potentiometer dials. You made an excellent point about it being potentially the same cost and size as a dedicated ebike charger.

My USB C charger would be a super basic PD compliant 20v 65W max "chromebook" charger, simply because they can be found anywhere. The goal with a USB C input is to have a backup option even at super slow charging speeds.

I heard a lot of great things about you folks over here at Endless Sphere, and you guys did not disappoint. Thank you for the insightful answers.

Links:

Amazon.com: DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV : Electronics

Amazon.com: DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV : Electronics

www.amazon.com

1800w 40a Cc Cv 10v To 60v Boost Converter 12v ~ 90v Dc Step Up Power Supply Adjustable Module Dc-dc - Buy Dc Dc Step Up Converter 12v 15v 18v 20v 24v 36v 48v 60v 72v 84v,Dc-dc Boost Converter,Dc Dc Converter Module Product on Alibaba.com

1800w 40a Cc Cv 10v To 60v Boost Converter 12v ~ 90v Dc Step Up Power Supply Adjustable Module Dc-dc - Buy Dc Dc Step Up Converter 12v 15v 18v 20v 24v 36v 48v 60v 72v 84v,Dc-dc Boost Converter,Dc Dc Converter Module Product on Alibaba.com

www.alibaba.com

 

[wheelbarrow]

Secondarily, in a separate post to prevent mixing answers, the same applies to charging your packs from the battery. You must convert the pack's essentially unlimited output current at a steadily decreasing voltage to whatever your RC pack charger can take as input.


I don't really understand your diagram; there's a lot of stuff in it and no definite connections between them, some appear to have several destinations or sources and some don't seem to have any? But it looks like you already have unnecessary items and complications, depending on what exactly you intend to do with each piece, and what each thing requires and/or outputs.


Some practical questoins:

if you have a charge source available to charge the ebike pack, why not use that to power the RC charger?

It will save you at least one more device to carry around, and also save you from carrying the ebike pack around (assuming you're not using the ebike to get to the place you're using the RC packs at).

If you *are* using the ebike pack to get around, then you'll be using up range to get back by using it ot recharge your RC packs.

Doing the conversions from one power source to another is very inefficient; you can lose 20-30% or more of the power involved at every conversion.

So, let's say you're using the ebike battery to recharge the RC packs. You'll be converting the ebike voltage down to the RC charger voltage, losing say, 30% of the power. Then you're converting that up to the RC pack voltage, losing say, another 30% of the power.

Efficiency doesnt' really matter when chariging from a wall outlet source, but if you are using the ebike battery to ride with *and* charge from, it does matter, because you are wasting range by doing so.

If you ahve a power source to charge the ebike pack from, then you're not wasting range, but, then you're unnecessarily complicating the setup, and adding equipment to the bundle you're carrying.

I apologize that the diagram is unclear, perhaps two separate images with one for charging the ebike battery and one for charging from the ebike battery would have made things clearer. The general "flow" of the image above is a reverse C shape, starting from the top left, moving right, then down, then left across the page to finish at the bottom left.

The route is: wall outlet charger > CC/CV missing piece > BMS > battery > bike

Then the battery could be disconnected from the bike and used standalone as a small power station, like you see anker, ecoflow, and more make. The route would then be:

Ebike battery BMS > DC-DC step down from 48 to 12v > direct input to drone charger or input to 12v car charger > USB C phone charging or drone charging.

One of the drone chargers can take an AC or DC (XT60 plug) input and the other drone charger can take a DC (XT60 plug) or USB C PD input. It'd be great to make it capable of phone charging as well, which is why I include that USB C car adapter.

I would like to have a large mobile power station to charge drone batteries in the field, away from an AC source. I figure why buy a dedicated EcoFlow-type bank when I would already have a large battery on an ebike just sitting there. My plan is to make the battery removable, so I could take it out and toss it in the car like any power station, but still have the option to ride to a location on that bike a different day and charge with one battery. I hear your range warning; it would be a very short ride distance.

Efficiency is tough. If an AC source were present, I would absolutely run the drone chargers from the wall. As you'd imagine many spots to fly are just out in the wild with no such luxuries. Maybe I could find a ~48 to 12v step-down converter with USB C PD built in (in addition to raw 12v out) to increase efficiency and lower part count. I have heard that the standalone 12v car chargers can be a good route because they're tried and true.

Thanks again.

 

[wheelbarrow]

A USB C charger with the EPR 3.2 standard, including AVS, that is capable of 240w, should have a maximum voltage of 48v, at 5 amps, and allow for adjustments of voltage between 15v and 48v in 100mv increments. Perhaps with the right board you could effectively instruct the power brick to do cc/cv for a 36v battery? Would be very jank I think.

My hope would be to use a cheapo generic chromebook-style charger capable of up to 20v at 65W as a last resort for slow charging. I'd use a USB C PD 20v trigger board (example linked below) to request 20v from the adapter, and feed that constant DC voltage into the CC/CV board we're discussing here.

https://www.amazon.com/JacobsParts-Voltage-Trigger-Module-Type-C/dp/B0C7JMX9HS?th=1

 

[sternwake]

I use CCCV voltage boosters, mostly from 12v lead acid AGM batteries held at 13.6v via an adjustable voltage power supply. Occasionally I power the booster with 5S 18v ridgid power tool batteries or a 7S battery, as a portable charger, to charge my 10S esk8 battery away from home.

These are all limited by their inout amperage. I can get about 9 amps output max from that '1800' watt boister you linked when seeking 42 volts from 12v nominal.
This is the most capable booster I have, well, had.

I had it set to 41 volts and it was at about 3 amps output, when I hooked my anderson powerpole connector to the 31 volt Esk8 battery, maybe its tenth usage.

Sparks started shooting around the three 20 amp fuses and output voltage went to zero. The fuses tested fine. The ebay seller sent a return label and is sending me another unit.

I have treated all my other boosters the same way and all are fine.

Am hoping the new one, when it arrives, does not suffer the same fate. I might use an XT90s antispark connector on its output instead of an Anderson Powerpole.

I did not try the big red 1800 watt booster feeding it from a higher voltage source.

