First time testing solar - volts but no amps

[Maggie Belle]

I have two 180 w solar panels - no loads yet, just testing them for the first time. I have a clamp meter. Voltage tested perfect on both. But I'm getting nothing for amps. I am pretty sure I'm using the clamp meter correctly as I was able to measure the amps on my maxx fan. What am I missing? Do I need a load? I thought I saw videos of people testing without a load.

 

[Bob B]

Were the + and - leads connected together when using the clamp meter .... this would tell you the short circuit amperage.

It's normally not a good idea to short + and - connection, but in the case of the solar panels, they are designed for that.

Oh.... and make sure the clamp is only connected around one of the leads.

 

[RCinFLA]

Many folks feel uncomfortable about shorting out PV panel but it will not hurt them. There may be some initial sparks when you first touch wires together. After shorting leads then check Isc current with clip on ampmeter.

If less then 10 amp panel, you can use a DVM meter 10A current measurement port.

The measured Isc will be based on given illumination at time of measure, not necessarily the panel specs Isc taken at controlled temp and full sun illumination.

 

[chrisski]

Hard to see in the pic, but I do short the cables as mentioned:


Since these panels are Anderson Powerpoles, this is the wire loop:

MC4 might be able to plug together, but they can be tricky to unplug without the correct tool.

 

[Maggie Belle]

I'm sorry I

Were the + and - leads connected together when using the clamp meter .... this would tell you the short circuit amperage.

It's normally not a good idea to short + and - connection, but in the case of the solar panels, they are designed for that.

Oh.... and make sure the clamp is only connected around one of the leads.

Thanks! I see a couple people mentioned this. I don't know how to do it, even though I'm seeing an image below. Can someone explain it to me?

 

[chrisski]

Here’s a video:

 

[sunshine]

I have two 180 w solar panels - no loads yet, just testing them for the first time. I have a clamp meter. Voltage tested perfect on both.

Skip the amp test. Use the amp rating on the label. Your panels are going to be ok.
If the panels look ok and Voc approaches label Voc then seldom is there a amp problem other than bad wiring or crimps and often these are intermittent so your amp test may miss it anyway.

 

[740GLE]

I have a similar uni-t meter, when measuring current did you make sure it was on DC? It defaults to AC current, so each time you have to select DC.

Also IMO short circuit current is pretty pointless.

 

[Maggie Belle]

I have a similar uni-t meter, when measuring current did you make sure it was on DC? It defaults to AC current, so each time you have to select DC.

Also IMO short circuit current is pretty pointless.

I did change it to DC current, as I changed it to DC volts when I used it for Volts. I tested the Maxx Fan current and it worked good. I'm confused. From some of these messages I was thinking short circuit current was the only option to test a solar panel without a load (for current) Thanks for the input as I learn.

 

[Maggie Belle]

Here’s a video:

I did see this video before I tested my panels. One difference is that he doesn't have a clamp meter. Does that matter? I didn't see him short the wires in this video. I'll look again.

 

[chrisski]

I thought you had a multimeter that could test amps. That video did not cover a clamp meter.

 

[Maggie Belle]

I thought you had a multimeter that could test amps. That video did not cover a clamp meter.

I have a clamp meter that tests amps. https://www.amazon.com/UNI-T-Digita...t=&hvlocphy=9012189&hvtargid=pla-825340133445

 

[chrisski]

I have the same clamp meter. That does not have a way to measure amps with the leads, only the clamps.

If the panels have MC4 connectors, you could simply connect them together, but they also lock once connected and without the special tool its really tricky. So a little practice would be good with the panel covered.

I see that you have a 180 watt panel. Depending on the output, that could be too much for a normal multimeter to measure. Most multimeters I’ve used have a 10 amp fuse. Without seeing the specs on that panel, I think there’s enough amps to blow that fuse. So, you may have to use the clamp meter you have.

If measuring amps is too difficult, I’d skip the amp test, but continue to test. I’d hook a SCC to a battery and set it not to out out to much amperage. My Victron has an option to limit amperage. Once the SCC was programmed, I’d attach a panel and check the SCC display to see if it is pushing amps or gives a battery charge indication. If it is charging, you can put the clamp meter around the panels wires and you should see the same thing.

 

[Maggie Belle]

I have the same clamp meter. That does not have a way to measure amps with the leads, only the clamps.

If the panels have MC4 connectors, you could simply connect them together, but they also lock once connected and without the special tool its really tricky. So a little practice would be good with the panel covered.

I see that you have a 180 watt panel. Depending on the output, that could be too much for a normal multimeter to measure. Most multimeters I’ve used have a 10 amp fuse. Without seeing the specs on that panel, I think there’s enough amps to blow that fuse. So, you may have to use the clamp meter you have.

If measuring amps is too difficult, I’d skip the amp test, but continue to test. I’d hook a SCC to a battery and set it not to out out to much amperage. My Victron has an option to limit amperage. Once the SCC was programmed, I’d attach a panel and check the SCC display to see if it is pushing amps or gives a battery charge indication. If it is charging, you can put the clamp meter around the panels wires and you should see the same thing.

Thanks for taking the time. This all makes so much sense and I've definitely learned something here. I may skip connecting the wires as I don't have the tool. Volts were perfect. I will perform the SCC test as soon as I figure that out