Quick Meanwell charging question

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cthetoy   100 µW

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Quick Meanwell charging question

Post by cthetoy » Sep 13 2018 10:14am

I have several ELN-60-48D from my DIY reef LED lighting a few years ago that I am not using. I want to slow charge 13s 48v battery at 1Ah. The max voltage I was able to get was 53.2 volts. I want to undercharge my 48v battery pack to 52 volts keeping it withing the 80%-90% charged range for longevity.

Do I just adjust the voltage to 52 volts, adjust Ah around 1.0Ah (Max is 1.3Ah according to the specs) plug in and charge? Sounds too easy but wanted to make sure. Ill set a timer to remind myself, I don't mind waiting for 10 hours to charge at 1aH as I am doing this at work.

I was a dunce in math. What is 80% to 90% target charge for a 48v 13s battery which tops at 54.4 Volts?

ScooterMan101   10 MW

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Re: Quick Meanwell charging question

Post by ScooterMan101 » Sep 13 2018 12:56pm

53.2 volts is only 4.09 per cell . Well within that 80-90% range .

BTW I have been told by the long time Hobby Flyers that use Lipo, which does not have a BMS so they need more close monitoring compared to if you have 18650's with a BMS .... that your batteries will last a long time even if you charge to 4.2 V per cell ... as long as you use the battery right after charging.

It looks like you would be using the bike/battery to get back home after work ?
if so
then you can charge the battery to more than 53.2 volts, but since your meanwell's only charge up to that voltage and since they only charge up to 1.3 amp then go ahead and use the full 1.3 amps and charge to 53.2 .

With those charging numbers from the Mean Well ,

You need to pay more attention to how far down you Discharge the battery. Best to only use the Battery down to 48.9 Volts which equals 3.73 volts per cell.
My first conversion ... Sold

viewtopic.php?f=3&t=71378&p=1077497&hil ... 1#p1077497

It's 2018 already, ( now 2019 ) lets get some real , improved e-bike / e-velomobile / e-motorcycle designs .

cthetoy   100 µW

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Re: Quick Meanwell charging question

Post by cthetoy » Sep 13 2018 1:49pm

Thanks Scooterman101 for the quick response. I'm using the bike right away after charging at work. The current charger is 3A 54.6V. Meanwell I will set it max it will go which is 53.2. The battery does have a BMS built in as the charger that came with it will turn off when it reaches 54.6 V.
You mentioned use battery down to 48.9 volts. Why so high? Im reading that the lowest I could go is 36v on a 48v battery. Not sure if 36v is 0% or 20% of battery life left as they said never go below 20% and charge to 90%. What percentage is 48.9 or 3.73V per cell.
ScooterMan101 wrote:
Sep 13 2018 12:56pm
53.2 volts is only 4.09 per cell . Well within that 80-90% range .

BTW I have been told by the long time Hobby Flyers that use Lipo, which does not have a BMS so they need more close monitoring compared to if you have 18650's with a BMS .... that your batteries will last a long time even if you charge to 4.2 V per cell ... as long as you use the battery right after charging.

It looks like you would be using the bike/battery to get back home after work ?
if so
then you can charge the battery to more than 53.2 volts, but since your meanwell's only charge up to that voltage and since they only charge up to 1.3 amp then go ahead and use the full 1.3 amps and charge to 53.2 .

With those charging numbers from the Mean Well ,

You need to pay more attention to how far down you Discharge the battery. Best to only use the Battery down to 48.9 Volts which equals 3.73 volts per cell.

markz   100 GW

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Re: Quick Meanwell charging question

Post by markz » Sep 13 2018 2:49pm

There MAY be little need for a BMS in certain situations. Yes no typo there.

For example if you dont stress the pack too much
- DON'T use up the entire Ah of the pack - The shallower the usage the better!

- DON'T stress the pack by using too much DISCHAGE - If you have a pack that can do 10A per Parallel on a 10S5P, sure you can use 50A, but using 25 or 30 or 35A is healthier.

- Some chemistries stay balanced better. Like the Makita Lithium Ion (LiMn) packs.

