Re: Disconnecting charge controller after bulk phase?
Please do not take offense, but this set-up doesn't make sense.
First of all, the output from an FM80 is up to 80 Amps at any system Voltage. Four of them could push out 320 Amps in parallel, if you have enough panel to drive them all. For any size system, this would be in the realm of a megabank of battery. Otherwise you're pushing the charge too fast.
Secondly, once Absorb Voltage is reached it stays there; current is reduced so that the Voltage level is maintained. It wouldn't matter how many FM80's were attached: if they're all programmed alike, they'll all respond alike.
Thirdly, if you've got four you either have to have four RTS units or else (and this is a really good idea with this many units) have all the charge controllers communicate through an Outback Hub and controlled by a MATE.
May I ask just what sort of system you've got in terms of battery capacity, array size, system Voltage, and inverter? I've never encountered anyone needing 320 Amps of charge current before. I'd suspect you have a massively over-sized bank on a 12V system when you should be going up in Voltage to supply the power requirements.
I don't mean to be mean, but the idea of having four FM80's just floored me!
Four 175 Watt panels, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.
Ohm's Law: Amps = Volts / Ohms
Power Formula: Watts = Volts * Amps