 

[amberwolf]

My hope would be to use a cheapo generic chromebook-style charger capable of up to 20v at 65W

Typically those are not actually chargers in the same sense as an ebike charger. They don't have cc type current limiting, because that is all built into the device the charger plugs into. All of the ones I have seen are just power supplies.

if you connect a discharged battery to them they'll either just shutdown from overcurrent (possibly turning back on and shutting off repeatedly in hiccup mode), blow an internal fuse (or fusible part) or fail from overcurrent if they have no protection against it, etc.

 

[wheelbarrow]

Typically those are not actually chargers in the same sense as an ebike charger. They don't have cc type current limiting, because that is all built into the device the charger plugs into. All of the ones I have seen are just power supplies.

if you connect a discharged battery to them they'll either just shutdown from overcurrent (possibly turning back on and shutting off repeatedly in hiccup mode), blow an internal fuse (or fusible part) or fail from overcurrent if they have no protection against it, etc.

Right, the chromebook charger plugs into the raw DC input CC/CV board that is the subject of this discussion. There is no direct USB C PD to Li-Ion charging, in this thread I am searching for the in-between piece (top right of the image.) A product I've proposed to bridge a DC input (like from USB C) to cc type current limiting is here:

Amazon.com: DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV : Electronics

Amazon.com: DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV : Electronics

www.amazon.com

1800w 40a Cc Cv 10v To 60v Boost Converter 12v ~ 90v Dc Step Up Power Supply Adjustable Module Dc-dc - Buy Dc Dc Step Up Converter 12v 15v 18v 20v 24v 36v 48v 60v 72v 84v,Dc-dc Boost Converter,Dc Dc Converter Module Product on Alibaba.com

1800w 40a Cc Cv 10v To 60v Boost Converter 12v ~ 90v Dc Step Up Power Supply Adjustable Module Dc-dc - Buy Dc Dc Step Up Converter 12v 15v 18v 20v 24v 36v 48v 60v 72v 84v,Dc-dc Boost Converter,Dc Dc Converter Module Product on Alibaba.com

www.alibaba.com

 

[amberwolf]

ah, ok. as long as there is a cc type limiting device at the battery connection end it should work.

i can't say whether any of the specific devices above would work or not, as i haven't used them. i would warn that almsot always such devices have insufficient cooling to actually do the power ratings they specify, and the fans they use tend to be very cheap with no bearings and fail quickly, so i'd recommend replacing the fan with something bigger with a bearing in it. besides, the bigger diameter would also be quieter to move the same air. if you install it to pull air over the heatsink instead of blow air onto it it may also work better, depending on the deisgn of enclosure you build or buy for the unit.

 

[wheelbarrow]

I use CCCV voltage boosters, mostly from 12v lead acid AGM batteries held at 13.6v via an adjustable voltage power supply. Occasionally I power the booster with 5S 18v ridgid power tool batteries or a 7S battery, as a portable charger, to charge my 10S esk8 battery away from home.

These are all limited by their inout amperage. I can get about 9 amps output max from that '1800' watt boister you linked when seeking 42 volts from 12v nominal.
This is the most capable booster I have, well, had.

I had it set to 41 volts and it was at about 3 amps output, when I hooked my anderson powerpole connector to the 31 volt Esk8 battery, maybe its tenth usage.

Sparks started shooting around the three 20 amp fuses and output voltage went to zero. The fuses tested fine. The ebay seller sent a return label and is sending me another unit.

I have treated all my other boosters the same way and all are fine.

Am hoping the new one, when it arrives, does not suffer the same fate. I might use an XT90s antispark connector on its output instead of an Anderson Powerpole.

I did not try the big red 1800 watt booster feeding it from a higher voltage source.

This guy gets it.

By "most capable" I'm guessing you mean on paper? It sounds like your other boosters worked better. Would you mind sharing your current cc/cv boost recommendation? Is it still the kind talked about here, or one of your others?

I'm glad you're getting a replacement on that (hopefully) faulty CC/CV boost converter. Antispark is probably wise, are there XT60 antispark plugs or something similar? XT90 seems overkill when even XT30 would be enough for my charging application.

On the products I linked they state it is a step-up boost board only, not buck/step-down. I take that to mean you can only go up in voltage, you can't feed it 40v and take out 24v cc/cv for example.

"4. The power supply can only be boosted, not depressed, not supplied to the electrical equipment lower than the input voltage, Like charging a 12V battery with a 24V battery, or charging a capacitor. Power to the lED below the input voltage"

Thanks a ton.

 

[wheelbarrow]

ah, ok. as long as there is a cc type limiting device at the battery connection end it should work.

i can't say whether any of the specific devices above would work or not, as i haven't used them. i would warn that almsot always such devices have insufficient cooling to actually do the power ratings they specify, and the fans they use tend to be very cheap with no bearings and fail quickly, so i'd recommend replacing the fan with something bigger with a bearing in it. besides, the bigger diameter would also be quieter to move the same air. if you install it to pull air over the heatsink instead of blow air onto it it may also work better, depending on the deisgn of enclosure you build or buy for the unit.

Makes sense that they'd cheap out on the cooling. One of my drone chargers had the bearing go out on its fan and boy is that a noise you don't want to endure for more than 5 minutes. A larger diameter fan seems wise, as does experimenting with the airflow direction. I'll give those both a try if I go down this route.

 

[sternwake]

These are my 4 voltage boosters/ step up converters.

The red one on top claims 400 watts. It comes up on Amazon or Ebay easily so I wont link it. Its voltage potentiometer is backwards, CCW to increase but the current potentiometer is normal. The voltage trimpot is too touchy above 38 volts, making it difficult to dial in 41.9 volts, and gets more so at higher voltages. A half a degree spin of the pot can easily overshoot by 0.2 volts. Also both potentiometers are located so that if one attaches a 50MM fan across the heatsinks, then one cannot access the potentiometers while the fan is running.

I did burn one of these up exceeding its 12 amp input limit by 50% or so, before I knew better.

