# Adding 24v Panels to 12v System



## Ozark_Bro_Jerry (Oct 30, 2013)

I've had a 12v solar system for many years and everything works fine. I just added a 24v panel through a "Solar 30" charge controller. When I have the 12v system turned off, the 24v panel and controller word great; however, when I turn the 12v system back on, the reading on the Solar 30 goes to zero amps. Anybody got any ideas?


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## Fire-Man (Apr 30, 2005)

Ozark_Bro_Jerry said:


> I've had a 12v solar system for many years and everything works fine. I just added a 24v panel through a "Solar 30" charge controller. When I have the 12v system turned off, the 24v panel and controller word great; however, when I turn the 12v system back on, the reading on the Solar 30 goes to zero amps. Anybody got any ideas?


Are you hooking the new 24 volt set-up to the old 12 volt set-up? Explain how you got it hooked up. That will help.


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## wy_white_wolf (Oct 14, 2004)

Is the "Solar 30" a PWM or MPPT controller?

Is the 12V controller a PWM or MPPT?

Do you have them both set to the same battery type?

What are the bulk, absorb, and float voltages set at? What was the state of charge of the battery?

Sounds like you have a 12V PWM controller (con1) and the Solar 30 is an MPPT type (con2). If the con2 happened to be in absorb or float mode when con1 was hooked up it could easily take the voltage above the setting of con2. That would make con2 reduce the amperage until the voltage comes back down within it's abortion or float range. If it doesn't come down con2 will terminate charging as it does not want to overcharge the batteries.

You could also have 2 PWM controllers, but the on/off voltages are different. for example con1 has settings of off- 14.4V on - 13.8. Con2 has 14.2 and 13.2 settings. When charging they will both work as long as the sensed voltage remains below 14.2. when it reaches 14.2 con 2 shuts down to cycle, but it never comes back on because con1 cycles at higher settings.


It is important to have both charge controllers of the same type and voltages set the same.

WWW


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## Ozark_Bro_Jerry (Oct 30, 2013)

Thanks for input White Wolf! It was a duh moment. I started looking at the voltage points as you suggested and the batteries were simply overvoltage; hence, the controller was shutting down.


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## Fire-Man (Apr 30, 2005)

Ozark_Bro_Jerry said:


> Thanks for input White Wolf! It was a duh moment. I started looking at the voltage points as you suggested and the batteries were simply overvoltage; hence, the controller was shutting down.


 What was the problem?


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## wy_white_wolf (Oct 14, 2004)

Ozark_Bro_Jerry said:


> Thanks for input White Wolf! It was a duh moment. I started looking at the voltage points as you suggested and the batteries were simply overvoltage; hence, the controller was shutting down.


Yep. When you have 2 different controllers on 1 battery bank one will usually become dominate when the bank is charged.

WWW


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