90V high amp battery needed

Batteries, Chargers, and Battery Management Systems.
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Valheria   1 mW

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90V high amp battery needed

Post by Valheria » Oct 04 2014 6:04am

Hey guys

I am getting a Qulbix raptor frame E bike built for me soon with a cromotor.

Assuming it is 6kw i want to do 90v at 66 amps or so continuously. does anyone know where i could get that kind of battery without using LIPO due to short life and fire hazard? I would prefer lifepo4 in pouch form as it needs to fit in a small space

here is the frame details http://www.qulbix.com/index.php?option= ... C_UFvldVs4

I found a good 90v hpc battery that can do 100amp discharges on 13ah but is that any good or a big rip off? because im new to this kind of stuff hence why im getting i know to build it for me as it has did converted my 1000w E bike for me

Any help/tips would be greatly appreciated guys on

dnmun   100 GW

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Re: 90V high amp battery needed

Post by dnmun » Oct 04 2014 9:19am

90V DC is close to the fully charged voltage of a 24S lifepo4 pack. a 24S lifepo4 pack is known as a 72V battery and charges to about 87V. if you need 45A peak current then you should use at least 15Ah wide but 20Ah wide would be better.

the lipo fire hazard is always overstated here and there has not been a fire caused by overcharging lipo reported here.

if you use a BMS or balancing charger it should never be an issue.

the risk of fire is from shorts in the wiring. one of the balancing chargers, the BC168 has caused fires by melting the sense wire insulation off at the high currents it delivers and that has caused at least one known fire, because of shorts in the sense wire plug/cable but not from overcharging. so if you can avoid using that charger then you should not have any more risk in using lipo.

the short life cycle of lipo can be mitigated by not charging the cells to full voltage and leaving them fully charged. if you leave them only partially charged until you need them and then charge them immediately before use the cycle life is maximized. do not charge in cold temps or hot hot temps either.

kriskros   10 kW

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Re: 90V high amp battery needed

Post by kriskros » Oct 04 2014 5:52pm

multistar lipo from honk kong hobby could be a possible... each pack is 22 1/2v,16ampd..wt 4lbs..cost $123.oo us from the US warehouse.. put some of those together and you can make whatever you need :mrgreen:

ARod1993   100 W

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Re: 90V high amp battery needed

Post by ARod1993 » Oct 04 2014 9:24pm

Doing that kind of power without resorting to LiPo is going to be hard to do cheaply. If you want to do LiFePO4 pouch cells, then the highest-quality (but most expensive) solution I know of would be to get two cartons of the A123 prismatic cells, use 24-28 of them, and find buyers for the remaining 10-15 cells to offset the extra cost. The other way to do high powered LiFePO4 would be to buy 150-200 of the A123 26650 cells, available here, and put together 15-20Ah of those at 24-28s; that obviates the risk of buying $2600 of batteries and promptly trying to resell a third of them, but the costs of that route would be around $1700 or so up front, maybe a bit more. On the flip side, those things are tanks; you can get 120A pulse, 70A continuous out of an A123 26650 (and apparently something like 700A out of the prismatic cell) for well over a thousand cycles before they start to lose capacity, and the 26650s can take a great deal of abuse without venting or being ruined by the experience. Other options include building a 24s Li-ion pack out of the nice Samsung 25R cells, if you can find a bulk source for them. Apparently there's a hobby community oriented around running really low-resistance heating coils inside e-cigs and vapes, so there are a number of places online that will sell you 25Rs at $8 apiece. If you can find a way to get them in bulk for $5-$6 then you can build up an 88.8V nominal 20Ah pack for around $1000-1200 in batteries, which isn't too terrible as far as costs are concerned. You could probably do a 100A pack for decidedly less money with hobby LiPo, but the above options will work if you'd rather not go that route.

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Schlafmutze   10 W

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Re: 90V high amp battery needed

Post by Schlafmutze » Oct 05 2014 7:47am

24 cell of a123 20ahs don't fit in the raptor, either of them.

