new eZip motor

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As the Hub Motor Turns and the LiPo Fire Burns. 18650 - 6S pack. Low power but functional and totally stealth.

Google maps tell me it was 0.6 miles to the grocery store and 1.2 miles on the return trip going a different way. That plus the Wall-Mart parking lot I went approx. 2 miles with the new pack. Bottom picture shows voltage upon return.

Power was low. 10 mph 12 if lucky. It is in a low pedal gear but can pedal a little faster than the motor will go on the flat. I have to pedal with the heels of my feet as there is not much room with the fake saddle bags but I will get used to it.

On the way back I passed two or three police about 10 feet away. I did not notice them until I passed them. It was a police van and squad car out in front of Wall-Mart. Two officers were standing by the entrance and one was looking right at me. :lol:

I think they were there for a shoplifter maybe, My motor was running and I went passed also pedaling. There was a little noise coming from my motor as it is not nearly as quiet as the geared hub motor However their engines were running so I don't think they noticed.

Without pedal assist it wont even make it up a small hill and to get more range two 6S packs in series would be better. however for groceries and Wall-Mart I think I can live with it the way it is for now. I had issues with the chain coming loose before and it would be a pain in the a s s to have to pedal it any distance.

Also with the way I hid the motor I would need to take out a screw and cut a few zip ties to get to the bolts. I checked it when I got back and the chain was tight. I will recharge the pack and try to do a video in a few days in the parking lot. Thanks.

LC out.
 

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I still have the 24 volt Currie SLA charger.

I was wondering if it would be ok to charge the 6S pack with the LG 18650 cells with the 24 volt SLA charger ?

Please let me know. Thanks.

LC out.
 
latecurtis said:
I still have the 24 volt Currie SLA charger.
I was wondering if it would be ok to charge the 6S pack with the LG 18650 cells with the 24 volt SLA charger ?
Don't know ... hmm ...
What voltage does a 24V SLA charger charge at?
What voltage does a 6s Lithium charger charge at?

Well a 6s Li-ion should be charged to 24.6V - 25.2V (4.10-4.20V per cell).
SLA 24V charger charges at ±28V or 4.67V per Lithium cell.
I'm not sure, but cells may likely vent or leak or explode.

I really wish you would use a little thought or common sense, or try being sober, when asking questions!
 
I really wish you would use a little thought or common sense, or try being sober, when asking questions!

Thank you DA.

The fact is though I asked the question yesterday and did not even drink last night which is rare for me. Usually I drink three of four cans of 25 oz beer which is about a 6 pack.

I usually eat two regular meals daily or one large meal before drinking and take my blood pressure pills at least a couple hours before my first beer. The exception is when I go downtown to see my friend and drink 8 to 10 - 12 oz Budweisers and when I get home 2 or 3 cans of 25 oz beer. I do weigh about 240 to 250 pounds though so is not an excessive amount for me vs. a 140 to 160 lb person.

I really am NOT a big alcoholic. I rarely ever drink liqueur or hard stuff. The problem is there is a lot of mis- information out there.
I google everything and do prior research before asking questions here.

The result of my search yesterday gave me an opposite view of what you just said. I can't find the exact article from yesterday but just pulled this up. I will listen to what you say and hold your opinion as fact and will NOT use the SLA 24V charger for lithium 18650 cells unless you tell me otherwise.

http://prntscr.com/jna9zc

There is the mis - information I was reading yesterday. Also I just remembered something from a few years back on this post. I think I tested the voltage when charging SLA with that 24V charger when you said I need a PROPER SLA charger. A three stage charger. If I remember coorectly the charging voltage on that SLA charger was very high. Around 29 volts I think. or was it the 36V - SLA charger was 39 volts ? I could try the multi- meter I guess.

The multi - meter obviously shows that it will overcharge the cells. 27.2V is still too high for Lion. 27.2 / 6 = 4.533 V.

Basically since I waited and asked you it makes me a very smart person , not a drunken idiot. It also makes you a genius as you were 100% correct and half or more than 1/2 like 90% of the people in these OTHER forums are complete imbeciles. :lol: I need to go get some coffee at Stewerts and an apple fritter. I got a discord meeting for my pirate game at 4 PM.

