Quote:
Originally Posted by kennybobby
If you check the DIY electric car site there is a thread (search Elithion's posts) with a count of the number of cars that burned up--the largest number were top-balancers using a BMS. If you want a sure fire way to burn your garage down then just put your trust in a BMS and let it control your charging.
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There is a difference between balance boards and battery management systems that top balance, because I have seen a handful of balance boards that just "prevent" each cell from going over the set voltage and bleed the extra energy off as heat and that is where fires can start!
If you are dumping in 10a or 15a or even more amps in to a battery pack and you have a 1/2amp resister that bleeds off power when the battery is up to voltage then something is going to go wrong and at some point you are going to have a battery swell or start on fire!
A battery management system needs to be able to manage the pack, it needs to be able to talk to the charger and throttle back the charger if ANYTHING is going wrong, it also needs to be able to cut power to the controller if anything is going wrong and it needs to have thermo sensors on each battery to shut stuff down if it's getting hot.
We have a bunch of members in our electric car club with lithium batteries and a few of them have destroyed batteries by trying to watch a battery as it charged to make sure it didn't over charge, doing that is like trying to catch your toast out of the toaster as it pops up, only your toaster is taking many hours to toast, you turn around and your battery is over charged and destroyed!
But most of the batteries have been destroyed by bottom balancing.