These use 24Vdc battery configurations.

4 12V batteries.

Not in series....
Not in parallel...

They're in series/parallel!

Two batteries are wired in series then joined, in parallel with the
other two (also wired in series) to present a 24Volt battery pack to the
inverter/charger.

These are indeed smart units, with a microprocessor onboard, etc.

What I think has happened is that the batteries needed to be replaced,
as the originals failed. Done.

The problem is the smart charger doesn't "know" it has new, improved
batteries.

Last time it was pushing harder than ever to try to force a charge into
the years old batteries.

Now it has new, fresh, tender lead plates to play with but doesn't know
it. It still "thinks" old stale bad batteries.

The solution?

Not sure, and I too have had to extract my new now-bloated batteries
from my similar units...

Reading other's posts I saw recently what I think may just be the
solution. They were speaking of a SU600.

The solution is to use their software, and connect the SmartUPS to your
PC's serial port to do so... As it really oughta be already...

Then preform a "Runtime re-calibration"... The exact term escapes me for
the moment... I think thats it.

Doing so causes it to switch to inverter and then time the depletion of
the batteries. Then when it recharges them it may learn their capacity, etc.

I hope this'll get it done and before I go spend another $100 on new
cells for either of mine (again) I hope to hear back from someone about
this.

My expectation is that the charger won't try as hard once it learns it
doesn't have to. Is this proper thinking?

I do know this: APC's out of warranty partners CBMI are good folks. And
for something like $50 they'll re-cal your unit.

The bad news is the expense of shipping these all over the US. They have
2 service centers now, one in NJ and one in Las Vegas... I think.

Hope this helps.

Jack


P.S.

The re-cal is done via the serial port. They connect and send it new
parameters. The protocol is proprietary and will likely never be known
on the street. Non-disclosure agreements with APC prevent it, etc.

And nobody's hacked it.


WEBPA wrote:

The charger is most likely set higher than it ought to be. 13.5 vdc is
correct, IIRC.

But you may have a MUCH bigger problem. You stated that your out-board
batteries were "...connected in series." A series connection of 4 twelve volt
batteries makes a 48 volt battery. Your charger cannot charge this, and your
inverter will be destroyed if it ever tries to assume a load. Or...you mean
the 4 twelve volt batteries are connected in parallel. Much different.
webpa