The blue booster below it, with the fan, is only rated at 150 watts output, and it can do this reliably, from a 12v input. I did put a 24v fan on its heatsinks and at 12 v and 150 watts output, it still gets pretty hot, as the 24 v fan does not spin very fast on 12v, but it is still going strong, and is by far the most used of my boosters.
It has a third potentiometer which one can tune to have the red LED turn green when amps cross a threshold. I set mine to 0.2 amps. This is a hard one to find. I bought a second one fearing unobtainium status in the future

The 24v fan spins much faster on 5S input voltages, and also handles fully charged 7S voltages(29.4) The unit stays cool at 165 watts output when fed with a 7S battery as the fan is spinning quite fast, and is pretty loud. Blue150 will make a high pitched whining above 150 watts output, So in general I keep it below 150, but it has handled 165 watts output for the full 104 watt hours of my 7s2P battery that was feeding it, more than once.

150blue is my most used booster as I usually bench charge at 100 watts or less, and it has lasted many hundreds of charge cycles being fed from 12v lead acids, 5S power tool and 7S premade esk8 junky batteries.

Amazon.com: DC Boost Converter, Step Up Converter Board 10-32V to 12-60V Voltage Regulator Module Adjustable Voltage Step Up Power Supply Module : Electronics

Buy DC Boost Converter, Step Up Converter Board 10-32V to 12-60V Voltage Regulator Module Adjustable Voltage Step Up Power Supply Module: Power Converters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

This White booster:

Amazon.com: DEVMO 600W Constant Current Boost Converter DC to DC 10V-60V to 12-60V Output Step-up Transformer Module Power Supply Driver Max 10A : Electronics

Buy DEVMO 600W Constant Current Boost Converter DC to DC 10V-60V to 12-60V Output Step-up Transformer Module Power Supply Driver Max 10A: Power Converters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

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claims 600 watts output, but that is unrealistic in the extreme, unless perhaps one is boosting from 58 upto 60 volts. It says 10 amps max input, and has a 15 amp fuse, which I blew around 24 amps input. I soldered a 14 gauge solid wire over the fuse and added my own ATC fuse on the input. Both voltage and amperage potentiometers are backwards. CCW to increase, clockwise to decrease. One needs to attach it to a heatsink, and the xt90 antispark on the input side is necessary as it will have a huge spark without it. 150 blue and 400 red have little sparks hooking it to the input battery. I have pushed this white booster pretty hard with a strong fan blowing over and under it through the deep finned heatsink, and I will not push it much beyond 170 watts at 12v nominal input. On a 7S battery I will allow it to push 250 watts into my 10s Esk8 battery. I have a second white 600 inside my old 7s2P enclosure. The booster sits on a big fat heatsink that the original ESC would have loved. I use an inline Antispark spark Mosfet based switch, and it is good for a few miles of emergency get me home range.

There is another '250' watt white booster available, and I blew this one up immediately as I did not know that the current potentiometer was also CCW to increase and CW to decrease. I thought I had turned it all the way down, but did the opposite. It was cranked to the maximum and the depleted battery was able to suck more than that and pop goes the magic smoke.

I recommend you initially set the voltage unloaded, not hooked to a battery) to just barely above the voltage of the battery you intend to charge, then hook it to the intendee battery, then slowly increase the voltage pot and then see where the current potentiometer is, as if it is dialed all the way up you can blow it up.

You obviously need a way to see amperage and voltage.
My photo above shows two inline wattmeters and I absolutely will not charge without one on the output showing me what is going on. The one on the input side is important too when learning to use it, and not exceed the input amperage limit and it is interesting to wattage on the input vs the output side as well.

The big red 1800 watt booster on the bottom is the same one you aliexpress linked and which I blew up treating it the same way as the other three boosters. I really hope it was just a faulty unit, as for bench charging from 12v nominal, this is the only one I trust above 170 watts output. I don't often charge at this rate but want that ability. I know people have upgraded the Mosfets Diodes and capacitors on these and can get more performance and reliability from them. Big red has nice smooth potentiometers, is more efficient at 150 watts output than all the other boosters, but feeding it 12.2v and ~24 amps iirc, it turns 65 watts into heat, and I could not dial it above 9 amps output.

My BMS is wired for charge only and is only rated at 10 amps, as is my fused charge port, so 9 amps is good enough, but it blew up at 3, so I Don't know. The new one is en route.

There are no XT60 Antispark connectors, much less XT30's.

These are all voltage boosters, step up converters.

While there are Buck/boost, step up/step down converters, I have seen none that have the voltage ranges I need for my battery charging/depleting desires.

I do have a Buck converter, for taking my Esk8's maximum 42 volts and stepping it down to 12v nominal.

This is my second, I blew up the first one when mixing up input and output connectors like a self defeating fool. The first one was able to limit output current to 0.62 amps, but its replacement will not throttle amperage to below 1 amp.

Pardon Our Interruption...

It is pretty big and clunky and I have not used it more than 3 times. I saw some other models on Amazon when looking just now that I would try instead.

I also have a small bucker able to handle 42v input, with adjustable output, but I think it is rated at only 0.5 amps and I have never taken it out of its mylar packaging. I primarily got the bigger bucker more as a way to discharge my DIY Esk8 battery either when me or the Esk8 was injured and I did not want to leave it at 42 volts, the smaller bucker was perhaps for some 12v LED lights, but that has not yet happened.

For charging my Phone on the go I have a single 18650 cell USB A output( thrunite c2) , and a lot of 18650s I can swap into it. I also have 2 small pocket sized 3S1P 18650 packs and a USB-C converter which works from 8 to 23 volts, but can only output 5v at upto 3 amps. I also made a 3s4p Samsung 50E which I can use to power my boosters, but they don't really like it when input voltage falls below 12. The red 400 booster says 10v is the minimum input voltage. I have pushed 600 white from 9.8 volts although it says 12v minimum. It did lower output amperage, but no magic smoke escaped.

The 24v Fan on my 150 watt Blue booster, is a Delta EFB0524MA. It spins at 10v slowly, and spins quite fast and loud at 29.4v.

If never intending to require more than 150 watt, blue 150 would be my recommendation, and if you stay below 80 watts boosting from 12v nominal, the fan is not required.

 

[sternwake]

. Your fix with the external fuse and proper heatsinking is the only way to make those survive.