What I do is open up my pack every so often, especially if I notice a drop in total distance, or do the same distance and the voltage is drastically different.

I could, if I so choose. Use two RC chargers that can do 6S on a 10S or 13S pack, if I had the balance/sense wires on.
Then on evening, charge pack up to say 40V on a 10S which at max charge is 42V, then hook up RC balance chargers for the last bit. Now mind you my pack currently is 10S4P, I'd have to do 4 cycles of charging, meaning at 5pm-6pm I'd get only 1P done, and have to do the other 3P.

Overall, it is better to use a BMS and a good one. Bestech has some but their MOQ is 2, have to buy 2 minimum. But with BMS just plug in 2 main pos and neg and the BMS splits it up and balances for you, easy!


ScooterMan101 wrote:
Sep 13 2018 12:56pm
18650's with a BMS
Last edited by markz on Sep 13 2018 5:59pm, edited 1 time in total.

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flippy   1 MW

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Re: Quick Meanwell charging question

Post by flippy » Sep 13 2018 4:10pm

13*4.05=52.65V

and yes, it is that easy. the slower and lower you charge the longer the pack lives.

i dont know how the ELN series behaves at top voltage. i only know the ELG and HLG dont go beyond their set voltage limit.
Lithium beats liquid dinosaurs.

ScooterMan101   10 MW

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Re: Quick Meanwell charging question

Post by ScooterMan101 » Sep 13 2018 4:25pm

I use Lipo's, so I must series together two 6s packs for a 12s pack, or , two 7s packs for a 14s pack .
( You have a 13s pack )

When I got my last shipment of two 7s lipo's I tested them with a Cellmaster 7 Digital Battery Capacity Checker.
Each cell was around 3.75 volts , which the Cellmaster says is 14% charge. ( Batteries have to be shipped mostly discharged for safety reasons )
So
3.73 Volts per cell is somewhere around 11-13 % capacity left .
I took the 3.75 volt per cell and X it by 13 for your 48 volt pack, and it comes to that 48.9 volts.

Some people discharge their batteries lower,
However
I like to go down to 52 volts at the lowest with my 14s packs to give them longer life.
Which is about 3.71 volts per cell average.


cthetoy wrote:
Sep 13 2018 1:49pm

You mentioned use battery down to 48.9 volts. Why so high? Im reading that the lowest I could go is 36v on a 48v battery. Not sure if 36v is 0% or 20% of battery life left as they said never go below 20% and charge to 90%. What percentage is 48.9 or 3.73V per cell.
My first conversion ... Sold

viewtopic.php?f=3&t=71378&p=1077497&hil ... 1#p1077497

It's 2018 already, ( now 2019 ) lets get some real , improved e-bike / e-velomobile / e-motorcycle designs .

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MadRhino   100 GW

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Re: Quick Meanwell charging question

Post by MadRhino » Sep 13 2018 4:41pm

cthetoy wrote:
Sep 13 2018 1:49pm
...
You mentioned use battery down to 48.9 volts. Why so high? Im reading that the lowest I could go is 36v on a 48v battery.
In your initial post you don’t say what battery chemistry. Yet you say 13s and by the voltage, the simple logic is telling LiCo chemistry (either RC Lipo or round cells).
LiCo chemistry cells are degrading very fast from 3.7v and it is important to avoid discharging any of your cells to this critic voltage.
They don’t keep balance when you discharge them sub 3.7, because the slightest difference in resistance or capacity is exponentially growing from this point down. Their C rate is getting much lower and eventually, they start to swell.

You can discharge a 48v battery to 36v with most other chemistries.

Then, and the most important, RC lipo should never be left charging without immediate supervision unless it is in a 100% fireproof enclosed area. Slow charging is making people neglect this important Lipo maintenance rule.
Make it fool-proof, and I will make a better fool.
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markz   100 GW

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Re: Quick Meanwell charging question

Post by markz » Sep 13 2018 6:08pm

MadRhino wrote:
Sep 13 2018 4:41pm
Then, and the most important, RC lipo should never be left charging without immediate supervision unless it is in a 100% fireproof enclosed area. Slow charging is making people neglect this important Lipo maintenance rule.
LiPo's
- Some people have mentioned using a scrap BBQ a ways away from anything that can burn.

