attaching multiple charge controllers

Re: attaching multiple charge controllers

Umm... Maybe.

The problem is that a second charge controller in series means the upstream MPPT Charge Controller needs to set its output something like 1-2 volts higher to allow for the voltage drop of the second controller. Also, the first Charge controller should be configured to not go into "float" voltage as the controller attached to the battery bank will be the one controlling the charging.

Backing up a moment--What is it you are trying to do? Better monitoring/logging because the first MPPT charge control does not have a (working) display?

For battery management/monitoring--I would suggest a Battery Monitor.

-Bill

Re: attaching multiple charge controllers

I would suggest not doing this... You will probably have more issues with trying to program the MPPT charge controller for a high output voltage and have to play a lot of games to get the whole thing to work at all--let alone work reliably.

Also, most MPPT charge controllers will not function if they are not connected to a battery bank for constant voltage to run their micro processor/electronics. You could start playing a game of placing a power resistor across the positive PV input to battery positive output on the PWM controller to power the MPPT charge controller--But even then the PWM controller turning on/off (PWM mode) will probably confuse the heck out of the MPPT charge controller.

A battery monitor+MPPT controller would be a much better solution--And will give you battery state of charge/other information that a charge controller cannot really do.

-Bill