I certainly had higher hopes for white600. I thought the heatsink that I attached it to, would be adequately sized. I had to look at several different product descriptions before I saw the 10amp input rating, after i blew its 15 amp fuse.

That blown fuse resisted extraction, so I just bridged it with solid 14awg, and added the external fuse holder.

I do have strong 12v computer fans on workbench to blow over and under the booster, through the finned heatsink, and will now push it to 15 amps input from 12v nominal, exceeding its rating by 50%, but this output is still well shy of the 400ish watts I wish to be able to charge at, occasionally. So I ordered big red 1800.

From 7s voltages I have charged as high as 350 watts from white 600, but felt heatsink got too hot, and have settled on 250 watts. In general boosting to 42v from 12v nominal is just hard on the device., and from 3s litbium as voltage, as voltage falls below 12v, it just gets worse, seemingly exponentially.

I do enjoy being able to adjust target voltage and the amperage to get my esk8 battery towards 42v, and most of my charging does not push my boosters close to their limits.

I have thought of what if I am not around any of my 12vdc sources and need to plug into grid and charge. I have thought of boosting from the Dell 19.5v 65 watt power supply or similar, but would rather have a 3+ amp charger designed for 42v output, but would miss the booster's potentiometers.

 

[amberwolf]

One of my drone chargers had the bearing go out on its fan and boy is that a noise you don't want to endure for more than 5 minutes.

You should hear a dremel with a failing bearing...the squawk it makes when it reaches the specific speed that causes it is absolutely horrifying.

My 30+ year old dremel has an analog slide pot for speed on it, so it's worn enough to be touchy and hard to set and keep at a specific speed. If it drops below a certain amount, but above some other speed, the bearing loading changes just enough, without touching the tip to anything, to be a JUMPSCARE right out of a horror movie. I have some jumpscares from a sound library I got with a bunch of others to create more of my music with that have nothing on this sound!

Someday I'll have to find a bearing that fits it and replace that...in the meantime I use an old sewing machine pedal to control the speed instead, and leave the dremel set to max speed. It'll still squawk as it crosses the boundary but then goes quiet(er) again when it's faster than that...it also lets me control the speed while working, which you can't really do with the slider on the side of the dremel itself.

 

[wheelbarrow]

You should hear a dremel with a failing bearing...the squawk it makes when it reaches the specific speed that causes it is absolutely horrifying.

My 30+ year old dremel has an analog slide pot for speed on it, so it's worn enough to be touchy and hard to set and keep at a specific speed. If it drops below a certain amount, but above some other speed, the bearing loading changes just enough, without touching the tip to anything, to be a JUMPSCARE right out of a horror movie. I have some jumpscares from a sound library I got with a bunch of others to create more of my music with that have nothing on this sound!

Someday I'll have to find a bearing that fits it and replace that...in the meantime I use an old sewing machine pedal to control the speed instead, and leave the dremel set to max speed. It'll still squawk as it crosses the boundary but then goes quiet(er) again when it's faster than that...it also lets me control the speed while working, which you can't really do with the slider on the side of the dremel itself.

Sewing machine petal is a great idea, even better than the stock potentiometer. What's the safety risk (if any) of a bad dremel bearing? A little 12v fan will just scream with a failing bearing, but it seems like a 20,000 rpm cutting tool could have a more catastrophic failure.

 

[amberwolf]

Sewing machine petal is a great idea, even better than the stock potentiometer.

I poked around just now and see that some of the modern units apparently come with a speed pedal control already.

What's the safety risk (if any) of a bad dremel bearing? A little 12v fan will just scream with a failing bearing, but it seems like a 20,000 rpm cutting tool could have a more catastrophic failure.

I guess it depends on the failure mode. If it siezes, it'll just stop the shaft and the little rubbery tube inside the casing that connects it to the motor will shear (a mechanical fuse).

If it was spinning a large thing at the user end of the shaft with enough mass and not much structural integrity, seizing would be bad at that speed as it could cause it to fly apart, but this motor isn't powerful enough for that.

If you had a fragile nonreinforced cutting wheel on there it could fracture and fly apart, but for this dremel they have to be tiny, size of a quarter at most, and that sort of disc failure is something that happens anyway just from touching them to the wrong shape of surface that a user must already be prepared for.

The worst thing that might actually happen is the rubber tube fails to shear and the motor overheats and burns out before the user could turn it off.

 

[wheelbarrow]

View attachment 380359

These are my 4 voltage boosters/ step up converters.

The red one on top claims 400 watts. It comes up on Amazon or Ebay easily so I wont link it. Its voltage potentiometer is backwards, CCW to increase but the current potentiometer is normal. The voltage trimpot is too touchy above 38 volts, making it difficult to dial in 41.9 volts, and gets more so at higher voltages. A half a degree spin of the pot can easily overshoot by 0.2 volts. Also both potentiometers are located so that if one attaches a 50MM fan across the heatsinks, then one cannot access the potentiometers while the fan is running.

I did burn one of these up exceeding its 12 amp input limit by 50% or so, before I knew better.

The blue booster below it, with the fan, is only rated at 150 watts output, and it can do this reliably, from a 12v input. I did put a 24v fan on its heatsinks and at 12 v and 150 watts output, it still gets pretty hot, as the 24 v fan does not spin very fast on 12v, but it is still going strong, and is by far the most used of my boosters.
It has a third potentiometer which one can tune to have the red LED turn green when amps cross a threshold. I set mine to 0.2 amps. This is a hard one to find. I bought a second one fearing unobtainium status in the future

The 24v fan spins much faster on 5S input voltages, and also handles fully charged 7S voltages(29.4) The unit stays cool at 165 watts output when fed with a 7S battery as the fan is spinning quite fast, and is pretty loud. Blue150 will make a high pitched whining above 150 watts output, So in general I keep it below 150, but it has handled 165 watts output for the full 104 watt hours of my 7s2P battery that was feeding it, more than once.

150blue is my most used booster as I usually bench charge at 100 watts or less, and it has lasted many hundreds of charge cycles being fed from 12v lead acids, 5S power tool and 7S premade esk8 junky batteries.