Thanks again DA.

LC out.



LC out.info.png
 

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The Google quotes were actually correct - for the chemistry they were speaking about.

24v lead acid chargers usually terminate at 28.8 or 29.6, depending on type.

8 Cell Lithium Iron Phosphate would give a terminating voltage of 3.7v per cell, or the ideal. a 28.8v charger would still charge to 3.6v, or about 95% full.

6 Cell Lithium Polymer would terminate at 4.8v per cell, or fireball. A 6 Cell LiPo battery is NOT the equivalent of a 24v lead acid battery. It would take a 7 cell battery to be 4.1v per cell, or 95% full.

In other words, the advice on the internet is not poor, you're just taking the advice for the wrong chemistry.
 
I am kind of lost. It is confusing. There are just too many battery types. What is really confusing is the LiLo button on the 6S LiPo charger. I remember about two years back using it to charge Lipo as I thought it would be safer. I thought it was for lithium ion which is what 18650 cells are right. however when I watch the you tube video 18650 cells are charged to 4.2V just like LiPo.

Also SLA batteries have a lot more power than LiPo or 18650 cells but they don't last long and are way too heavy. Basically the 18650 cells I ordered don't have much power at all. Any 6S LiPo pack I have ran defiantly out performs 18650 cells and SLA when fully charged is a little better than LiPo fully charged.

SLAs are higher voltage fully charged and LiPo higher voltage than 18650 cells even though they charge at the same voltage. The reason for 18650 cells is a better safety factor and they should last at least twice as long or double the charging cycles as LiPo and 10 times more cycles than SLA.

In about a month to 5 weeks I should have a second 24 cell - 6S - 18650 pack built and then in series it will be 12S. Until then I will pedal assist and deal with the pack I got for the Currie.

If I get the 1,800 watt brush-less motor and 72 volt 2,500 watt controller then I will build a third - 6S pack for the Haro V3.
18 * 4 = 72V. 18 * 3.7 = 66.6V. It should work for awhile but not sure about LVC.

The stock 48V brush-less controller which comes in the motor kit is 48V and 1,800 watts. I asked a few pages ago if it would be possible to squeeze 54 volts and 2,025 watts out of it. The 48V brush-less controller is about 1/2 price or $100 cheaper than the 72V brush-less controller.

There is no way I am NOT going to build a 40 mph e bike this summer so it would be useless to talk me out of it. I am going to look at BMSs and also 60V brush-less controllers. I would rather deal with a 60V than a 72V as the motor is rated at 48V and really do not want to blow it up. I just want to go 40 mph. thanks for posting.

LC out.

https://www.ebay.com/itm/60V-2000W-Electric-Bicycle-Brushless-Motor-Controller-For-E-bike-Scooter/391969202767?hash=item5b432f624f:g:NScAAOSw-uhaaT7o

OK. That is EXACTLY what I am looking for.

https://www.ebay.com/itm/5S-Lithium-Battery-18V-21V-15A-Protection-PCB-Board-Li-ion-BMS-Charger-Cell-Wire/302677252984?hash=item4678f85b78:g:bV0AAOSwTA1asPX1

I don't think I will find a 15S BMS and charger anywhere any time soon so will need to build three 5S packs. 25 cells per pack five rows of 5 in parallel series. 75 cells total. 3.7 * 15 = 55.5V. 4.15V * 15 = 62.25V. 1,800W / 48 = 37.5 * 60 = 2,250W = 40+ mph. :twisted:

Thanks for posting.

LC out.
 
A few factually wrong things there:

1. Lead Acid is 2.1v per cell nominal, compared to 2.4 (Lithium Titanate) 3.2 (Lithium Iron Phosphate), 3.6 (Lithium Nickel Manganese Cobalt) and 3.7 (Lithium Cobalt Oxide). There is no lithium chemistry that has a lower voltage than lead acid.

18650s can be any chemistry, but if it charges to 4.1, it's NMC, otherwise known as Li-Ion. If it charges to 4.2, it's Lithium Cobalt Oxide, otherwise known as LiCo or LiPo.

