Dual controller to different voltage systems

gshapow

I have a 12V system consisting of a single 12V battery and a 24V system consisting of 2 12V batteries in series. I have an EPIPDB-20 dual battery charge controller and a 130 watt solar panel putting out 39 volts in full sun.

I tried connecting battery 1 output of the controller to the 24V system and battery 2 to the 12V system. The unit was advertised as auto sensing for 12V or 24V. The controller saw the 12V battery and began charging it. It saw the 24V system as "OPEN". I assume then that I cannot use 2 different voltage systems on the same controller.

Can I connect battery 1 from the controller to one of the 2 series batteries in the 24V system and battery 2 to the other battery in the 24V system? The single 12V battery could then be connected to its own controller.

Thanks for the help.

George

Cariboocoot

Re: Dual controller to different voltage systems

Welcome to the forum.

The thing about controllers that are designed to charge two batteries is that they are designed to charge two of the same Voltage batteries. Whereas it will auto-sense 12 or 24 Volts once it is set that's it until it gets reset (usually by disconnecting the battery Voltage long enough to zero the memory).

If you use the dual controller for half of the 24 Volt system and the separate 12 Volt system then connect another controller for the other half of the 24 Volt system the 24 Volt system's charging is bound to be unequal. But if you are going with two controllers, why not let one handle the 24 Volt and the other handle the 12? I know: you won't be making use of the dual battery ability, but on the other hand it will work.

gww1

Re: Dual controller to different voltage systems

I am a newbee so take what I say with a grain of salt. What are you trying to do.
1. run 12 volt loads off of a 24 volt battery bank?
2. Trying to not have to get another battery?

If you need to run 12 volt loads from a 24 volt battery bank just get one more battery so you have four batteries. Then get a dc to dc converter to run the 12 volt stuff.

If you are just trying to use your solar panel to charge three batteries, go to a 12 volt system and paralell the batteries.

Again I am new so if someone out there could comment on this it would be great.
good luck
gww

Cariboocoot

Re: Dual controller to different voltage systems

gww;

I believe he's trying to charge two systems of different Voltages from one array.

Your suggestion of using the converter to replace the 12 Volt system may be viable. Otherwise without more details it's hard to say what the options are, much less the best one.