Brian wrote:
James Sweet wrote:


They can hold up to a tremendous amount of abuse, but deep discharging
will kill them just about every time.

And the result is ...

They wouldn't even start to take a charge. My trickle charge reported
both were fully charged, even though they were totally dead. Even a
couple of hours on each wouldn't make them budge.

So, time for some new batteries. The originals were made in China. Will
hopefully remember to post whether the new batteries fixed the unit.

-Brian

P.S. There are four small-matchbox size black boxes on the unit's PCB.
I think they are relays. My guess would be that the batteries must
have some juice to keep one of these relays closed -- and that relay
admits line voltage to the entire device. Would explain the total
non-response from the UPS when plugged in with dead batteries.


You can hook up just about any lead-acid battery of the correct voltage
for testing, should be fine to jumper it to your car battery to see if
it powers up, mind the polarity though.