2. Lead Acid is about 180W/kg, where as Lithium is 240-350W/kg, depending on the chemistry above, so Lead does not have the power of Lithium - Unless you're comparing a car battery with a single 18650.

I believe a properly protected lithium titanate battery would be the best for your needs, in terms of short rides, but very high power. Over their life time, they would be cheaper than 18650 based LiCo, or Hobby LiPo, lasting 30+ years and 10k+ cycles, and not being so vulnerable to under/overcharge.

LTO.png

The real problem with these ones is that they need a spot welder to join. You can't solder to the tabs. Some people have modified them using a drill press to create screw tabs. I wouldn't risk it.

There are others that take screw terminals or solder, but they are more expensive, both absolutely, and on an $/Ah basis.
 
Here's one that's had screw terminals welded to the tabs that's not much more expensive:

https://www.aliexpress.com/item/5S-12V-3Ah-Lithium-Titanate-LTO-Pulse-400A-Discharge-Current-20000-Lifecycles-Car-Starter-Battery-Pack/32865928044.html?spm=2114.search0104.3.8.6d665d31k9TqME&ws_ab_test=searchweb0_0,searchweb201602_2_10152_10151_10065_10344_10130_10068_10547_10342_10343_10340_10548_10341_10696_10084_10083_10618_10307_10131_10132_10133_10059_308_100031_10103_10624_10623_10622_10621_10620,searchweb201603_19,ppcSwitch_5&algo_expid=225bde9e-2063-4a12-b98a-a19003461468-1&algo_pvid=225bde9e-2063-4a12-b98a-a19003461468&priceBeautifyAB=0
 
They look incredible. Each cell is 12 volts. and 3 AH ? let me look again.

Looks like I will need a lot of batteries to build a pack. My funds are very limited. I got a $311 electric bill which was supposed to be paid 4 days ago and I am almost completely broke.

I will research it but for now need another 24 cell - 6S pack with the same LG cells so I will have the 12S option and some power. The little purple 20" bike with the 1,000W - 48V Unite motor I had apart and repaired more than once I think it installed under the rear rack. It has a 48V Chinese controller. Also the 24" cargo bike with the 20" 800 watt hub motor on the rear and the Schwinn all will work with 12S LiPo.

thanks for posting.

LC out.
 
No, each cell is 2.4v. There are 5 cells per order = 12V battery.

If you want a 36v battery, you need 15 cells. 48v, 20 cells.

So each one is about four times the price of an 18650 of similar capacity, but will last 10x as long, and much harder to damage.

Trade off is that it is about twice the volume and weight of 18650s.
 
20 cells for 48V but only 3Ah ????

40 = 6 Ah

60 = 9 Ah

60 / 5 = 12 * $53:18 + shipping = approx. $650 for a 48V - 9Ah pack

Thanks but no thanks. I wish I had that kind of money but even if I did I would need a lifetime warranty for full replacement.

Even then How much would 60 of those things weigh. A lot more than four 10 Ah SLAs I would imagine. Unless there is something I missed.

https://spectrum.ieee.org/energywise/energy/renewables/does-new-glass-battery-accelerate-the-end-of-oil

Once these batteries become affordable they will be the battery of choice for everyone here on ES. However until then I will deal with 18650 cells. I also have the two 10.0 - 6S packs and the two 8.0 - 6S packs. Each with one bad cell.

I just am still a little scared of LiPo and really don't want to take them apart. However if I did manage to remove the bad cells I would end up with four 5S packs and could order 5S balance plugs for balance charging with either of my chargers. Thanks.


LC out.
 

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latecurtis said:
Thanks but no thanks. I wish I had that kind of money but even if I did I would need a lifetime warranty for full replacement.

Even then How much would 60 of those things weigh. A lot more than four 10 Ah SLAs I would imagine. Unless there is something I missed.

You are correct that there are trade offs, and I did not expect you to be able to afford them. They were brought up as an "indestructible" battery, since you seem to keep damaging yours, or at least getting less out of them than you would like.

You have missed two things - You can only safely use about 1/2 the capacity of an SLA unless you are satisfied with sub 100 cycles. Peukert's effect would also mean that you're not going to get anywhere near the 10Ah on the label.

