BMS necessary??

[Serch]

Hi.

I want to replace my lead battery in the car of a pack 4s1p (20Ah) LiFePO4 and I do not know if I need a BMS ... I need ?? How many amps ??

Thx, Sergio

 

[mlt34]

I think you'll want to do some more research. Car batteries are designed to put out serious amounts of current, 500A or more. LiFePO4, even the best A123s at 20AH, isn't going to be able to put out that much current. Lipo could put that current out, but you'd have a bunch of safety concerns to deal with in terms of safely charging that stuff off your alternator.

 

[Serch]

Ops...

I have a friend that in your car have a 4s2p of 2500mAh and can tell you that the car runs perfectly.

The A123 batteries, i.e. 20AH, can put out 30C, 20*30=600A (peak)

I think that we can put them in the cars... but, I don't know, if we will need a bms...

 

[dnmun]

sure you need a BMS. you need to adjust the voltage output of the alternator also so the cells do not overcharge. or if it is just for a short period of time such as in a race car, you can skip using a BMS or adjusting the alternator voltage and just get new cells to replace them for the next race.

 

[mark5]

Lithium Batteries - Not Just for Hybrids
These batteries have advantages, but they're certainly not everyone's prime-time choice.
http://www.roadandtrack.com/lithium-batteries---not-just-for-hybrids

Porsche's New $1700 Car Battery: What You Get
http://jalopnik.com/5527441/porsches-new-1700-car-battery-what-you-get

 

[wesnewell]

Check the output voltage of your regulator. As long as it's 14.5V or lower, and it should be, I wouldn't use a bms. Besides, you'll be hard pressed to find a 4s bms capable of 600A output. And if you do, it will be expensive. Although I don't think you will need more than 100A. Check the starter specs for max draw.

 

[999zip999]

Yes a bms is needed for a lifepo4 car battery. Don't waste your money just buy a lead and it will last 4-6 yrs. It's it. Lead is perfect for a car. lifepo4, lipo ect is not the right match. Maybe in 3-5 yrs. Don't over think it. The altenetor charges to high for a lifepo4 battery. Call AAA and they come to you 2 yr warranty replacement non pro rated cheaper than Orielly's and if in trouble on the road they bring a new battery to you a no brainer. Remember you didn't fill in where you live an important part of helping you.
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