First let me say thanks to everyone who replied in my previous thread 'Need help in buying a meter. So yesterday I bought a multimeter.As some of you may remember a neighbour of mine gave me a brand new still in the box 40W solar panel. Here is the specs of the 40W solar panel.Up to 40WattsOpen circuit volt. 21.5vMax power volts. 17.1vShort circuit current. 2.3AToday a few minutes ago 'noon time' I tested my solar panel and here is what I got.Volts: 10.07 Amps: 1.68 Question: Does this sound right? Is the volts/amps enough to change a 12v battery?Thanks

Nope. You need at least 13.5VDC to charge a battery. Sounds like your free by has some bad cells.

Try aiming directly at the sun, mid day, when measuring. You should meter 17 to 21V and the Amperage sounds a bit light, should be seeing over 2 amps, if your battery is low in state of charge. Try again, in direct sunlight, mid day, around noon, and get back to us.In the future, get in the habit of listing the number first, then the unit of measure.

Ok? Question on my process. I connected the multimeter probes directly to the controller output, is that correct? Will try again tomorrow got some errands to do.Thanks again for the replies.

icanon wrote: I connected the multimeter probes directly to the controller output, is that correct? Solar panels don't have controllers on them. If you mean that box on the back, that's simply a junction.I agree, it sounds like a defective panel, provided your meter was set to the proper DC voltage range.

2oldman wrote:icanon wrote: I connected the multimeter probes directly to the controller output, is that correct? Solar panels don't have controllers on them. If you mean that box on the back, that's simply a junction.I agree, it sounds like a defective panel, provided your meter was set to the proper DC voltage range.The part I was talking about says on it, 7amps Solar Controller, so I guess it's called a controller. Will take photos of process tomorrow.

Part 2 Need help in buying a meter. | Good Sam Community

24 Replies

2oldman
Explorer II
Sep 27, 2015
icanon wrote:
I connected the multimeter probes directly to the controller output, is that correct?
Solar panels don't have controllers on them. If you mean that box on the back, that's simply a junction.

I agree, it sounds like a defective panel, provided your meter was set to the proper DC voltage range.
icanon
Explorer
Sep 27, 2015
Ok? Question on my process. I connected the multimeter probes directly to the controller output, is that correct?

Will try again tomorrow got some errands to do.

Thanks again for the replies.
NinerBikes
Explorer
Sep 27, 2015
Try aiming directly at the sun, mid day, when measuring. You should meter 17 to 21V and the Amperage sounds a bit light, should be seeing over 2 amps, if your battery is low in state of charge.

Try again, in direct sunlight, mid day, around noon, and get back to us.

In the future, get in the habit of listing the number first, then the unit of measure.
donn0128
Explorer II
Sep 27, 2015
Nope. You need at least 13.5VDC to charge a battery. Sounds like your free by has some bad cells.

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Part 2 Need help in buying a meter.

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