On Wed, 4 Jun 2014, Paul Thornton wrote:
> A UPS that drops the load as soon as the mains power fails
Have you load-tested the batteries? If not, get a drop-tester or
other large dump load, and see what happens to the voltage when you
try to pull **40kW** off the batteries.
It sounds like the UPS isn't useful at the moment anyway; so secondly
unplug the battery banks and allow them to settle for a day, meter and
write-down the unloaded voltage across each cell, and if they are wet
cells, check the specific gravity. See how much variation there is
from the specified SG for that cell type, and more importantly, from
each other. Most likely 10%-20% of the cells will be duds.
I suspect it's likely that the inverter/UPS itself is fine, the caps
in inverter are going to be huge, so check for signs of black
smoke/popped capacitors/blown power transistors.
-Paul
