So, I finally finished rebuilding the rear battery box in my Electric F-250.
(replaced some damaged Leaf modules, and changed the module mounting to
electrically isolate it from the battery box.)
I've also updated my BMS design to be easier to work with, and more compact.
Re-installed the battery box, and started charging. One of the BMS units lit
up after only about 10 minutes. Since these are completely new, and had just
been setup, I was hoping that the unit was bad. Swapped it for another - and
the same module lit up again.
Did some testing with a multimeter, and found that 1/2 of a Leaf module is bad.
While charging, the voltage on that half is NOT increasing, unlike every other
module in the pack.
So, since I have module sets of 3 in parallel, the voltage on that module is
being forced to be the same as the other 2 good modules.
This means that the "good" 1/2 module is seeing a voltage much higher than the
bad 1/2. As things charge, it quickly reaches the "full" voltage, and triggers
AARRGGHH. If it was a bad BMS unit, I could quickly swap in a new one.
Since it's a bad module, I have to pull the battery box out of the truck again!
This is a several hour job for 2 people.
Seems that this one module must have been slightly damaged in the "event" I had
that visibly damaged several others.
Note: Yes, I had checked the voltages on the modules in the pack, and they were
all consistent. Apparently this one has some damage that doesn't let it charge
Tigers prowl and Dragons soar in my dreams...
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