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This White booster:

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claims 600 watts output, but that is unrealistic in the extreme, unless perhaps one is boosting from 58 upto 60 volts. It says 10 amps max input, and has a 15 amp fuse, which I blew around 24 amps input. I soldered a 14 gauge solid wire over the fuse and added my own ATC fuse on the input. Both voltage and amperage potentiometers are backwards. CCW to increase, clockwise to decrease. One needs to attach it to a heatsink, and the xt90 antispark on the input side is necessary as it will have a huge spark without it. 150 blue and 400 red have little sparks hooking it to the input battery. I have pushed this white booster pretty hard with a strong fan blowing over and under it through the deep finned heatsink, and I will not push it much beyond 170 watts at 12v nominal input. On a 7S battery I will allow it to push 250 watts into my 10s Esk8 battery. I have a second white 600 inside my old 7s2P enclosure. The booster sits on a big fat heatsink that the original ESC would have loved. I use an inline Antispark spark Mosfet based switch, and it is good for a few miles of emergency get me home range.

There is another '250' watt white booster available, and I blew this one up immediately as I did not know that the current potentiometer was also CCW to increase and CW to decrease. I thought I had turned it all the way down, but did the opposite. It was cranked to the maximum and the depleted battery was able to suck more than that and pop goes the magic smoke.

I recommend you initially set the voltage unloaded, not hooked to a battery) to just barely above the voltage of the battery you intend to charge, then hook it to the intendee battery, then slowly increase the voltage pot and then see where the current potentiometer is, as if it is dialed all the way up you can blow it up.

You obviously need a way to see amperage and voltage.
My photo above shows two inline wattmeters and I absolutely will not charge without one on the output showing me what is going on. The one on the input side is important too when learning to use it, and not exceed the input amperage limit and it is interesting to wattage on the input vs the output side as well.

The big red 1800 watt booster on the bottom is the same one you aliexpress linked and which I blew up treating it the same way as the other three boosters. I really hope it was just a faulty unit, as for bench charging from 12v nominal, this is the only one I trust above 170 watts output. I don't often charge at this rate but want that ability. I know people have upgraded the Mosfets Diodes and capacitors on these and can get more performance and reliability from them. Big red has nice smooth potentiometers, is more efficient at 150 watts output than all the other boosters, but feeding it 12.2v and ~24 amps iirc, it turns 65 watts into heat, and I could not dial it above 9 amps output.

My BMS is wired for charge only and is only rated at 10 amps, as is my fused charge port, so 9 amps is good enough, but it blew up at 3, so I Don't know. The new one is en route.

There are no XT60 Antispark connectors, much less XT30's.

These are all voltage boosters, step up converters.

While there are Buck/boost, step up/step down converters, I have seen none that have the voltage ranges I need for my battery charging/depleting desires.

I do have a Buck converter, for taking my Esk8's maximum 42 volts and stepping it down to 12v nominal.

This is my second, I blew up the first one when mixing up input and output connectors like a self defeating fool. The first one was able to limit output current to 0.62 amps, but its replacement will not throttle amperage to below 1 amp.

Pardon Our Interruption...

It is pretty big and clunky and I have not used it more than 3 times. I saw some other models on Amazon when looking just now that I would try instead.

I also have a small bucker able to handle 42v input, with adjustable output, but I think it is rated at only 0.5 amps and I have never taken it out of its mylar packaging. I primarily got the bigger bucker more as a way to discharge my DIY Esk8 battery either when me or the Esk8 was injured and I did not want to leave it at 42 volts, the smaller bucker was perhaps for some 12v LED lights, but that has not yet happened.

For charging my Phone on the go I have a single 18650 cell USB A output( thrunite c2) , and a lot of 18650s I can swap into it. I also have 2 small pocket sized 3S1P 18650 packs and a USB-C converter which works from 8 to 23 volts, but can only output 5v at upto 3 amps. I also made a 3s4p Samsung 50E which I can use to power my boosters, but they don't really like it when input voltage falls below 12. The red 400 booster says 10v is the minimum input voltage. I have pushed 600 white from 9.8 volts although it says 12v minimum. It did lower output amperage, but no magic smoke escaped.

The 24v Fan on my 150 watt Blue booster, is a Delta EFB0524MA. It spins at 10v slowly, and spins quite fast and loud at 29.4v.

If never intending to require more than 150 watt, blue 150 would be my recommendation, and if you stay below 80 watts boosting from 12v nominal, the fan is not required.

What a phenomenal write-up, thank you.
I have a couple of questions I'd love your input on:

1. Has your replacement 1800W "big red" booster come in yet? If so, what's the verdict; another dud or decent charging?
   
   
2. My power source goes up to 16.5A at 20V (330 Watts), so are the 1,200-1,800 W boards a waste of money and space, or worth it for headroom?
   
   
3. At this time, which of your CC/CV boards would you recommend to boost 20V up to 54.6V? Still the big red, or something smaller like the reliable blue 150W? I'd like to charge my 505 Wh battery in less than 3 hours ideally, but I'm open to changing my expectations if that's unreasonable.
   
   
4. Are your boards smoking because of excessive input amperage? I understand that the output voltage and amps are tuned with potentiometers, but are you regulating the input amps with a fuse or any other method? I'm hoping to grab a decent charging speed with a very healthy chunk of safety margin, but I'm unsure on how to control the raw 16.5 A from my "dumb" charger.
   
   
5. I plan to have a CC/CV charger board like we discuss here connected to my BMS, and a 60-ish volts to 12 or 24 volt buck converter to run lights and a car phone charger. Is it possible to combine the CC/CV charging board and a 12 or 24 volt buck output in one product? The idea would be when not charging from the CC/CV board, it can turn around and take the battery's 48v and turn it into 12-24v. That's not what a "buck/boost" CC/CV charger would do, right? That's just for charging a battery of lower voltage than the source I assume.
   
   
6. I see tons of nice buck/boost CC/CV boards with a nice screen and dial for 36 volts and below. Is the best way to emulate that display an inline wattmeter like you recommend for safety?

Thanks again for the great breakdown above, and if anything in my six questions needs clarification, I'm more than happy to rewrite.

