Easy way to measure solar output (Amps)?

BFL13 wrote:

You first want to see what the panel is doing. For that take the Isc by disconnecting the panel from the controller's array side. Now put the meter across the two panel wires (ignore pos and neg, doesn't matter)

My solar setup is portable and I have a plug between the panel and controller. If I'm understanding this correctly, I can unplug the panel and place my meter across the plug prongs for a reading? This is new to me; I thought I had to place the meter in line. If I can use the meter to complete the circuit, taking the readings I want will be simple. It's getting dark here now, so I'll try that tomorrow. Thanks very much.

The suggestions about an inline dedicated meter would be very good. Unfortunately I elected to keep the system portable and outdoors, so any meter would have to be weatherproof.

rexlion wrote:
I did all of the above. I am getting "something" but it's not right.

That 1a might be ok or not--

You first want to see what the panel is doing. For that take the Isc by disconnecting the panel from the controller's array side. Now put the meter across the two panel wires (ignore pos and neg, doesn't matter) You will get some amps depending on how well the panel is aimed at the sun, etc. If it is a 4a Isc rated panel, you might get that much or a bit more or a lot less, depending on aiming and the amount of sunlight. Say you get 3a. (panel aimed right but sun low, eg)

Now you want to know how much of that 3a is getting to the battery. Connect controller to battery and array to controller in that order, but with meter in line with battery controller. Say it says 1a.

(You can't do this with lots of white clouds rushing by the sun changing the amps every minute. You need a time of sun in the clear so you have time to do all this.)

Now you can find out where did the 2a go missing? -- Batteries might be full so only take 1a, or wiring losses including connections.

With batteries low enough to accept the amps, the panel aimed at the sun will have the nearly the same Isc amps reading as you see at the battery

The Blue Sky 2512iX or 3024iL and IPN-ProRemote will readout amps in and amps out of the controller, as well as voltage, SOC, battery temperature, and AH from full.

Agreed! My TM2020 can tell me all about amperage, voltage, percent charged, etc. Way more than I typically want to know.

May I recommend a PERMANENT meter?

20-amp digital meters and shunts are very inexpensive, and not difficult to install in the solar controller wire. This way you know what the panels are doing for a living.

I did all of the above. I am getting "something" but it's not right.

Hi,

The battery terminals need to stay connected and you need to open the circuit (you can accomplish this by removing one battery terminal if you wish). Then your meter goes where you opened up the circuit (i.e.; if you removed one battery cable, then the meter will connect between that battery terminal and the cable that you removed from it).
Don't forget to set your meter to DC Amps and, most likely, you will have to move the red test lead to a different jack on the meter....to something that says something like "Amps"
If you don't get something when doing the above, maybe the fuse inside your multi-meter is open. Should be easy enough to replace.

Steve

Ok, I tried taking the positive cable off the battery and measuring across there. The meter will very briefly say an amp or two, then the numbers dance wildly for perhaps two seconds, and it settles down to about .1A. Doesn't matter if the panel is in full sun or in shade, same thing happens. I'm not sure how to interpret that. I do have it set for dc, not ac.

The controller 'sees' the battery condition and charges accordingly. I wonder if my Morningstar Sunguard SG-4 sees the meter in the circuit and thinks it's supposed to go into float mode?

The Fluke 115 should be able to measure dc current. The probes have to go from the A(amp) input to Com and the internal fuse must be intact. It's good for 10 amp and 20 amps for 30 seconds.

Most inexpensive clamp on current probes only measure AC current. You'll need a more expensive DC clamp on current probe.

But your Fluke should do it.

I take the amps between the controller and battery, not from the array side of the controller.

For under 10a, you can just put your multimeter pos and neg as part of either the pos or neg controller to battery wire and read the amps. You will want alligator clips on the meter leads because you only have two hands!

Some multimeters instructions don't want you to leave it on amps more than a few seconds, so with them you can't leave it hooked up as a gauge you can keep watching. For that you can go on ebay and see a zillion cheap little ammeters you can get that work ok too.