- Others mention using an army ammo box, but leaving the latch loosely on, so the smoke can escape. So leaving a gap you can see, but still latched.

- Fire safe bags from Hobby King I would not trust.
- Fire safe bags from any RC store, I would not trust.
- The only fire bags I would trust would be a product the Fire Department uses, what those are someone may know. They must exist, but for that amount of energy in a LiPo battery ziplock bag pouch, may not be appropriate or safe.

Steel is safe!

Them cheap RC chargers, are 80W or 50W and takes forever to balance, oh I do remember doing that before my LiPo's did their fireworks show, thankfully I baby sat them, heard the popping and knew, 0.4C was not slow enough, may have been 0.25C. Either way having no LVC of any sort is dangerous, human nature is to throttle on. I can't remember if I had them audible rc alarms or not. But I ran outta juice 10 blocks from home, no lvc, throttled on, fireworks.

AHicks   1 kW

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Re: Quick Meanwell charging question

Post by AHicks » Sep 13 2018 7:56pm

cthetoy wrote:
Sep 13 2018 11:43am
I have several ELN-60-48D from my DIY reef LED lighting a few years ago that I am not using. I want to slow charge 13s 48v battery at 1Ah. The max voltage I was able to get was 53.2 volts. I want to undercharge my 48v battery pack to 52 volts keeping it withing the 80%-90% charged range for longevity.

Do I just adjust the voltage to 52 volts, adjust Ah around 1.0Ah (Max is 1.3Ah according to the specs) plug in and charge? Sounds too easy but wanted to make sure. Ill set a timer to remind myself, I don't mind waiting for 10 hours to charge at 1aH as I am doing this at work.

I was a dunce in math. What is 80% to 90% target charge for a 48v 13s battery which tops at 54.4 Volts?
My take, if I'm following this correctly, one possible reason you are only able to get to 53.2 volts is that you are not balance charging, and you have some low cells somewhere in that pack. 53.2/13= 4.09 average charge across all the batteries in that pack. If you are not balance charging, some cells are very likely above that number, while several more are (well) under. It's OK to charge like that on occasion, but ultimate health will have all cells with an equal charge, at something very close to 4.2 volts when fully charged. That's what we shoot for in RC anyway. At the other end, 3.0v would be our drop dead do not go any lower voltage (for long battery life anyway).

I have no issue with wanting to use 80-90% of a pack's capacity, I'm just not sure how you could do that consistently - with some assurance the cells will remain balanced (or nearly so).

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Re: Quick Meanwell charging question

Post by dustNbone » Sep 14 2018 12:37am

I think the power supply he is using to charge tops out at 53.2V.

They should stay reasonably balanced on their own as long as they're kept from deep discharge (under 3.7V or so), and discharged well below their C ratings.

Personally I'd want an easy way to monitor the cell voltages, just something to glance at when the charge (and discharge) is complete to see if anythings going awry. It's very unlikely that anythings going to stray too far over the course of a single cycle, and undercharging slightly does offer some headroom.

AHicks   1 kW

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Re: Quick Meanwell charging question

Post by AHicks » Sep 14 2018 8:25am

I'd really like to know more about this, from a practical standpoint.

This leaves me wondering about the suggestion to not discharge below 3.7v (48.1v in a 13 cell pack). If we were able (and willing) to charge the cells to 4.2v (52v for the pack), this would leave us with a fairly short range, no?

In the interest of maximizing battery life, if we were able to cut the charge off at 4.1v, and set up our LVC at 3.7, we'd have a battery that would last a long time, but how far could we ride it - as compared to a battery that was run from 4.2 - 3.0 or maybe3.3v?

Also, regarding maintaining individual battery cell to cell balance without taking the pack to full charge (4.2v per cell). This is not a concern? How does the BMS system play into this (assuming you have one)? What about packs not equipped with a BMS?

Thanks!

cthetoy   100 µW

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Re: Quick Meanwell charging question

Post by cthetoy » Sep 14 2018 9:34am

So what is worse on your suggested voltage range on a 13s 48v?

