Panels wired in Parallel but Amps not adding up

[Hank45]

I've installed the following PV/solar system on and in a shed: Four RS-M100 Rich Solar Panels, roof-mounted; Jarxioke 4000 Watt Pure Sine Wave Inverter; Two Eco-Worthy LiFePO4 12.8V 100Ah; 60A MPPT OEM Solar Charge Controller.
Solar panels are 100W, 18.6V (Vmp), 5.38A (Imp). I originally wired the panels in Series, and outputs were as expected: Volts up to about 80, Amps were appropriate. I rewired the panels in Parallel to see the difference. In Parallel, Volts are as expected, about 18. However, Amps are not adding up, but remain as if the panels are wired in Series. I measured the Amps directly from the panels before any current etc. reached the Charge Controller, and the Amps remain as if from a single panel, not additive of all four panels. I used 10 AWG copper wire to wire the panels.
My question: what are the possible reasons that the AWG is not additive? And thanks for any help.

 

[Supervstech]

I've installed the following PV/solar system on and in a shed: Four RS-M100 Rich Solar Panels, roof-mounted; Jarxioke 4000 Watt Pure Sine Wave Inverter; Two Eco-Worthy LiFePO4 12.8V 100Ah; 60A MPPT OEM Solar Charge Controller.
Solar panels are 100W, 18.6V (Vmp), 5.38A (Imp). I originally wired the panels in Series, and outputs were as expected: Volts up to about 80, Amps were appropriate. I rewired the panels in Parallel to see the difference. In Parallel, Volts are as expected, about 18. However, Amps are not adding up, but remain as if the panels are wired in Series. I measured the Amps directly from the panels before any current etc. reached the Charge Controller, and the Amps remain as if from a single panel, not additive of all four panels. I used 10 AWG copper wire to wire the panels.
My question: what are the possible reasons that the AWG is not additive? And thanks for any help.

How full is the battery?

 

[Ampster]

How full is the battery?

Yes, that is the critical question. We don't know the timing of each test either, The system may only be pulling from the panels what the loads of the house and the batteries need for charging. That may have changed between the two configurations. Without that data one can only assume.

 

[AT1(AW)]

Are you reading the Amps off of the charge controller? If so that is amperage going into the battery and would remain about the whether your panels are in series or parallel.

 

[Hank45]

Thanks for the replies. The Amp readings are before the charge controller - I disconnected the wires from the charge controller and read the Amps directly from the panels. I then reconnected the wires to the charge controller and read the Amps from the charge controller (which is connected to full batteries), same readings.

 

[Ampster]

The Amp readings are before the charge controller -

That does not inform the discussion because the charge controller is only going to pull the Amps that the loads including battery charging tell it to pull. If the loads were different at different times then the Amps will be different at different times. The Amps will be different at different places where the voltage is different. In other words the panel voltage will be different from the output voltage which most likely will be the charging voltage. The key is to measure the loads at the same place during the two different times to get a sense for what is going on in the system.

 

[Rednecktek]

(which is connected to full batteries)

Gotta throw a real load on and see what it does. With full batteries you're only going to get what's needed to maintain.

Also, how are you testing amps at the controller? Short and amp clamp or some sort of meter?

 

[Ampster]

Short and amp clamp

Yes, shorting the strings would give you a current reading that is more acurate. The trick is doing that in a way that you do not damage the MC4 connectors by connecting them or disconnecting them under the load of a short circuit.

 

[Rednecktek]

With 4 in parallel that's about 22a you should be seeing.

 

[Hank45]

Testing was with a multimeter. I've also used a full load in minimal sunlight, to see if the Amps would go up - no change. What I'll do tomorrow, during peak sunshine, is throw a full load, and then observe the Amps

 

[Rednecktek]

So you shorted the leads at the SCC and used an amp clamp or did the pass through amperage setting?

Unless you have a really REALLY nice meter, 20a is going to trip the meter and probably get the wires melty hot real quick if you do the pass through method. Even my high end Fluke tops out at 10a doing that, and the wires get toasty warm right quick.

You also need to test it under as optimum conditions as possible. If you're doing a load test when it's cloudy or darker the panels just can't physically provide much.

 

[Ampster]

Unless you have a really REALLY nice meter, 20a

A nice meter would be one with a clamp which can measure DC amperage greater than 20 Amps. They are more expensive than the traditional Clamp meters, many of which only measure AC Amps through the clamp.

 

[Rednecktek]

Yeah, Amazon Basics has one that was about $30 a couple years ago that did DC amp clamp and all the other features of my $80 Klien or a $600 Fluke that needed new leads out of the box.