 

[offGridDownUnder]

I have some jumpscares from a sound library I got with a bunch of others to create more of my music

...
Amber, I'm not going to say anything.

 

[amberwolf]

Pardon the OT-ness below:

...
Amber, I'm not going to say anything.

I don't actually use sounds like that, not for that purpose, anyway. (becuase I misuse most things to do what I want to do). There are many sounds that come in the sound libraries I use to create the music that have no musical use I can think of. The jumpscares come from (mostly) horror sound fx libraries, which also have useful musical elements as well as wierd "scary" sound effects--a lot of these effects from such libraries are used in actual movie and tv series soundtracks, so I guess they have a use...just not really for me.

I do sometimes use bits of such sounds as percussive elements, or as attacks at the beginning of a sound, particularly in transitions between musical sections. There are some strange sounds I used in No Bigger Than The Space Of Time whcih is a 5-section (movement?) sci-fi track; most of these are from the Volta library of Sampletraxx****, in the fourth section.

There are some other odd sounds in many of my other tracks; I use a lot of vocal effects, mostly percussively, in the Drywater, Mars series of tracks (music for a never-to-be-made scifi series); that link just goes to the first of eight (so far, there will be more as it is an active current project).


****because I got half their total libraries for a few bucks on a big sale a while back, to use some of the very interesting sounds in certain libraries in my "cinematic" (closest "real" musical category to what I make) music. I've gotten quite a lot of sounds this way in the last couple of years, enabling me to make music I could never have made without them. Well, *I* call it music, anyway.....

 

[sternwake]

What a phenomenal write-up, thank you.
I have a couple of questions I'd love your input on:

1. Has your replacement 1800W "big red" booster come in yet? If so, what's the verdict; another dud or decent charging?
   
   
2. My power source goes up to 16.5A at 20V (330 Watts), so are the 1,200-1,800 W boards a waste of money and space, or worth it for headroom?
   
   
3. At this time, which of your CC/CV boards would you recommend to boost 20V up to 54.6V? Still the big red, or something smaller like the reliable blue 150W? I'd like to charge my 505 Wh battery in less than 3 hours ideally, but I'm open to changing my expectations if that's unreasonable.
   
   
4. Are your boards smoking because of excessive input amperage? I understand that the output voltage and amps are tuned with potentiometers, but are you regulating the input amps with a fuse or any other method? I'm hoping to grab a decent charging speed with a very healthy chunk of safety margin, but I'm unsure on how to control the raw 16.5 A from my "dumb" charger.
   
   
5. I plan to have a CC/CV charger board like we discuss here connected to my BMS, and a 60-ish volts to 12 or 24 volt buck converter to run lights and a car phone charger. Is it possible to combine the CC/CV charging board and a 12 or 24 volt buck output in one product? The idea would be when not charging from the CC/CV board, it can turn around and take the battery's 48v and turn it into 12-24v. That's not what a "buck/boost" CC/CV charger would do, right? That's just for charging a battery of lower voltage than the source I assume.
   
   
6. I see tons of nice buck/boost CC/CV boards with a nice screen and dial for 36 volts and below. Is the best way to emulate that display an inline wattmeter like you recommend for safety?

Thanks again for the great breakdown above, and if anything in my six questions needs clarification, I'm more than happy to rewrite.

1. Yes, My replacement big red 1800 Booster arrived 4 Days ago. I crimped some quality ring terminals onto 10AWG and XT90s, and tried it out.

Happy to report this one was able to exceed the 9 amp output( set to 42 volts output) of the unit which failed, but I stopped dialing it up at 10.03 amps, which is the rating of my charge port and BMS and charge port fuse. Technically my 10s2P of BAK45D can accept 26.4 amps charge current, but I will not be attempting to go there.

10.03 amps output was also 37.27 amps input at 12.34volts, close to the 40 amp input rating. It was turning 70 watts into heat at this output.

I held it there ( 390 watts) for long enough for its fan to kick on, but then backed off the current potentiometer, simply as I had no need to charge at that rate, as I did not need to roll for a few hours.

2. Big red1800's size on my workbench/ charging station is not an issue. At say 100 watts output, it is more efficient than any of my other boosters. Its voltage and current trim pots are less twitchy than any of my other boosters, and I have not used any of my other boosters again yet to charge my esk8. I basically roll once in the late morning and again in late afternoon so two charge cycles a day. The evening charge I slow charge to reach ~ 41 volts by the time I expect to goto bed, and in the morning I will dial it to 41.8 to 42 volts and just crank 200 watts or so output so that by the time I am done with coffee less than 0.2 amps are flowing, and we roll to the parks.


3. Reliable blue 150 is a great booster. I cannot speak to charging with any of my boosters above 42 volts. I will say dialing in the output voltage becomes exponentially harder and harder to do precisely when approaching 40v. I think dialing in 54.6v precisely would be difficult and might too easily drift with temperature on blue 150 red 400 or white 600. Big red 1800 seems less touchy, but I have not tried 54.6v.

4. I blew one red 400 with excessive input amperage. I think I was asking it for 6 amps output, which would have been around 18 amps input, well above the 12 amp rating, So the unit itself cannot be considered at fault. It was user error. Big red 1800, I think was just Faulty as that blew at just 9 amps input, and it is rated at 40.

5. I dont know. I would be guessing. A step down/ buck converter on the battery output would be far different than a boost converter on the input for charging. I'd recommend looking at two different circuits/ products for these purposes instead of one device that might theoretically do both. I have considered a step down converter for 12v lights, but have not yet gone there.

6. I would enjoy a device more accurate and precise than my inline wattmeters to monitor charging current on both sides of my voltage booster/ charger. I owned these wattmeters prior to my getting into Esk8 and exploring beyond 12v nominal voltages. I have played with other hardwired shunted ammeters on 12v nominal, but have not yet sought anything more capable than the very convenient inline wattmeters I have on hand. I know their limitations and inaccuracies account for them and will throw a clampmeter and more precise voltmeter to confirm every so often. I have not explored newer products, and have also not employed a Smart BMS which could display input amperage when charging.