The other thing you missed is less relevant. These babies could output in the multi-kilowatt range, and be charged back just as fast. Flooded lead acid would have a very high peak output, but SLAs usually are designed for things like UPSes and golf carts, and have lower discharge rates. Again, trying to push them hard will cause Peukert's effect.

All that aside, the 3Ah cells were never really meant to be put in parallel, they were designed to buffer energy at extreme levels. They can be charged faster than they can be discharged - and they can be discharged really, really fast. That 12V battery can put out 2.1kw. A 48v could put out 8.4kw. a 9ah version could do over 25kw. Even a flooded lead acid couldn't do that.

If you're looking at the 10ah range, it gets a bit harder, because the 10Ah batteries are still power dense, not energy dense, and so are still very expensive. When you get to the 20ish Ah range, that's when you start getting cost effective. I bought 60 of these. They are being held in customs:

My LTO.png

Using the same battery for you:

20 x $18 for a 48v battery = $360 + Shipping. I paid $8 per cell shipping to Aus. = $520.

48v x 28Ah = 1344wh. A well designed eBike can get you 20wh per mile, or roughly 67 miles.

It can put out 13kw without damage - That's easily enough to get you well over 60mph on a flat.

Using a 220v, 10A power point, you can charge it from flat in just over half an hour without damage. You could guerilla charge at shopping centres, reducing that electricity bill of yours.

With >25k cycles and 30 year life, excuse the morbidity, it's something you can leave in your will.

But... It's true what they say... The poor pay twice. Unfortunately, the likelihood is that you'll pay $50 here, $100 there for the next few years, getting batteries you're never quite happy with, and eventually spending more than doing it right the first time.

I'm not saying this to put you down. It's just a reality of life. :(
 
As the Hub Motor Turns and the LiPo Fire Burns. The East coast Death Bike. - 90 mph. :twisted:

Those numbers are impressive.

I would need close to $300 to get 60V and about $370 for 72V.

They would be great for the 1,800 watt 48V brushless motor and 2,500W variable controller.

Also If I came up with $700 or $1,100 someday would they work in parallel or not ? You said they wont work in parallel ?

I was thinking about the FX - 75-5 motor which is 45 kilowatts. I would need 120 volts I think to run that. Not sure but seems like the best choice in battery. About $550 for 10 = 120 volts and 10 more in parallel for 6 Ah is about $1,100. Will 6Ah work and will it at least get a death bike 1/4 mile at a race track ? Please let me know.

LC out.
 
They will work in parallel, they're simply not designed for it. You're just paying too much money. It's expensive to make a cell power dense.

If you were going to run 3 in parallel, you might as well go a larger cell that's energy dense instead. It will have a much lower C-rate (10C vs 175C), but 10C @ 20Ah, is still 200A. On a 48v bike, that's still 9.6kw.

3Ah would do you a quarter mile easy.
 
https://bmsbattery.com/ebike-battery/10-headway-38120s-10ah-10c-lifepo4-cylindrical-battery-cell-with-screw-headway-battery.html

20 of those in series would be 64 volts at 10 Ah. 64 * 100 amps = 6,400 watts. NOT good for the FX motor but perfect for the 1,800W brush-less motor.

1,800 / 48 = 37.5 * 64 = 2,400 watts empty.

37.5 * 74 = 2,775 watts full charge.

That is > 1/3 maximum discharge rate and < 1/2 maximum discharge rate. Also capacity is > 3 times the 3 Ah batteries.

The problem is lord knows what they want for shipping.

I will need help building the East coast Death bike. If I ever get a dirt bike frame and about $5000 to build it I could use some help if you ever get to the USA. Maybe for vacation or something. Are you still in Australia Sunder ? Did you say you was moving ? Let me know when you can. Thanks.

LC out.
 
Lord knows what they charge for shipping? Lord knows what you'd get, if you got anything at all.

I got burned by them bad. I got cells that died after just 3 months of light usage. One developed an internal short, and took out every other cell in the battery with it.

And when I ordered a 12S BMS, they sent a 16S by mistake, and told me I had to hack apart my battery to make it fit. I told them I wasn't hacking apart a $250 battery, voiding its warranty, because they sent me the wrong $40 BMS.

