Jim Wilkins <murat...@gmail.com
> The only gadget like that I have is the APC1400 UPS. It charges the
> batteries to the programmed float voltage at up to 6A whenever plugged in,
> whether On or Off. You won't know what yours is doing unless you measure the
Mostly I was just curious how battery charging is done on gadgets like this.
It's a commodity product apparently, with lots of vendors selling very similar
devices differing only in power ratings and packaging. Many seem to use the
same display and keypad.
For now I've accepted the charging performance as "good enough". I don't
like the standby draw (11-12 W) but can live with it.
> You could parallel an external charger and perhaps have more choice of
> charging rate, float voltage and battery type. As long as it doesn't have a
> higher voltage desulfating mode it shouldn't hurt the ampinvt, it's just
> keeping a battery within its normal voltage range. If you don't trust your
> wiring skills the battery leads on NOCO ($$) chargers end in ring terminals
> that can be unbolted from the alligator clips and attached to the battery.
It appears that turning off the charger function (setting it to 0%) can
have some unexpected consequences. I tried it, then set the inverter to
"off", meaning no inverter output, no AC line passthrough via the
transfer switch. The input current started to periodically rise to
high (~200W) power, the alarms beeped briefly and then things went back
to normal. Clearly, 0% didn't mean off unconditionally.
The cycle repeated at intervals of a few minutes. The first time this
happened I heard crackling noises, seemingly inside the inverter, which
is what provoked my opening it up to look inside. Subsequents tests were
without any rice crispies sounds, even during power excursions
There was nothing visibly wrong and on reassembly the inverter worked
normally. There are no manual controls at all, but I do see a 4 pin header
marked 5V TX RX G so there seems to be a serial interface. Since everything
is done in software, anything is possible 8-)
Thanks for writing!