I would love to modify Big red to sit inside a ventilated casing with a large Ammeter and voltmeter and Ah/watthour, columb counter, and have two finger twist potentiometers to dial in output voltage and amperage as desired.
But, that is unlikely to occur anytime soon.
I will just keep using my inline wattmeters and adjust voltage and amperage by the small trimpots. I did acquire a Bourns potentiometer screwdriver to make it a bit safer and easier to dial in those potentiometers to my desires.

I am very reluctant to comment on methods and products I do not have experience with

 

[wheelbarrow]

1. Yes, My replacement big red 1800 Booster arrived 4 Days ago. I crimped some quality ring terminals onto 10AWG and XT90s, and tried it out.

Happy to report this one was able to exceed the 9 amp output( set to 42 volts output) of the unit which failed, but I stopped dialing it up at 10.03 amps, which is the rating of my charge port and BMS and charge port fuse. Technically my 10s2P of BAK45D can accept 26.4 amps charge current, but I will not be attempting to go there.

10.03 amps output was also 37.27 amps input at 12.34volts, close to the 40 amp input rating. It was turning 70 watts into heat at this output.

I held it there ( 390 watts) for long enough for its fan to kick on, but then backed off the current potentiometer, simply as I had no need to charge at that rate, as I did not need to roll for a few hours.

2. Big red1800's size on my workbench/ charging station is not an issue. At say 100 watts output, it is more efficient than any of my other boosters. Its voltage and current trim pots are less twitchy than any of my other boosters, and I have not used any of my other boosters again yet to charge my esk8. I basically roll once in the late morning and again in late afternoon so two charge cycles a day. The evening charge I slow charge to reach ~ 41 volts by the time I expect to goto bed, and in the morning I will dial it to 41.8 to 42 volts and just crank 200 watts or so output so that by the time I am done with coffee less than 0.2 amps are flowing, and we roll to the parks.
View attachment 380821

3. Reliable blue 150 is a great booster. I cannot speak to charging with any of my boosters above 42 volts. I will say dialing in the output voltage becomes exponentially harder and harder to do precisely when approaching 40v. I think dialing in 54.6v precisely would be difficult and might too easily drift with temperature on blue 150 red 400 or white 600. Big red 1800 seems less touchy, but I have not tried 54.6v.

4. I blew one red 400 with excessive input amperage. I think I was asking it for 6 amps output, which would have been around 18 amps input, well above the 12 amp rating, So the unit itself cannot be considered at fault. It was user error. Big red 1800, I think was just Faulty as that blew at just 9 amps input, and it is rated at 40.

5. I dont know. I would be guessing. A step down/ buck converter on the battery output would be far different than a boost converter on the input for charging. I'd recommend looking at two different circuits/ products for these purposes instead of one device that might theoretically do both. I have considered a step down converter for 12v lights, but have not yet gone there.

6. I would enjoy a device more accurate and precise than my inline wattmeters to monitor charging current on both sides of my voltage booster/ charger. I owned these wattmeters prior to my getting into Esk8 and exploring beyond 12v nominal voltages. I have played with other hardwired shunted ammeters on 12v nominal, but have not yet sought anything more capable than the very convenient inline wattmeters I have on hand. I know their limitations and inaccuracies account for them and will throw a clampmeter and more precise voltmeter to confirm every so often. I have not explored newer products, and have also not employed a Smart BMS which could display input amperage when charging.

I would love to modify Big red to sit inside a ventilated casing with a large Ammeter and voltmeter and Ah/watthour, columb counter, and have two finger twist potentiometers to dial in output voltage and amperage as desired.
But, that is unlikely to occur anytime soon.
I will just keep using my inline wattmeters and adjust voltage and amperage by the small trimpots. I did acquire a Bourns potentiometer screwdriver to make it a bit safer and easier to dial in those potentiometers to my desires.

I am very reluctant to comment on methods and products I do not have experience with

Getting clear answers to niche questions feels like booking the last seat on a sold out flight. Thank you again.

I think I was asking it for 6 amps output, which would have been around 18 amps input, well above the 12 amp rating

How can you calculate that? I get that those numbers were for the red 400 and not big red 1800. If my charger DC supply can output 20V 16.5A (330W) would that mean with no losses I could set the CC/CV module to output 54.6V at 6.04A (330W / 54.6V), or is there some other trickery going on? I see now that 40A is the max input amps, and 20A is the max output amps of big red. The cells each call for a .5C charging rate of 1A, times six in series would be 6A normal charging current I hope.

I basically roll once in the late morning and again in late afternoon so two charge cycles a day.

Awesome that you get some serious mileage out of your gear. If I knew in advance I wouldn't cycle my pack in a while, how could I charge or discharge my pack to storage voltage at ~3.75 volts per cell? Would you just unplug halfway through a charging cycle, or run the battery down until hitting the right volts if starting fully charged? Is there a better way?

I feel spoiled from FPV LiPo chargers that let you pick the cell count, C rating, battery chemistry, task type (charge, discharge, storage voltage [which you can specify too], direct DC output, or destroy to 0v), while balancing every cell and displaying the temperature, internal resistance of each cell, mAh in/out, and elapsed time all on a beautiful small LCD. Feels like the stone ages with these CC/CV chargers man, ebikers deserve better.

Do you use a DC breaker/fuse on your bike or battery, even with a BMS? What's your method for determining the adequate amperage?

What a cool build to take the copilot out on a ride.

Safe charging!

 

[sternwake]

I am not really calculating, but observing. My Input wattmeter on Big red 1800 said 12.34v, 37.27amps, 460 watts, the output Wattmeter said 38.8volts, 10.03 amps, 389.1 watts. So basically turning 70 watts into heat, at near its 40 amp input rating.


The more voltage difference and the more amperage one asks of their booster, the less efficient it will be.

Also keep in mind I am pulling voltage from a pair of Lead acid AGMs over about 7 feet of 10AWG cable. So while I am holding these AGMS at 13.7v with an adjustable voltage power supply, there is nearly 1.5v of drop at 37.27 amps.

The power supply itself is capable of 100 amps and 15.5v max, but I have not tried to feed the booster directly from the power supply. I like the idea of the battery in the middle reducing voltage ripple, but feeding big red 15.5v would certainly be better than 12.23v.