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Valheria   1 mW

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Re: 90V high amp battery needed

Post by Valheria » Oct 06 2014 11:30am

ARod1993 wrote:Doing that kind of power without resorting to LiPo is going to be hard to do cheaply. If you want to do LiFePO4 pouch cells, then the highest-quality (but most expensive) solution I know of would be to get two cartons of the A123 prismatic cells, use 24-28 of them, and find buyers for the remaining 10-15 cells to offset the extra cost. The other way to do high powered LiFePO4 would be to buy 150-200 of the A123 26650 cells, available here, and put together 15-20Ah of those at 24-28s; that obviates the risk of buying $2600 of batteries and promptly trying to resell a third of them, but the costs of that route would be around $1700 or so up front, maybe a bit more. On the flip side, those things are tanks; you can get 120A pulse, 70A continuous out of an A123 26650 (and apparently something like 700A out of the prismatic cell) for well over a thousand cycles before they start to lose capacity, and the 26650s can take a great deal of abuse without venting or being ruined by the experience. Other options include building a 24s Li-ion pack out of the nice Samsung 25R cells, if you can find a bulk source for them. Apparently there's a hobby community oriented around running really low-resistance heating coils inside e-cigs and vapes, so there are a number of places online that will sell you 25Rs at $8 apiece. If you can find a way to get them in bulk for $5-$6 then you can build up an 88.8V nominal 20Ah pack for around $1000-1200 in batteries, which isn't too terrible as far as costs are concerned. You could probably do a 100A pack for decidedly less money with hobby LiPo, but the above options will work if you'd rather not go that route.
Yeah the pouch cells was my first idea but i lack the expertise to put something like that together safely in the first place so i always knew i need a company or individual to build a pack for me.. But them pouch cells are too big to fit in the quantities needed which is a bummer. the last idea you mentioned sounds okay . can you send me a link for one of them cells because the ones i found are 2500mah each.. so i would assume i would need ALOT to get 20ah? But i would need many bms's though if i used 100's of cells right?

dnmun   100 GW

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Re: 90V high amp battery needed

Post by dnmun » Oct 06 2014 11:39am

no, you only need one BMS for the entire battery. if you cannot solder the aluminum positive tab of the A123 pouches then it will be useless to consider using them in a pack. or you have to use one of the clamping methods in the A123 pack thread.

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Valheria   1 mW

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Re: 90V high amp battery needed

Post by Valheria » Oct 06 2014 11:56am

dnmun wrote:no, you only need one BMS for the entire battery. if you cannot solder the aluminum positive tab of the A123 pouches then it will be useless to consider using them in a pack. or you have to use one of the clamping methods in the A123 pack thread.
I found these battery packs
http://em3ev.com/store/index.php?route= ... uct_id=134

The 22ah version can do 40amps at 50volts etc

if i got two of those to fit in the compartment which i can it seems and had them wired in series. Would that give me 100v with 80 amps? but ideally i want to use 90v 66amps. Is it possible to to ignore the extra voltage or would i have to run it at 100v? i don't know much about this stuff so forgive me to saying some crazy silly things in these posts hah But i want to say that this going to be used with a kelly controller powering a cromotor at 6kw would there be any issues i need to be aware of?

Also does anyone know what the cromotor can take (max amps etc etc ) and the lowest amount of power it would accept as i want to be able to make it road legal at 250w for my local commute of 1.2 miles : ) ..i am lazy heh

dnmun   100 GW

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Re: 90V high amp battery needed

Post by dnmun » Oct 06 2014 12:05pm

you can look at tommyL's thread on the EM3EV pack he got. there was another thread where people reported problems with the BMS but they were so lame they would not test the BMS to see what was wrong with it. just more lazy ass tourists here playing the 'i am rich so i don't fix or analyze stuff' game.

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wesnewell   100 GW

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Re: 90V high amp battery needed

Post by wesnewell » Oct 06 2014 12:50pm

If you put 2 40A 50V battery packs in series, you get 1 40A 100V battery pack. if you put 2 40A 50V packs in parallel, you get 1 80A 50V pack. The cromotor doesn't draw any amps from the battery pack. It gets its power from the controller, which takes the power from the battery pack. You match the battery pack to the controller, not the motor. The motor size is irrelevant.
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