24v 20AH LiPo or LiFePO4?

[wildnrg]

I've current got a 24V 10AH LiFePO4 battery pack, I'm looking at going for a 20AH battery pack.

I've been look at some LiPO 40A discharge packs and LiFePO4 100A discharge packs.

My 500w motor shouldn't draw more than 40A, and the LiPo pack is listed at 3748grams versus about 8000grams for LiFePO4

Price wise they are around the same price.

Which one do you think I should get and why?

 

[lesspedal]

I've been considering lifepo4 20 ah from ping.
From what i have read on here, lipo can burn your house down, unless you know what yur doing.
Trev.

 

[wildnrg]

LoL then I hope my phone batt doesn't burn a hole in my pants.

 

[lesspedal]

Your phone will be li ion not lipo.

 

[AussieJester]

LiFePO4 100A <--got link please?

Cheers

 

[liveforphysics]

Your phone will be li ion not lipo.

Wrong.

Also, a ping battery is LiPo. The chemistry determines if a battery is a volatile chemistry, not the choice in polymer or liquid for electrolyte.

A LiMnCo LiPo pack, like 6s 5Ah RC packs run 4P to give 20Ah would be a battery able to dump 400amps easily. It would handle whatever small amp load you are planning to draw from it with just a small fraction of a volt of voltage drop. It could be charged in 20-30mins if you have a strong enough charger. If you don't follow the rules of LiPo, it can burst into flames. If you do follow the rules of LiPo, it's fine. You will require having an RC charger.

The Ping pack would be about twice the size and weight, cost more, have lots of voltage drop and require slow charging. Very weak batteries. However, on paper it's going to get more cycles, and shouldn't burn your house down unless you really work at it.

Don't consider LiMnCo LiPo until you've read through the stickied thread in the battery section covering how to safely work with LiMnCo LiPo.

-Luke

 

[lesspedal]

well there you go wildnrg.
Thanks luke.

 

[wildnrg]

LiFePO4 100A <--got link please?

Cheers

www.cyclone-tw.com

They see 100A packs using 10C cells.

 

[wildnrg]

Can anyone see any problems with me just buying a second 24V 10AH LiFePO4 battery, making a Y cable and linking the battery packs up in parallel to give my 24V 20AH?

Obviously I'd have to charge them separately, but I see the advantage of 2 x 10AH is that can you one for short trips and save 3kg, or two for longer trip.

Plus it'd save me $300USD on getting a 20AH

 

[Drunkskunk]

Can anyone see any problems with me just buying a second 24V 10AH LiFePO4 battery, making a Y cable and linking the battery packs up in parallel to give my 24V 20AH?

Obviously I'd have to charge them separately, but I see the advantage of 2 x 10AH is that can you one for short trips and save 3kg, or two for longer trip.

Plus it'd save me $300USD on getting a 20AH

Best way to do it, in my oppinion. Its best if the batteries are of the same brand, capacity, and approximate age. But it will be fine if they aren't

 

[wildnrg]

Can anyone see any problems with me just buying a second 24V 10AH LiFePO4 battery, making a Y cable and linking the battery packs up in parallel to give my 24V 20AH?

Obviously I'd have to charge them separately, but I see the advantage of 2 x 10AH is that can you one for short trips and save 3kg, or two for longer trip.

Plus it'd save me $300USD on getting a 20AH

Best way to do it, in my oppinion. Its best if the batteries are of the same brand, capacity, and approximate age. But it will be fine if they aren't

Yes if I got for a second 10AH instead of a 20AH, it will be the exact same brand, my current 10AH pack is only 1 day old. I use don't have much experience with LiFePO4 packs, I know that with NIMH if I want more capacity I just wire the same V and AH packs in parallel and magic I double the capacity, wasn't sure if it would be the same for LiFePO4 packs.

 

[lesspedal]

Can anyone see any problems with me just buying a second 24V 10AH LiFePO4 battery, making a Y cable and linking the battery packs up in parallel to give my 24V 20AH?

Obviously I'd have to charge them separately, but I see the advantage of 2 x 10AH is that can you one for short trips and save 3kg, or two for longer trip.

Plus it'd save me $300USD on getting a 20AH

I'm not electronic expert but i remember seeing on here, if you parallel two lifepo4 packs you need diodes on positive leads to protect bms.

 

[monster]

you don't need diodes. i have paralleled 12Ah ping packs and this works just fine. i've had BMS cut outs for random sht and it don't hert the other packs bms. series is the one where you need diodes for ping batteries anyway.

 

[Drunkskunk]

I'm not electronic expert but i remember seeing on here, if you parallel two lifepo4 packs you need diodes on positive leads to protect bms.

Series needs the diods. Parrallel doesn't.

Since they will be so close in age, and the same type, It might even be possable to charge them together, depending on the way the charger hooks up.
If you charge through the main power wire, then you can. if you charge from a seperate charge port on the BMS, you need to unhook them first.