Solar Panel Wiring


I’m half way through converting my van, the electrics are done and for the most part working.

I have x2 100w Renogy solar panels with a 50a DC-DC Battery Charger, the alternator charger is working fine but I’m getting nothing from the solar side. I’ve tested the system with a multimeter and I’m getting a complete circuit from all element. The only strange thing is that it only shows as a complete circuit when I connect the positive of the multimeter to the negative on the solar circuit and positive on the multimeter to negative in the solar circuit. The multimeter is just a connection to complete the loop so the way around they are connected should be indifferent, no?

Only questions I’m left with is can power only flow through a solar panel in one direction? If so, is there a possibility that the tails on my panels have been manufactured around the wrong way. I’m included to switch the positive and negative at the DC-DC charger so see if it solved the issue but don’t want to do this if it could cause damage?

Any suggestions would be much appreciated! I’m impatient to wait for Renogy but always have this as an option I guess.


I do not know much about the dc to dc chargers, but I do not see why you would run your solar panels to it. Do they not run directly from the charge controller to the batteries? Or is it some type of combination device?

If the charge controller is not hooked up to the batteries and the solar panels are hooked to the controller you could have fried it.

1st. What is All Element?
2nd. your using the meter wrong if you are checking Voltage running the meter in series in your circuit, series for current(amps) parallel for voltage. I suggest finding a block diagram and recheck your wiring. Are you running your panels in series or parallel? What is the voltage at the input of the controller from the panels? Output of controller?
Yes you can damage components by connecting with the polarity incorrect. Yes current only flows one way thru panels. They also have a blocking diode so the current dosent back flo into the panels at night.
Like the above post, why are you running it to the dc dc?

I think he’s just saying the charge from the dc/dc alternator charging to batteries is working but the solar charging to the batteries is not. If he’s got the connections correct at the solar controller from the panels:++&-/- but no current flowing from the controller to the batteries it’s either not programmed properly or it’s not working- could be a blown fuse. The controller should display issues with the circuit or if it’s actively charging.

++ - - would be a parallel circuit = 12 volt system
± ± would be a series circuit =. 24 volt system
± ± ± would be a series circuit = 36 volt system

I’m not going to get into combination series/ parallel circuits, too confusing.
A good tip: Voltage goes up……Current goes down. Which is a good thing…smaller gauge wiring.
Voltage is tested in parallel
Low Current is tested in series
High current is tested with clamp style amp meter or a shunt…check your meter for max current or you will fry it.