Your 19.5v power supply might not be able to maintain 19.5v at its maximum rated current, and there will be some degree of voltage drop from the power supply through the cabling and connectors to the booster's input.


One more thing to keep in mind is my 10.03 amps output was at 38.9 volts. I had the booster set for 42 volts, when not connected to the battery, but 10 amps charging current was only able to bring the voltage to 38.9, when I read my wattmeter. As it charges, voltage climbs towards 42 and thus wattage will rise towards 420. This is still the constant current phase, and once it reaches 42 volts then it is the constant voltage phase, and less and less amperage will be required from the booster to maintain constant 42 volts.

When amps taper to a specified amount at this peak target voltage, then the battery can be considered fully charged. Usually it is around 0.1 amps per cell, so in my case when my 10S2P of BAK 45D has amps taper to 0.2 at 42 volts, ( assuming perfect cell balance) I should remove the charging source. If I were to leave it connected AMPS will taper down below the resolution of my Wattmeter, and this is abusive to the cell for no benefit, Ignoring the balancing function of BMS's.

I have had several 7S chargers not only exceed 29.4v, but also they never shut off. They will bring the battery to 30.2v and the red light turns from red to green when amps taper from 0.32 to 0.31. Leaving this charger plugged in overnight is effectively overcharging the batteries, which is of course dangerous and bad for their longevity. I think it is wise for everybody to use a wattmeter inline to see what their charging source is actually doing.
I despise the red light green light mindset from my Lead acid 12v days and the chargers marketing claims, and the charger fanboy's astounding ignorance about charger behavior and Lead acid battery's requirements in order to reacht true full charge and achieve respectable longevity in deep cycle applications.

So I believe it is critical to be able to measure the actual output of the charging source, and to remove it at the correct time.

What I am doing is 100% manual charging, and there is significant room for the human error factor to materialize.

If you plan on charging with a voltage booster, keep in mind there is nothing automatic about this.

The BMS, unless it sees 4.25v on one or more parallel group, is not going to disconnect the battery from the charging source. If it has a temperature sensor, it might not disconnect until too late.
This is not a set it and forget it method of charging.
It requires no less than an ammeter and voltmeter on the output and the ability to dial in the correct voltage and the ability to disconnect the charger before amps taper to less than 0.1 per cell within the P group, but double check the specs of the cell you are using.

My Dumb Daly BMS says it starts passively balancing with super low currents, at 4.18 volts, so When I want to balance, I approach 41.8v slowly. It is only when I am trying to balance when I will allow amps to taper to less than 0.2. When I see amps taper to 0.00 at 41.8v, I will disconnect charger from battery, adjust output voltage to 4.185, and then reattach booster to the battery. Amps will usually start around 0.95( unles I have current trim pot dialed way lower than this) or so and immediately start tapering again.

When it reads 0.00amps I disconnect, set to 4.19, reconnect and watch amps taper towards zero again. then 4.195, then 4.20. In theory this super low and slow charging will allow the lowest parallel groups to catch upto the highest.

My wattmeter starts reading a bit lower than actual at around 0.2 amps and will not read current below 0.05 amps, but I have had wattmeters start reading low at 0.5 amps, and read 0.00 when 0.25 amps were still flowing. So it really requires one to verify the wattmeter's accuracy before trusting it. I have 5 wattmeters currently, and trust two of them to be very close to actual on voltage and amperage. The others I have taped warnings onto them, like 'reads 0.2v low at 42 volts' and do not trust amperage readings below 0.4 and disregard Watthour figure completely as insane.

I really wish I could recommend a specific wattmeter as being more accurate than others, but there are so many clones, it is really luck of the draw, and even when I thought I found a good one and ordered another from the same seller, it was not as accurate, So One really needs to verify and confirm before trusting. The two that I trust right now, are no longer sold, and they have issues like occassionally freezing up, and they have a KWH figure that is just insanely inaccurate. Two more of my most recently acquired, do not store peak wattage or amperage or minimum voltage for more than minute, and read 0.2v high at 40v and amps they read too low and nothing at all below 0.4.


If I cannot be there to disconnect the booster when the battery will reach full, I set the max voltage to well less than 42 volts, and amps will taper to well below 0.2, and this is not ideal but it is not nearly as damaging to the cells as holding them at 4.2v while amps taper to zero.

If I drain my battery to well less than storage voltage, and know I am not going to be riding for a while, I would simply set my booster's output voltage to 34.7v, and let it go until amps taper to ~0.2. If I let it taper to 0.00 then when I remove the charger the battery stays at 34.7v. If I remove it while it is still accepting 0.2 amps at 34.7v, the battery voltage will fall to around 34.59v within a few hours. I know Lipo storage voltages are generally higher but I will choose 3.3 to 3.5volts storage voltage for Liion cells, and maybee lower if I know there is little self discharge and the BMS and ESC are completely disconnected. But I only have one lithium battery not in regular use, and its self discharge is very very low even with Dumb Daly BMS still connected.

If my battery is at 42v, and I cannot ride it to discharge it down to storage voltage, then I use my Voltage Bucker/ step down converter and power a 12v Fan or LEDS or Both, until I am at the desired storage voltage, but this is also a manual process, through the BMS.

In Esk8, having the BMS wired for discharge can be dangerous, as if one is accelerating and a cell group falls below 2.8v, and it cuts power, the rider can streetface, be thrown from the board. With No physical brakes, having the BMS cut power effectively means No brakes, which can also be very dangerous. So the ESCs are generally fed directly from battery, not through the BMS. The ESC performs the low voltage cut off with a soft cut at say 3.1 volt per cells and a hard cut at 3.0, and those with Vesc set their desired soft and hard cut voltages.

I do not have a fuse on My battery to ESC feed, but probably should.

I do Fuse my charge port, and I have wired fuses on both sides of some smaller 5 amp boosters or buckers, even though they usually have input side fuses built into the booster. Big red 1800 I am just trusting its built in fuses, but it would be wise to install a 10 amp 58v rated fuse on its output and a redundant 40 amp fuse on its input.