Paypal agreed and gave me the full money back, because they refused to.

If you want good quality cells, I've had two good interactions with OSN. They seem to get a good rap on here too.
 
Sounds good. I don't want to get robbed by e bay again.
The brown LG cells seem to have held up on the short test trip. that 750 watt 36V gear reduction motor however does not seem to have much power at all with 6S.

Tested the LG cells seem to be > 2 Ah so I would say close to 10 Ah. > 9 Ah and < 10 Ah down to around 3.2 or 3.3V per cell which is about as far as I want to run them.

The SONA batteries are two 20 packs at 2 Ah each cell. 2 Ah * 40 = 80 watt hours which gets me downtown and back but with a lot of pedal assist.

The LG cells will be 2 Ah * 48 -= 96 watt hours and should work with some pedal assist especially up hills. The Currie and the 20" purple bike is not as easy to pedal as the 700c hybrid. Especially the 20" bike.

Basically if I do not order 24 more of the LG batteries then the 24 cells I got now will only be good for 2 mile trips to Wall-Mart. The old LiPo packs will do that. Also I do not want to miss match cells. I need two 6S packs with the same cells all new.

I may build a third pack later on with the Westinghouse cells but will run it separate. Basically when making the 2 mile trip downtown to the beer store and my friends house it is either flat or down hill. A single 6S - 24 cell pack will do the trick.

The 1.6 mile trip back home from my friends house to my house is two small to moderate hills and also less pedal assist do to about 10 beers. Therefore it makes sense to run 12S ( the 48 LG cells ).

I will explore the better battery options you posted about when I build the 1,800 watt brush-less motor and 72V 2,500 watt controller for the Haro V3. Then I will need the better higher discharge hard to kill cells. Right now I just need decent cells for normal daily commute. Thanks again Sunder.

LC out.
 
latecurtis said:
The SONA batteries are two 20 packs at 2 Ah each cell. 2 Ah * 40 = 80 watt hours which gets me downtown and back but with a lot of pedal assist.

The formula for watt hours is Ah * nominal volts * number of cells.
So 2Ah * 3.7v * 40 cells = 296 watt hours. I would expect that should get you nearly 10 miles of travel if everything is working right, you are assisting a bit by pedaling, and you aren't going faster than 20 mph (25-30 watt hours per mile). But with only two packs, that may be stressing them pretty hard and you might not do quite that well. But you should be in the ballpark.

latecurtis said:
The LG cells will be 2 Ah * 48 -= 96 watt hours and should work with some pedal assist especially up hills. The Currie and the 20" purple bike is not as easy to pedal as the 700c hybrid. Especially the 20" bike.
I'll let you redo the math here.

latecurtis said:
I may build a third pack later on with the Westinghouse cells but will run it separate. Basically when making the 2 mile trip downtown to the beer store and my friends house it is either flat or down hill. A single 6S - 24 cell pack will do the trick.

The 1.6 mile trip back home from my friends house to my house is two small to moderate hills and also less pedal assist do to about 10 beers. Therefore it makes sense to run 12S ( the 48 LG cells ).

6s = 22.2 volts and 12s = 44.4 volts. Do you run 22.2 volts and 44.4 volts on the same system? Also, aren't these both odd voltages for most motors and controllers since most motors and controllers are either 24 volts, 36 volts, or 48 volts?

And finally, while it has been covered before, I'll say it again, it is generally better to run multiple packs in parallel (assuming they have the same voltage). Running a small single pack by itself will probably mean that pack will "wear out" faster.
 
6s = 22.2 volts and 12s = 44.4 volts. Do you run 22.2 volts and 44.4 volts on the same system? Also, aren't these both odd voltages for most motors and controllers since most motors and controllers are either 24 volts, 36 volts, or 48 volts?

I have three variable controllers with built in pot. for brush motors.

https://www.ebay.com/itm/PWM-DC-Motor-Speed-Controller-Adjustable-Variable-Switch-HHO-Driver-12V-24V-48V/111985975199?epid=568468581&hash=item1a12e25f9f:g:jsoAAOSwgY9XfcL5

Going downhill requires less power and can use 24 volts. return trip 48V.

