The batteries (8 total) were originally set up to charge/discharge all
batteries from both inverters. This is a parallel circuit arrangement. The
batteries were in parallel with the inverters. This allowed all of the back
up circuits (6 total circuits) to have available all of the battery power
and keep the back-up load balanced. It was considered a feature and one of
the reasons I bought the system.
But this was also the means to have the current back feed through the
battery charging circuitry. After our first inverter fire, while the
factory representative was out at our house my wife noticed that there was
back feed this way. The batteries were "charging" with a negative current!
The company immediately issued an edict stating that the in-parallel
circuitry be discontinued to ALL their inverters with battery backup and
corrected in those where it was installed that way. Now they are in series
off of each inverter (4 batteries per inverter) and the two battery banks
are NOT connected. (I don't like this setup because I have 1/2 the power
available to my circuits and I now have to calculate my load on the
batteries and balance the circuits accordingly - meaning move circuits from
one battery bank to another to balance the load when running on batteries).
I get the feeling they didn't test this scenario very well - two inverters
powering 1 battery bank.
The components just were not capable of handling the current that was
passing through them. We have pictures of the charred circuitry and melted
components that we took before the units were removed. On partly cloudy
(more reflective sun light), cool days (low 70's around here) the PV panels
and inverters are capable of higher output. That may have been a
contributing factor because the components were highly stressed over time
and it was not a hot day on which they failed either time.
Beacon's website states explicitly that they do not support the Advanced
Energy products because they had design problems which have now been
corrected with Beacon's M5 product. The MM3000 was listed in that context.
I have no schematics or software for it either.
http://www.beaconpower.com/support/AdvancedEnergyProducts.htm
My opinion: I would not buy any Advanced Energy Inverter product, myself. A
potential fire is not worth any "deal" on the product. But your experience
may vary from mine, just keep a fire extinguisher handy