Need Help 15w Solar Charger

System · May 2009

I am hopeing someone can help get me started in the right direction. I have a 15 watt 12 volt solar battery charger made by Sunforce. I also have their 7 amp charge controller. The instructions and trouble shooting guide leave a little bit to be desired. I have installed the charger on my 2007 Glufstream Class C motorhome, Model ULTRA. The problem I am having is this. When I hook the panel to the controller, and the battery. The controller seem to work, the lights come on and indicates it is charging. When I hook the (-) wire on the coach to the battery, the controller stops working. All the lights go off.

I am getting 23 volts with an open circuit from the panel, and 22 volts at the leads before I hook them to the battery.
Sunforce customer service advised they had never heard of such a problem, as did Camping World.

BB. · May 2009

Re: Need Help 15w Solar Charger

I can't get to their website--so I cannot read the manual (may be of little help anyway).

From the Amazon website, a couple of comments:

Once I finally figurd out that it was wired incorrectly internally, the controller works as it is supposed to. The positive and negative wires were reversed and was driving me crazy trying to get it working. Finally I reversed my wiring an it worked.
...
Beware though, in order to test the actual output voltage, you must apply a load on the battery end of the controller BEFORE. Failing this, the output can register volts as high as 20 volts !!! Apparently applying an actual load causes the controller to output the correct voltage range

So--a couple of suggestions from above---

-Bill

PS: Try connecting the battery to the controller first, then connect the solar panel (or connect the controller to the battery with the panel in the dark or covered with a piece of cardboard). Some controllers internally program themselves based on the battery voltage (before the panel is connected--though I doubt that this controller is self programming. should be just hardwired to 12 vdc).

The high voltage of 20+ volts is the normal Voc (Voltage open circuit) for a typical "12 volt" solar panel (panel voltage needs to be higher than battery voltage to charge the battery).

mike95490 · May 2009

Re: Need Help 15w Solar Charger

Does a 15W charger, on a large RV battery, really need a controller ?
( does the panel have a diode in it? )
Does the battery ever get water level checked ?

Cariboocoot · May 2009

Re: Need Help 15w Solar Charger

I agree with Mike: 15 watts divided by 12 volts is 1.25 amps (nominal). Who needs a 7 amp controller for that? It does sound as though the unit is defective, though.
That panel won't be much for charging a battery, but it may be enough to negate self-discharge.

System2 · May 2009

Re: Need Help 15w Solar Charger

Website is http://www.sunforceproducts.com/prodinfo/manuals/SunforceSolarManEng.pdf

As far as the controller, I don't think it's nessasarry for the 15 watt panel, but I hope to upgrade with more panels, once I get this little problem worked out.

Thanks for all the suggestions, I'll give them a try and let you know.

Bill W.;)

System2 · May 2009

Re: Need Help 15w Solar Charger

Thanks again everyone for your suggestions and Help. As it turns out it was not a defective controller. Just a defective electrician.

In back tracking the problem. I had used staples to secure the wires from the solar panel as they ran through my motor home. I found that I had pierced the wire at one point. Once I removed the staples it works great.

Works so well I added 4 more panels and am up to 75 watts.

Thanks again.

Bill W.

homerramirez · May 2009

Re: Need Help 15w Solar Charger

You already spent the money, consider the watt x sq. ft, a 130w panel will use less space than 8x15 watt panels...:cool:

dwh · May 2009

Re: Need Help 15w Solar Charger

homerramirez wrote: »

You already spent the money, consider the watt x sq. ft, a 130w panel will use less space than 8x15 watt panels...:cool:

Yes and no. I have a "camper van" I bought recently. It doesn't have an a/c on the roof, but there is a 14" square vent on the roof, just a bit to the rear of center.

The fiberglass top slopes inward toward the center, and then as you can see in the pic, it has an additional "step" in it. That makes the roof too narrow for me to put a Kyocera 135w (60"x26") sideways, and too narrow for me to put two of them side by side as well.

I can squeeze a single 135w on in front of that vent, but not behind it. However, I could probably take one of those harbor freight 3x15w kits and put one panel to the rear of the vent, and one on either side of it.

So at least in the case of this little camper, smaller panels are all that will fit. Sure, a bit more $ per watt, but if the cheaper per watt panel won't fit, it's useless.

mike95490 · May 2009

Re: Need Help 15w Solar Charger

What's the panel's wind speed spec, or will they be up, only when parked ?

dwh · May 2009

Re: Need Help 15w Solar Charger

mike90045 wrote: »

What's the panel's wind speed spec, or will they be up, only when parked ?

What? Who? Me or the OP?

mike95490 · May 2009

Re: Need Help 15w Solar Charger

original poster - the RV top panels.
> What's the panel's wind speed spec, or will they be up, only when parked ?
Are the panels Weather proof, or rain resistant ?

Need Help 15w Solar Charger

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