Epever MPPT controller shows lower PV amps than multimeter reading at terminals on controller

[NotSoOaky]

Hi everyone,

I have 2x 180W 20.9V/ 8.61A panels connected in series which feed an Epever tracer AN solar charge controller that feeds 2x 100Ah batteries.

Yesterday at about 3pm in Albania I got the following readings:

Reading 1 - At the panels (unplugged where they enter my vans roof and measured with multimeter): 45V @ 2.57A

Reading 2 - At the screw terminals where the cables enter the charge controller: 30.9V @ 2.5A

Reading 3 - On the charge controller LCD under the PV pages: 30V @ 1.0A

The difference in voltage across all three readings makes sense to me, reading 1 is technically an open circuit voltage which is why it is so high and then the others are close enough.

There difference in amps doesn't make sense to me, why is it 2.5A literally at the controller terminals and then in the controller screen it says 1.0A?

 

[wpns]

How are you measuring current? Could one be Isc and the other be Imp?

 

[NotSoOaky]

How are you measuring current? Could one be Isc and the other be Imp?

Could be! I imagine the controller measures Imp, our panels should be able to generate a max of 8.61A.

With my multimeter I am setting it to DC current on the 20A setting and placing the the black lead on the screw on the PV negative terminal and the red lead on the screw on the PV positive terminal on the SCC. I get a little spark when I do this. Not sure if this is Imp or Isc?

 

[NotSoOaky]

After googling it does seem like I was measuring Isc which would explain why my reading is higher than the SCC.

That said my batteries are at 12V so the system should be in Bulk charging mode so it should be pulling max amps, right?

 

[wpns]

If you are shorting the panels out with your DVM then you are measuring Isc

 

[wpns]

That said my batteries are at 12V so the system should be in Bulk charging mode so it should be pulling max amps, right?

No, it should be pulling max power (I assume MPPT), so Imp

 

[NotSoOaky]

No, it should be pulling max power (I assume MPPT), so Imp

Yep MPPT controller, there is something off with our system. We have some people next to us that are currently pulling way more power than we are. I have another post trying to confirm my understanding of the Epever controller so once I get an answer there I'll look further. Thank you!