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Author Topic: IS THE SOLAR PANEL WORKING?  (Read 510 times)

LARRY L

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IS THE SOLAR PANEL WORKING?
« on: May 08, 2009, 08:13:28 PM »
How can you tell if a solar panel is actually putting out the right watts? The glass is cracked on one of mine and I am not sure if it is working properly. I have a 5 and a 15 watt panel.

JerArdra

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  • Posts: 1812
Re: IS THE SOLAR PANEL WORKING?
« Reply #1 on: May 08, 2009, 09:40:29 PM »
Try this.  Go up on the roof and when the BROKEN panel is in the high-noon sun use a voltage meter to read the voltage on it's two outbound wires.  Then do the same on a GOOD panel.  Obviously if they are equal all is well.

JerryF
JerryF  ;D  ;D

Gary RV_Wizard

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Re: IS THE SOLAR PANEL WORKING?
« Reply #2 on: May 09, 2009, 06:04:50 AM »
A 5W panel puts out so little electricity that it is probably irrelevant whether it is working. Even the 15W will only have one amp in peak sun.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

DonTom

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Re: IS THE SOLAR PANEL WORKING?
« Reply #3 on: May 09, 2009, 07:38:10 PM »
How can you tell if a solar panel is actually putting out the right watts? The glass is cracked on one of mine and I am not sure if it is working properly. I have a 5 and a 15 watt panel.

Get a 12 volt automotive lamp. Connect direct to the solar panel when in direct sunlight. IOW, IIRC, a 1157 automotive lamp uses three watts for the tail light and 27 watts for the brake light. If you know the wattage of the bulb, use it for your watt meter. That's the easy way and all I would do.

But if you want exact numbers, measure the voltage (expect less than 12 VDC, but the higher the better)  across the 12 volt lamp with the lamp connected to the solar. Then measure the current in series with the lamp. Voltage times amps= will be your exact watts. Do not expect to get 15 watts from a 15 watt solar panel unless conditions are 100% perfect for sunlight and temperature (solar panels do NOT like heat). Consider anything close as being okay. Use a lamp at or slightly above the watt rating of the solar panel or else you will only get the wattage of the load instead of what the solar panel is really capable of.

A simple test is getting any 12 volt lamp out of your RV used for inside lighting. If your 15 watt solar lights it  up noticeably better  than the five watt solar panel, assume the 15 watt is working fine.

Your non-load voltage from the solar panels might be around 20 VDC. This means almost nothing but check it first anyway, if you have a VOM handy. If that ain't there, don't even waste your time with the above test.

-Don- Reno, NV

« Last Edit: May 10, 2009, 05:35:03 AM by DonTom »
-Don-   AA6GA

2000 Fleetwood Tioga 24D, 7.4L

Auburn, CA or Cold Springs Valley, NV or  Reno, NV

 

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