Could you please tell me where to get the DC booster. I want to boost from 48 to 54 volts. I am ordering an 1,800 watt brush-less motor soon and want to go 40 mph. Please let me know. Thanks for posting.

Thanks for posting.

LC out.
 
latecurtis said:
Going downhill requires less power and can use 24 volts. return trip 48V.

Could you please tell me where to get the DC booster. I want to boost from 48 to 54 volts. I am ordering an 1,800 watt brush-less motor soon and want to go 40 mph. Please let me know. Thanks for posting.

Slight issue there. All motors have a no-load speed. The further you are from that no-load speed, the less efficient the motor is, the more heat it generates, the more likely you will burn it out. I almost feel like we've just gone back 200 pages to 2014, when you first burned out your motor.

Doubling the voltage *can* double the total power, but up a steep hill, is unlikely to. If you haven't had problems so far, I'd be getting off the bike at the top of the hill and putting my hand on the motor. If it's unpleasant to touch, stop doing it. If it's painful to touch, chances are, you're already prematurely aging the lamination on the windings, and you could find yourself with a burned motor before too long.

DC boosters greater than a few watts are pretty expensive, but you can get them on eBay by searching for dc boost converter. You're better off adding a few more cells to your pack than to try to get a booster. Not only is it cheaper, it's more efficient. Most boosters are ~90% efficient. The ones that claim any higher, are either outright lying, or doing a boost from say 48v, to 48.1v.
 
Doubling the voltage *can* double the total power, but up a steep hill, is unlikely to. If you haven't had problems so far, I'd be getting off the bike at the top of the hill and putting my hand on the motor. If it's unpleasant to touch, stop doing it. If it's painful to touch, chances are, you're already prematurely aging the lamination on the windings, and you could find yourself with a burned motor before too long.

Yes you That would be correct on the hill I burnt the original Currie motor out on or Crane st. hill from the bottom. I live on crane however never attempted it with an e bike.

The hills I am talking about are not nearly as steep or as long and the 1,000 watt 48V motor on the purple bike made it up the hills at 24V.
But Like I stated earlier 24V of LiPo or 36V SLA are much more powerful than 6S - 18650 pack. two in series for 12S will be much better on the little hills and won't burn out anything.

If I get a good deal on used 18650 cells I will attempt a 13S pack with a BMS from used laptop cells. two packs of 65 cells in parallel two BMSs sounds right. 13S Five strings of 13 cells all in parallel. It will work and on the cheap. Thanks guys and will post a video soon with the single 6S pack.

LC out.
 
latecurtis said:
Could you please tell me where to get the DC booster. I want to boost from 48 to 54 volts. I am ordering an 1,800 watt brush-less motor soon and want to go 40 mph. Please let me know. Thanks for posting.

Thanks for posting.

LC out.

You can do a search on Amazon or Ebay for the booster described in my signature. It is substantially cheaper on eBay, but you'll end up waiting much longer for delivery. But I wouldn't recommend it for increasing voltage from 48v to 54 volts. I'm using mine to move from 36 volts nominal to 54 - a much larger jump. I'm running mine really for three reasons:

1) I didn't want to rewire my 36 volt battery packs to be 48 volt packs and I didn't want to start swapping out controllers and such on my first build
2) I just enjoy trying things that are a bit unconventional.
3) I felt that it was worth it to get the extra speed and to not have my top speed constantly dropping as the battery voltage drops.

Based on what I've read of your posts, I think your money could be spent on other things to better effect - like more and better batteries.
 
Sunder said:
DC boosters greater than a few watts are pretty expensive, but you can get them on eBay by searching for dc boost converter. You're better off adding a few more cells to your pack than to try to get a booster. Not only is it cheaper, it's more efficient. Most boosters are ~90% efficient. The ones that claim any higher, are either outright lying, or doing a boost from say 48v, to 48.1v.

My experience with one boost converter is a little bit at odds with what you say.

Mine wasn't particularly expensive - less than $40 on Amazon and cheaper on ebay.

In my application it appears to be able to deliver a bit more than 1000 watts. That seems like a fairly substantial amount of wattage - enough to provide an illegal amount of power in California and soon in Arizona - though not as much as the batteries could deliver and my controller could consume if I changed its settings.


