Two Controllers charging same battery?

[WaltAllen]

Question from a relatively new solar guy. I want to double my panels from 4 to 8, and the panels will have different voltage and amps.
I plan to get a second MPPT controller for the second 4 panels and feed the 24 volt output into the same 690 AH battery bank. Will the two controllers interfere with each other in some way?

 

[rmaddy]

Unless the controllers support some sort of communication between them (Victron, for example) then the two controllers won't know anything about the other and they don't really need to. Just setup up both with the same battery and charging settings and it will be fine.

The only thing you need to account for is the combined charge current. You want to make sure the combined charge current of both controllers doesn't exceed the max charge current of your battery bank. This is true for all charge sources you may have in your system.

 

[ghostwriter66]

technically you will be OK ... they will not interfere and both will at independent ... the battery will stop charging at the limit the highest charger is set at (whichever chrger)... and start charging at the lowest limit (which ever charger)...not the idea way -- but it will work ...

 

[DThames]

Following what Ghostwriter66 said.....Don't be surprised when the battery is getting to a higher state of charge that one charger's current drops to zero. This is normal because it is managing the current based on what the voltage is doing. When one charger's output is strong enough to hold boost level or hold float level, the other charger will back off, often completely to zero. That is normal.

 

[WaltAllen]

Thank you all. That was just what I wanted to hear!