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dc73 · 01-21-2021, 11:50 PM

I have the factory 10w solar panel on my 2005 Adventurer. There is a charging light on the instrument panel that is lit when charging is happening. I am trying to figure out a way to check what current is coming in from the panel. I recently installed the Renogy battery monitor, but with the solar charging light lit, I don't see any +current on the monitor. I know that 10w is very low (10w = .83 amp), but the monitor seems to be pretty accurate and certainly shows numbers that low, seems like it should be showing. How can I measure whether the solar is really charging?

cruizerEd · 01-22-2021, 06:37 AM

Yes 10W is .83 max. Unless the panel is new, you have a quality controller, the wiring and connectors have no significant resistance, the panels are clean, fairly cool, in direct sunlight, and the sun is 75 degrees or higher your not going to see 10W. So that panel is how old? It is winter and the sun is low. So now we're looking at .4 ams or so. That could be the issue. Bottom line 10W working isn't much different than 10W not working.

Unplanned Tourist · 01-22-2021, 06:57 AM

That factory solar panel is for the chassis battery, not the house batteries.

BillJinOR · 01-22-2021, 07:32 AM

A 10 watt panel is a sales gimmick and has no useful purpose other than to keep a full battery with no load full. The one I had on an old MH was wired to the chassis battery with no controller for that “purpose “ . The light was wired in line to come on if the panel was producing any power.
You could go up on the roof and tap the lines to check there.

dc73 · 01-22-2021, 08:59 AM

Quote:

Originally Posted by Unplanned Tourist

That factory solar panel is for the chassis battery, not the house batteries.

If my manual can be trusted, it would disagree...

dc73 · 01-22-2021, 09:03 AM

Quote:

Originally Posted by BillJinOR

A 10 watt panel is a sales gimmick and has no useful purpose other than to keep a full battery with no load full. The one I had on an old MH was wired to the chassis battery with no controller for that “purpose “ . The light was wired in line to come on if the panel was producing any power.
You could go up on the roof and tap the lines to check there.

My manual states that it is for the house batteries, see my response to another post. It still might be a bit of a sales gimmick. I wonder if I could add a modern aftermarket model and use the same wiring? I pulled the panel and checked voltage at that indicator light, but it was getting a full 12.5v so that told me it was just being triggered somewhere else, and then the main system was sending regular voltage to the light itself.

dc73 · 01-22-2021, 09:05 AM

Quote:

Originally Posted by cruizerEd

Yes 10W is .83 max. Unless the panel is new, you have a quality controller, the wiring and connectors have no significant resistance, the panels are clean, fairly cool, in direct sunlight, and the sun is 75 degrees or higher your not going to see 10W. So that panel is how old? It is winter and the sun is low. So now we're looking at .4 ams or so. That could be the issue. Bottom line 10W working isn't much different than 10W not working.

Thanks - yes it is the factory 2005 model.

BillJinOR · 01-22-2021, 09:18 AM

I don't believe that it has a controller ,I never tore into my 04 Winnie but it didn't seem to ... thus the statement it glows brighter because as the panel produces more volts , the light gets brighter. If you want too add more solar I would run new wires The 10watt panel wires are small, and put in a controller.

Persistent · 01-22-2021, 11:02 AM

Using the old wire for a bigger system is likely not useful. Wire for 1 amp could be very small. A 150 watt panel would need at least 14 gauge wire. A pair of 150's would need 10 gauge wire.

Testing the directly connected panel by measuring voltage will be limited. You should see the battery voltage.

Disconnect the solar panel before measuring voltage. Voltage higher than the battery voltage would mean it is charging, however small. Measure current directly to see how much.

I wish you good luck and happy trails ahead!

John Hilley · 01-22-2021, 12:57 PM

You could probably use the existing wiring for up to a 50 watt replacement panel. If fused it would have to be changed to a larger fuse.

hclarkx · 01-22-2021, 01:12 PM

From my experience, the problem you are having seeing the charge current is the result of the monitor being digital. Current below a certain threshold is down in the noise (and a digital last-digit problem) and will not register correctly. Even a high end battery monitor like the Victron BMV-712 can't see very small currents and may need to have it's default 0.1 amp threshold raised to avoid inaccurate SOC readings. BMS that include SOC monitoring usually are set to not see under a half to 3/4 amp.

The 10W panel will likely never give you a full 10W and will do close to 10W only for a few hours in June. More typically it will top out at 7-8W and likely never hit 5W in the winter. So it's likely you rarely get over about a half amp and that may be below the sensitivity threshold of your battery monitor.

bobmac · 01-22-2021, 02:49 PM

dc73 - I suspect the output is near zero. Solar panels deteriorate with time and yours is 16 years plus. The 0.83 amps is really just a theoretical calculation of what the maximum output is at 100 percent efficiency. I installed 4 100 watt panels in 2013 and have never had battery issues since - in part due to being stored outdoors with no trees. Suggest you go that route - prices are very reasonable and installation is a diy job if you are handy. I get typically 25 plus amps on a bright summer day and they maintain the batteries year round so your batteries will last longer.Good luck,

dc73 · 01-23-2021, 02:17 PM

Thanks to all who commented. Most likely will do a solar upgrade at some future point.

mcroadrunner · 01-24-2021, 10:07 PM

Here is a thought. Take a cardboard box big enough to cover your solar panel & hang a 100w bulb in the top. Now where your charge wires go to battery. With a vom meter checking for current (series) to battery & voltage. Then unplug light in box to simulate darkness. The difference in readings should tell if solar charge system is working. And yes they are for the house battery. Not the chassis battery. Unless previous mechanic connected wrong.