The booster claims an efficiency of 92-97% and I have every reason to believe that my use falls somewhere in the middle of that range. I'm boosting voltages ranging from 32v to 42v (36 volts nominal) up to 54 volts. That's not a huge jump, but it's well more than a mere fraction of a volt.

Monitoring wattage pulled before and after the converter while biking, I find about 5-6% more wattage consumed than delivered. The boost converter never gets warm. I think its cooling fan kicked on once, and that was for about five seconds. I barely had time to verify that the noise I heard was coming from the fan. Even in 90-100 degree weather, it seems no warmer than my bike frame. My LED headlight gets warmer than the boost converter. That the booster runs fairly cool suggests to me that it isn't using very much energy in the conversion. Also, my watt hours per mile power consumption is well within what is typically reported by others here who don't use a boost converter. In fact, it seems to be on the low side of typical.

For me, the negative of losing about 5-6% in efficiency has been well worth the handful of benefits it provides. But situations vary and its hardly something that most people should be putting on their bikes. I don't, for instance, think one would be particularly useful for LC.
 
wturber said:
My experience with one boost converter is a little bit at odds with what you say.

Mine wasn't particularly expensive - less than $40 on Amazon and cheaper on ebay.

That's fair enough, my view is more an opinion than hard fact. My needs were probably a bit higher than yours. I was converting 12v to 24v, at a fairly high load.

I've gone through three different models. First one current limited correctly, but was way too small. Never measured the efficiency on that.

Second set was rated at 10A for about $20USD each, but after 40 mins on 5A input, barely over 2A output, it melted. Literally, when I went to see why power had stopped, solder had melted and run off the fuse holder without the fuse tripping. Go figure?

Third one is a $80 40A rated one. It handles 30A input fine, only getting warm (I'd like to push it to 40A, but at this price, I'm wary of burning it out and can live with 30A), but I measured the output, which if it was anywhere near the 92% efficiency claimed, should have been around 14A, but it was closer to 11.

I have read other people say before that the "maximum efficiency" claimed on most of these cheap parts are "perfect condition" efficiencies. While good ones have an efficiency curve pretty close to the maximum efficiency point, cheaper ones fall off from the curve pretty fast.

Could be you just got a good one cheap.
 
For me, the negative of losing about 5-6% in efficiency has been well worth the handful of benefits it provides. But situations vary and its hardly something that most people should be putting on their bikes. I don't, for instance, think one would be particularly useful for LC.

Well That depends whether I want to go 36 or 37 mph or > 40 mph. The 1,800 watt brush-less motor if still available have different options. The last I checked there was a 4,500 rpm model and a 3,300 rpm model. Also these motors can be sold separate or with the controller and throttle in a kit.

Obviously in the kit there is a discount but the controller is rated at 1,800 watts. I would require a 60 volt pack for 2,000 watts and a 72 volt pack for 2,500 watts and in either case a more expensive controller however do not want to destroy the motor so am looking at two options without the booster.

1, 60 volts for > 2,250 watts. - 60V 18650 pack. moderate risk for motor failure >40 mph capable.

2. 72 volts for > 2,500 watts - 72V 18650 pack. great risk for motor failure 42 - 44 mph capable.

3. 54 volts with boost for 2,025 watts - 48V - 12S lithium pack. minimum risk for motor failure. 40 mph capable.


Obviously option 3 is cheaper as a 12S pack will do the trick and safer for the motor. It is a no brainier if the booster is around $40. It would cost more to build a larger pack. Please note I do not plan on going much over 30 mph for any extended period of time. It is a lot like driving a new car.

Most people do not drive more than 5 or 10 mph over the speed limit on a daily basis but those same people will try it out on the expressway when there is not a lot of traffic to see what it is capable of. Maximum speed maintained for a short period of time.

My question is does the controller hook up to the booster then to the motor ? That would seem logical. Also is there an off or on switch ?
It probably would not need one as 48 to 54 volts is really not a huge jump in voltage. I will research these boosters now. Thanks very much for the information and looking forwards to further posts regarding this subject. Thanks.

LC out.
 
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