TechWriter wrote:
I didn’t catch how many BMS systems the Solar City guy tested, but I’ll take a SWAG and say 1. But let’s say 5 for argument’s sake.
So given his statistical sample size (n=5), I think it’s a stretch for him to condemn 99% of all BMS systems.
But, hey, it’s the Internet where personal experience (n=1) trumps all.
However, it brings up the fact that BMS DOES add an additional "layer" to your system which can, does and will break before the batteries really wear out.
I can speak from my own experiences with a device that my one employer sold that the Lithium battery BMS sometimes failed, rendering the battery dead with zero hope of revival for said battery.
Failing on the dead side is a good thing, much better to be safe than have it fail allowing over charging and over discharging to happen without the safe guard of BMS..
My own experience was with "more than one" Lithium battery, at the peak of that device we easily had around 25K-30K of the devices deployed and in active use at the same time. My group serviced those devices in house. When they broke the customer would send it to us, we would then troubleshoot and repair and return to the customer..
Was not unusual to have to work on 400-500 per week average.. Of those nearly half had dead batteries which would not power up the device nor charge when placed in our external charger..
Cracked open the sealed battery case on a few and discovered the battery had a charge (had voltage and you could power a load when you bypassed the BMS connection). Basically pointing to the BMS chip failure..
I would not recommend bypassing the BMS, it is there to reduce the chances of a catastrophic event..
When playing with any rechargeable Lithium battery, you should have a lot of respect for the energy they can store..
