Upgrading 10w solar panel warning

[ua40j]

I upgraded my 10w maintainer solar panel with a 50w panel. I wired it in direct replacement of the 10w.

Before starting, I inspected the wiring and found that it would take the additional load in both voltage and amperage (wire gauge was big enough). I did not install the charge controller that came with it.

The panel worked for 6 months until the 'Solar charging when lit' light went out.

I pulled the panel yesterday and found that Winnebago had built what appears to be their 10w 'charge controller' into the board next to the charging light. And I had fried the 2 resistors on that board.

Bypassing the toasted resistors put the solar panel back in operation (the light still won't work, but I measured at the battery). Now I need to find replacement resistors and get out my soldering iron and one very big magnifying glass to fix the board.

There had been discussion previously about upgrading and I wanted to let everyone know the result. I still believe that the 10w can be replaced directly, but I would limit myself to 30w (or 16v output versus the 17.2v I had) now that I know about the board-based charge controller.

[John Hilley]

Quote:

Originally Posted by ua40j I upgraded my 10w maintainer solar panel with a 50w panel. I wired it in direct replacement of the 10w. Before starting, I inspected the wiring and found that it would take the additional load in both voltage and amperage (wire gauge was big enough). I did not install the charge controller that came with it. The panel worked for 6 months until the 'Solar charging when lit' light went out. I pulled the panel yesterday and found that Winnebago had built what appears to be their 10w 'charge controller' into the board next to the charging light. And I had fried the 2 resistors on that board. Bypassing the toasted resistors put the solar panel back in operation (the light still won't work, but I measured at the battery). Now I need to find replacement resistors and get out my soldering iron and one very big magnifying glass to fix the board. There had been discussion previously about upgrading and I wanted to let everyone know the result. I still believe that the 10w can be replaced directly, but I would limit myself to 30w (or 16v output versus the 17.2v I had) now that I know about the board-based charge controller.

I would thnink that those are diodes to keep the panel from discharging when dark. I would use the charge controller that came with the panel. An LED with current limiting resistor should work to replace the "Charge Light"

[two2go]

FWIW, I also replaced a small solar panel with a 50w panel on my NRV Dolphin using the factory wiring. There was no charge controller originally. The new panel has kept the batteries up over this winter. Haven't seen how much it will help dry camping yet. Hope yours works out.
Here is a picture of the way mine was wired in case it might help. I put a charge controller in place of the diode between the LED indicator light and battery.

[TBI]

Those are diodes on the board. There should be three of them in series. They create a 1.8 volt drop (.6volts each) for the LED to get a voltage from. I don't remember what diodes were used so I don't know the current rating but I would remove it and install the controller that came with your new panel.

[ua40j]

Thanks all for the ideas and suggestions. The led indicating solar charging is in the OnePlace which is also one piece. These diodes are built into a circuit board that also provides voltage readings for the batteries.

Bypassing these diodes is not that simple. If someone has a good schematic of this circuit board that would be great. The electrical diagrams in the Winnebago website don't go to that level of detail.

[bruceh]

I would have felt more comforatable using the charge controller that came with the panels. In my last motor home, I had a 50w panel (installed by a previous owner) that kept boiling the water out of the batteries. I was new to RVs at the time and it took me a while to figure out what was going on. A Siemens charge controller solved the problem.

Since a 10w panel has so little current, I would wonder what kind of controller was in there. The schematic appears to be none, just a protection to not discharge the battery.

Good luck

[John Hilley]

Quote:

Originally Posted by ua40j Thanks all for the ideas and suggestions. The led indicating solar charging is in the OnePlace which is also one piece. These diodes are built into a circuit board that also provides voltage readings for the batteries. Bypassing these diodes is not that simple. If someone has a good schematic of this circuit board that would be great. The electrical diagrams in the Winnebago website don't go to that level of detail.

Check out this One Place Solar Charge LED thread

[ua40j]

Thanks, John. I had totally forgotten about that thread. Got some work to do.

[two2go]

I mentioned above that I installed a charge controller in my circuit. After reading about the Winnebago controller, I have to wonder how precise or sophisticated they are. This is the one I used http://www.morningstarcorp.com/en/sun-guard - fairly inexpensive and has some good features; for example, temperature compensation and pulse width modulation. Just a suggestion, especially if upgrading the solar to 50 watts. More wattage would require a larger capacity controller.

[ua40j]

I don't think there is a charge controller in the Winnebago setup. It's just a blocking diode arrangement with led power tap that lights the led and prevents the solar panel from discharging the batteries at night.

I'm going to install my charge controller which came with the solar panel....but I also need to repair the diode arrangement. Or figure out some other way to get the light to work.

[two2go]

Sorry to keep interjecting here. I suggest checking the mfgr. specs for your new controller. If it has any enhanced features at all, it probably has built in discharge blocking. A series of diodes in addition to the charge controller may not be desirable and will reduce your effective voltage from the panel a bit. I'm not guaranteeing it, but suggest you consider bypassing the Winnebago board and just wire the LED in before the controller. If you refer back to my diagram, that is the factory set-up with a 10w panel. I removed both diodes and put the new controller in place of the lower diode. The LED is in the circuit as shown hooked directly to the +12v (actually up to 22v) from the roof. The LED is lit when there is any daylight, and dark at night. The fact that it does go out shows there is no +12v coming back through the controller from the battery.
Actually, my controller has an indicator LED also, but I mounted it behind my control panel, so I use the original LED on the panel. This setup has kept my batteries prime charged all winter in storage and is working great.

[Paul T]

Hi two2go, what part of the country was your RV in storage? I'm just curious in that you said the 50w solar panel was able to keep your batteries up in storage this season. Are you north or south of Denver's latitude??

[ua40j]

Two2go...keep injecting.

I have the same controller you have. Thanks for the inputs.

[two2go]

Quote:

Originally Posted by Paul T Hi two2go, what part of the country was your RV in storage? I'm just curious in that you said the 50w solar panel was able to keep your batteries up in storage this season. Are you north or south of Denver's latitude??

Coach stored at about 39'-30" N. Baseline Road in Boulder is 40'.
I'm hoping to get reasonable recovery charge this summer while dry camping. I've not had good luck with this power hungry coach before. One day and night and the refer was complaining and had to run the engine for over a half hour to get enough juice to make it another night. The engine alternator charged faster than the generator. Of course, more panels would be good, but the budget said "no".
My original little panel never worked. The 50w is a champ.