Multimeter Mystery, Solar Troubleshooting

[sgtPluck]

I'm wondering if someone can explain what I'm seeing with my multimeter.

I have two multimeters, one standard and one clamp meter.

I'm trying to trouble shoot problems with my solar setup and the meters are giving me readings I don't understand.

My solar controller (Solar Boost 2512ix) is not showing any LEDs after I installed 2 new panels. So I am trouble shooting.

Both meters show me 20v coming into the + – at the solar controller. So that's good (I have three panels in parallel setup)

Then for current, first I tried with the clamp meter and it showed 0 amps coming through the positive wire.

Then I set up the regular multimeter in series on the positive wire, and it showed me 4.49 amps. I put the clamp meter on the positive meter wire to verify that the clamp meter is working....



It is.

My question is what does this tell me?
Does the clamp meter showing 0 amps through the solar controller when that is wired up suggest the controller is not drawing any current/is broken.

If that's the case where does that 4.49 Amps come from/go to when the multimeter is connected, is the multimeter itself drawing that ??

I'm confused

Thanks

[Opie91]

A few questions:

What is your voltage at the output side of the controller?

Do you have some type of current protection on the output side of the controller that is now too small for the increased output?

It is highly unlikely that the multi-meter is drawing the amperage. Please explain exactly how you hooked up the meter to obtain this reading. Output side of controller, positive side of output? Be specific as possible.

Good luck

[Jim Cate]

Assumption: that you have the VOM in series between the output of the controller and the battery bank.

if this is correct, then I'd suspect that the clamp meter is defective. The 4+ amps shown by the VOM must be going into the battery, and sounds like a reasonable value for a small solar array in good sunlight or a larger one in less good light.

Jim

[noelex 77]

A clamp on multimeter will read 0 if you clamp it over both the negative and positive wires. I suspect this may be be the problem given your conventional multimeter and your clamp on multimeter is reading 4A+ in the photo with just the positive wire used.

For the clamp on multimeter to work just the positive, or negative wire needs to pass through the jaws. Not both. If both wires are used the net current is zero.

I know in your post you said that you measured the positive wire, but my best guess as to the cause of your unusual readings was that the negative wire was also included within the jaws of the clamp on multimeter. It is an easy mistake to make.

[Jim Cate]

Originally Posted by noelex 77

A clamp on multimeter will read 0 if you clamp it over both the negative and positive wires. I suspect this may be be the problem given your conventional multimeter and your clamp on multimeter is reading 4A+ in the photo with just the positive wire used.

For the clamp on multimeter to work just the positive, or negative wire needs to pass through the jaws. Not both. If both wires are used the net current is zero.

I know in your post you said that you measured the positive wire, but my best guess as to the cause of your unusual readings was that the negative wire was also included within the jaws of the clamp on multimeter. It is an easy mistake to make.

Nolex, I considered that too, but the photo shows the clamp around only the red wire.

Jim

[smac999]

Is your clamp meter in AC amps?

[zboss]

Some multimeters have different internal fuses for different functions. Check to make sure both fuses are OK.

[pesarsten]

I suspect that you do not have your clamp on amp meter set for DC amps, set it to 20 amp scale and I think you have to push the blue button for DC. Check the manual.

[Viking Sailor]

Pardon me - but when I look at the two meters I see the hardwired one display showing the number 4.49 and the clamp on meter display showing the number 4.43. I have no idea what the parameters and ranges these meters are set to display. However, these displayed values seem close enough to be displaying the same thing.

[Jim Cate]

Originally Posted by Viking Sailor

Pardon me - but when I look at the two meters I see the hardwired one display showing the number 4.49 and the clamp on meter display showing the number 4.43. I have no idea what the parameters and ranges these meters are set to display. However, these displayed values seem close enough to be displaying the same thing.

Crikeys, you're right!! I hadn't looked closely at the photo and was going on the posted info. Your observation is spot on, and the meters agree within reasonable error.

Jim

[Neptune's Gear]

The Uni-T meter does not have a setting for AC or DC amps - it auto senses. They are a great meter, and likely to be more accurate than the yellow one( unless its a Fluke?) I suspect the issue was that when it was used directly on the solar cables, rather than the other MM cable as shown, it was around both cables?

[svlamorocha]

Originally Posted by Neptune's Gear

The Uni-T meter does not have a setting for AC or DC amps - it auto senses. They are a great meter, and likely to be more accurate than the yellow one( unless its a Fluke?) I suspect the issue was that when it was used directly on the solar cables, rather than the other MM cable as shown, it was around both cables?

The manual I have for that meter says that you have to choose between AC and DC for clamp current measurements

Sent from my SM-G9287 using Cruisers Sailing Forum mobile app

[noelex 77]

Originally Posted by Jim Cate

Crikeys, you're right!! I hadn't looked closely at the photo and was going on the posted info. Your observation is spot on, and the meters agree within reasonable error.

Jim

Yes the photo shows the clamp on meter working correctly when attached to the multimeter wire. The mystery is why it reads zero when attached arround the solar panel "+" wire.

My guess is that the solar panel wire is not a + but both + and - conductor bundled together in which case zero current is the right answer for a clamp on meter. It is easy to ignore the negative wire especially when it's referred to as "ground" but it conducts the same current as the positive wire.

[facciatosta]

Originally Posted by sgtPluck

I'm wondering if someone can explain what I'm seeing with my multimeter.


Thanks

Conditions changed while you were manipulating your meters which took probably 2-3 minutes.
Controller changed its mind and decided to draw/output current(you probably had to disconnect input /output to get your VOM connected and inadvertently reset it) or clamp meter was not set up correctly or some other connections were not good. Put things back together and try again.

[smac999]

Originally Posted by noelex 77

Yes the photo shows the clamp on meter working correctly when attached to the multimeter wire. The mystery is why it reads zero when attached arround the solar panel "+" wire.

My guess is that the solar panel wire is not a + but both + and - conductor bundled together in which case zero current is the right answer for a clamp on meter. It is easy to ignore the negative wire especially when it's referred to as "ground" but it conducts the same current as the positive wire.

well does it have one wire or 2 coming off the panel?... if there is only one wire then they are together. every panel I've seen has 2. with mc4 connectors.