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I am planning on building several 12V starter battery packs for the all the junk vehicles I have sitting around. Tried a 4s4p pack and it works dandy.
After reading a bit more on how to promote longevity on the Lifepo batteries I am thinking of building 7s5p packs to have a little more cranking amps and also to promote longevity.
Battery cells: A123 -ANR26650M1A --> nominal voltage 3.3V / 2.3ah ( 10 sec. discharge rate up to 120C)
On a 4s4p configuration these would sit fully charged at 13.3V and have a 9.2 Ah capacity
On a 7s5p configuration it would be 16.6V and 16.1 Ah.
The alternators of most of the cars output is 14.4V which on the 4p pack means they could be overcharged and on the 5p configuration would mean the cells would be charged to 86% max - I think.
Am I looking at everything correctly? Any different configuration or improvements I could make? How about running these packs without BMS?
After reading a bit more on how to promote longevity on the Lifepo batteries I am thinking of building 7s5p packs to have a little more cranking amps and also to promote longevity.
Battery cells: A123 -ANR26650M1A --> nominal voltage 3.3V / 2.3ah ( 10 sec. discharge rate up to 120C)
On a 4s4p configuration these would sit fully charged at 13.3V and have a 9.2 Ah capacity
On a 7s5p configuration it would be 16.6V and 16.1 Ah.
The alternators of most of the cars output is 14.4V which on the 4p pack means they could be overcharged and on the 5p configuration would mean the cells would be charged to 86% max - I think.
Am I looking at everything correctly? Any different configuration or improvements I could make? How about running these packs without BMS?