24v solar panel hooked to 12v system...Would it blow up?

[wilfor03]

  If I hook up a 24v solar panel to a 12v system, what would happen?  Would it even charge? I have 140w's of panels now (all 12v) and just getting started......just really curious on this one???    Bill

[DamonHD]

Depends entirely on the details of your 12V system, but quite likely yes, IMHO.

Most 12V/car devices don't like to see much over 15V, so if for some reason your controller or battery failed to hold it down (and it might have an open circuit voltage of up to 40V), then *pooof* out comes the magic smoke.

On the other hand, if you have a smallish 24V panel charging a big 12V battery via a robust but non-MPPT controller you'll just be throwing away more than half the available energy since PV behaves as a constant current source under heavy load.

Rgds

Damon

[ghurd]

Many 12V series solar controllers are not rated to handle the 40+ open volts they will see from a 24V panel when the battery reaches regulation voltage.
G-

[wpowokal]

Bill, Is this a problem you have or just a theory question? Others have answered your theory, my assumption as you say your all your panels are 12V, but should you have a 24v panel it would be worth checking in the terminal box as many panels are made up of two strings of half the rated volts in series, separated by diodes.

allan

[thinkthink]

If you have 24v applications,but want to use a 12v control system,you can use a transformer to reduce the voltage,send it to the control system,again use a transformer to increase the voltage.

[TomW]

If you have 24v applications,but want to use a 12v control system,you can use a transformer to reduce the voltage,send it to the control system,again use a transformer to increase the voltage.

thinkthink;

This is WRONG in the context of Direct Current applications.

Transformers only work on AC.

A solar panel puts out DC.

Thanks for trying.

Tom

[southpaw]

Hi Wilfor03
Many solar setups use higher voltage panels than the battery capacity, in order to reduce conductor size and line losses.
I have 3 200 watt 12v panels in series with over 60 VOC feeding a 12v battery bank through an MPPT charge controller.
This allows me to use 1/3 the wire size as it is over 100 ft. from panels to batteries and increases the efficiency of the
charging system and the extra cost of the charge controller was almost completely offset by the reduced cost of the
conductors and the increase in efficiency was almost equal to getting a free panel.

southpaw

[wilfor03]

I appreciate the feedback there Southpaw.......almost really understand it too!!! LOL......I was watching 24v panels on fleabay and was wondering about the initial question of "um, Could I do that?" Thanks for all the info, gang....Bill

[tecker]

24 volt panels in the 60 watt range have a voltage of of around 30 volts too high for 12 volts . However 24 volt battery bank is easily configured for 12 volt usage.