Starting Battery - HEADWAY 38120 HP LIFEPO4 LITHIUM BATTERIES

[chickon1]

Finally installed this build today. I have been researching for a while weather or not to use a BMS or not. Trying to find something at a decent price and not at POS is a bit challenging that will hold the kind of amps I'm looking for (200). I bought these used off of ebay for $40 for 4 of them. They all checked out with good voltages.

I said 13.8 amps, meant volts. Each battery is 8 ah, 3.2v. They also make a 10ah that would be great for a second battery build. I'm getting 16 ah out of these, but I can charge and discharge them like 10k times and still have 75% capacity vs. Lead.. you get maybe 500 cycles @ 50%.. not bad for around $100 bucks. I could easily fit probably 3 more 12v packs just were the starter battery goes. I don't run a lot of accessories off the battery so no need to build a crazy second battery, but I bet I could get up around 100ah on the second tray easy.


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[Mike6158]

You need a BMS to keep the cells balanced and charge controller to prevent over charging (and the battery failure that could go along with that). Genasun makes a good charge controller (probably not good for underhood use though).

I built a 30Ah, 15Ah, and 10Ah pack (18650's). I use them to power Ham radios. I also have an A123 pack that puts up some very dangerous dead short current in spite of their small size. The instantaneous current capability of those things is unreal.

I don't think I would put them under the hood but they are a much safer battery than Lithium Ion batteries

 

[chickon1]

You need a BMS to keep the cells balanced and charge controller to prevent over charging (and the battery failure that could go along with that). Genasun makes a good charge controller (probably not good for underhood use though).

I built a 30Ah, 15Ah, and 10Ah pack (18650's). I use them to power Ham radios. I also have an A123 pack that puts up some very dangerous dead short current in spite of their small size. The instantaneous current capability of those things is unreal.

I don't think I would put them under the hood but they are a much safer battery than Lithium Ion batteries

I would definitely agree that heat and overcharge/undercharge and floating are the biggest issues. I need a BMS that can handle at least 150 amps of draw and that's not including the starting amps (which I need to measure), which is hard to find reasonably priced.

I took a temp reading with them under the hood and they are @ 125 degs F..that's after driving about 30 miles and letting it sit for 10 mins with the A/C on.. It around 85 degs outside. It's weird that they are the coolest thing in the engine compartment. Everything else is around 135.


Operating range peaks at 150 def F. So I think I will move them to the back here in the near future.