Quote:
Originally Posted by mechman600
a lithium pack will normally stay balanced on its own for quite a while. But it will need a re-balance one in a while, which is time consuming. I think an EV should take care of itself with no tinkering required.
Also, why spend $10K on a battery pack and not $800-1000 on a BMS system? It seems like an insignificant amount for some insurance.
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That is the argument from the battery management camp and was my thought too until I started reading the rebuttal from those who are proponents of bottom balancing and battery monitoring. The thing is, I'm not convinced any more that it is insurance as much as adding a risky failure point for the sake of convenience. If the BMS board (probably made in China) fails, it can kill cells. It requires the cells to all be slightly overcharged every cycle in order to balance them which is hard on the cells. It does provide a high and low voltage cut off, but you can do that with a cheap monitoring system.
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Almost all my driving is done 1-5 miles at a time.
Best short trip: 2.4 l/100 km, 3.9 km