You recommended between 48.9 to around 53.5. If thats the case then I will need to charge daily for my commute to work. If I can use the range from 42v to 53.5 then I can charge every other day. What best for the battery? Charge daily within the range or charge battery every other day?

Is it worse to go continuously to 30% battery and charge to 90% or worse to got 40% battery left and charge up to 100% ?

AHicks   1 kW

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Re: Quick Meanwell charging question

Post by AHicks » Sep 14 2018 10:40am

All I know for sure is the 48v controllers I've bought have the LVC set for 40v. That's 3.07v per cell. They can be configured to shut off a little higher.

In radio control, common practice is to use 3.0v as a max discharge, but many do use slightly higher in the interest of keeping happy batteries.

markz   100 GW

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Re: Quick Meanwell charging question

Post by markz » Sep 14 2018 12:52pm

AHicks wrote:
Sep 14 2018 10:40am
LVC
For anyone interested.....

LVC's can be changed by unsoldering the right dab of solder and soldering in a dab of solder at the right location.
Sometimes you get lucky and on the printed circuit board there are ingrained labels like 48V, 60V, 72V.
This method also works great if you want a custom LVC by using a resistor or variable resistor/potentiometer.
Instead of 40V as the LVC, you could modify it and achieve 42V or 38V.
Not much work or tools required either. A $5 soldering iron, a small 0.6oz package of solder $3, solder wick $3 (wick is not absolutely required but good to have) and for custom lvc's a 25 turn 15-20kohm pot for $3, that value may change from controller to controller, but its probably unlikely.

Here is a thread
viewtopic.php?f=3&t=95568&p=1399732&hil ... c#p1399650

dustNbone   10 kW

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Re: Quick Meanwell charging question

Post by dustNbone » Sep 14 2018 1:01pm

cthetoy wrote:
Sep 14 2018 9:34am
So what is worse on your suggested voltage range on a 13s 48v?

You recommended between 48.9 to around 53.5. If thats the case then I will need to charge daily for my commute to work. If I can use the range from 42v to 53.5 then I can charge every other day. What best for the battery? Charge daily within the range or charge battery every other day?

Is it worse to go continuously to 30% battery and charge to 90% or worse to got 40% battery left and charge up to 100% ?
You're better off (battery life wise) charging more often through a smaller range than fewer charges through a larger range. Especially if you're not planning to use a BMS, you need to leave a bit of headroom to avoid accidentally overcharging any cells.

If you look at a discharge graph for RC LiPo, you see that 3.7V is well beyond half dead, 3.6V is quite close to dead. There's very little energy left in them at this point, and squeezing that last bit from them will cause them to imbalance.

Image

Notice how much the cell voltages diverge from eachother near the end of the discharge.

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MadRhino   100 GW

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Re: Quick Meanwell charging question

Post by MadRhino » Sep 14 2018 2:06pm

RC lipo does stand much better being overcharged to 4.25, than being discharged to 3.5. Low voltage is wearing them very fast, while high voltage has little impact as long as you are riding right after charging. The important monitoring of RC lipo that is neglected is heat. We all monitor voltage, those with concern monitor individual cells, but few are monitoring heat. Temp is telling you the moment your cells are suffering damage, voltage doesn’t. The RC lipo battery pack can be perfectly within ‘safe’ voltage, yet suffering damage because they are delivering too much current for too long time, temp is telling you. Bulk charging, as long as they are cool you don’t need to worry, temp will tell you when you are charging too fast or too high. Low resistance cells can be charged very fast. I sometimes charge my 24s 16Ah pack by the time I smoke a cigarette. I stop charging when temp start raising, most of the time they are above 100v already.

You won’t burn RC lipo if you are with them watching. Even if you are not watching, they start to smell long enough before catching fire. But, when you are not there with them, anything can happen. You might believe slow charging can save your cells and your house, or trust a BMS to replace your immediate presence... Some day, anytime, they can prove you wrong. Be there with them when charging or discharging, rest them at storage voltage unplugged off anything, are the only real safety. Even then, there is still a risk. Some have had lipo fires without breaking the rules, because something fell and punctured them, or a mouse chewed a corner off a brick.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

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