12v or 24v panel?

[DCfleetwood]

I'm going to install a 400W system on my motorhome and I've been trying to decide which panel to use, two 200w 12v panels or two 200w 24v panels with a victron smart solar mppt controller of course. I've read that a 24v panel is more efficient in low light conditions and may be more effective as I will not be there to watch what's going on. Is this correct? I'm really just trying to keep the batteries charged while parked and only running the refrigerator on propane. We are fulltimers and visit kids for 2 to 3 weeks at a time. I'm new to this and want to do it right, thanks for all replies in advance!

 

[chrisski]

I'm going to install a 400W system on my motorhome and I've been trying to decide which panel to use, two 200w 12v panels or two 200w 24v panels with a victron smart solar mppt controller of course. I've read that a 24v panel is more efficient in low light conditions and may be more effective as I will not be there to watch what's going on. Is this correct? I'm really just trying to keep the batteries charged while parked and only running the refrigerator on propane. We are fulltimers and visit kids for 2 to 3 weeks at a time. I'm new to this and want to do it right, thanks for all replies in advance!

IME there is so little power put out at the low light conditions you won’t notice any change in production.

There’s no such thing as a 12 volt or 24 volt panel. What is the panel specs?

You may get a marginal better voltage loss from the higher voltage panel.

Edit: for an RV build where you often are dealt a parking space and can’t control shading, I’ve found the more panels in parallel the better.

 

[DCfleetwood]

I know that even though they say 12 or 24v they actually produce more than that, hence the need for the controller.

 

[John Frum]

We are fulltimers and visit kids for 2 to 3 weeks at a time.

Does this have any design impact?

 

[DCfleetwood]

Just a timeline of how long the unit is parked for to keep batteries fully charged.

 

[John Frum]

Just a timeline of how long the unit is parked for to keep batteries fully charged.

How will the batteries be charged the rest of the time?

 

[DCfleetwood]

On board systems, alternator while driving, inverter/charger while plugged in, and generator for a backup (last resort)