12v 80 watt solar panels not adding up!

[Solar Sign]

wondering if I have a problem with one of these panels or something is off. I check the voltage and amperage of each panel individually. There about the same. Each one showing around 2 amps. I wire 2) 80 watt 12v panels in parallel they come together just before the charge controller. After the Y I stab the insulation for a reading. It is only 2 amps. I was expecting 4 amps. Voltage is correct around 18-20volts.

I bought another multi meter just to make sure that wasn't the problem. A Klein Cl2000. It's reading the same.

I have wired 3 of these before in the sun and as I connected them I noticed an increase in amperage on each one. Not sure what's going on here, I already replaced one of them with another panel and same results.

Any ideas? Thank in advance.

[Solar Sign]

Any ideas what might be the problem here? The panels each have 3 diodes on them.

wondering if I have a problem with one of these panels or something is off. I check the voltage and amperage of each panel individually. There about the same. Each one showing around 2 amps. I wire 2) 80 watt 12v panels in parallel they come together just before the charge controller. After the Y I stab the insulation for a reading. It is only 2 amps. I was expecting 4 amps. Voltage is correct around 18-20volts.

I bought another multi meter just to make sure that wasn't the problem. A Klein Cl2000. It's reading the same.

I have wired 3 of these before in the sun and as I connected them I noticed an increase in amperage on each one. Not sure what's going on here, I already replaced one of them with another panel and same results.

Any ideas? Thank in advance.

[Raul]

If you are using a Y connector and not a common buss bar it may be that connector is not adding up . If each individual panel outputs 2a then 3 of them in paralel should add up .
I would test them with the wires from the panels directly into a block connector or common buss bar to eliminate that Y pice connector and take a proper reading instead stabbing the insulator.

[inetdog]

It is possible that the state of charge of your batteries is such that the Charge Controller (CC) only needs to draw 2A from the panels to get the current that the batteries will accept.
Try either letting your battery discharge further (but no below 50%) and test again or connect a load to the battery bank while charging as see if the CC output current and the panel current increase.

I am not sure how you are measuring current using an insulation piercing connection. Normally that will only let you measure voltage unless you are using the meter to short out the panels completely. When you put the two panels in parallel the voltage should not be expected to increase unless the CC is not using the full available power.

What type and rating of battery do you have and what is the make and model of your CC?

[PNjunction]

Inetdog hit upon one possible problem: your batteries are already nearly fully charged, and are in what's known as the "absorb" stage. Discharge and try again.

Other possible issue: You have made the connections in the wrong sequence for the controller. That is, one usually connects the batteries FIRST, and the panels LAST. If you do this backwards, many controllers assume you have a bad battery and will either refuse to work, or default to a very low current state no matter what. It is trying to protect what it THINKS is a bad battery (dead at zero volts!) by the fact that it is being connected last and may stay in a low-current limited state.

Ideally, and 80w panel should produce somewhere near 4.5A. (using the P/I*E formula: 80w/18v = 4.4A each) You have two, so under BEST conditions, and a somewhat discharged battery, you are talking about 8.8A total. Make sure your controller is at least 16-20A capable.

You may want to test the panels individually if you suspect something else is wrong:

1) Disconnect the panels from each other and the controller.
2) Put a towel over a single panel
3) Move the RED probe from your multimeter to the CURRENT measuring jack.
4) Now rotate the switch to dc current
5) Attach across panel leads
6) Remove towel.

In your haste to do this, don't forget that if you want to change your metering to volts, REMOVE THE MULTIMETER LEADS, move the red probe back to the voltage jack, rotate switch to dc voltage.

If you forget to move your probe from current to voltage when changing your measurements, then goodbye multimeter fuse normally.

[Solar Sign]

If you are using a Y connector and not a common buss bar it may be that connector is not adding up . If each individual panel outputs 2a then 3 of them in paralel should add up .
I would test them with the wires from the panels directly into a block connector or common buss bar to eliminate that Y pice connector and take a proper reading instead stabbing the insulator.

I got rid of the 2 to 1 "Y" and used a slice connector. Still the same reading.

It is possible that the state of charge of your batteries is such that the Charge Controller (CC) only needs to draw 2A from the panels to get the current that the batteries will accept.
Try either letting your battery discharge further (but no below 50%) and test again or connect a load to the battery bank while charging as see if the CC output current and the panel current increase.

I am not sure how you are measuring current using an insulation piercing connection. Normally that will only let you measure voltage unless you are using the meter to short out the panels completely. When you put the two panels in parallel the voltage should not be expected to increase unless the CC is not using the full available power.

What type and rating of battery do you have and what is the make and model of your CC?

75ah AGM Deep cycle, EP solar 20amp ls2024rp

Inetdog hit upon one possible problem: your batteries are already nearly fully charged, and are in what's known as the "absorb" stage. Discharge and try again.

Other possible issue: You have made the connections in the wrong sequence for the controller. That is, one usually connects the batteries FIRST, and the panels LAST. If you do this backwards, many controllers assume you have a bad battery and will either refuse to work, or default to a very low current state no matter what. It is trying to protect what it THINKS is a bad battery (dead at zero volts!) by the fact that it is being connected last and may stay in a low-current limited state.

Ideally, and 80w panel should produce somewhere near 4.5A. (using the P/I*E formula: 80w/18v = 4.4A each) You have two, so under BEST conditions, and a somewhat discharged battery, you are talking about 8.8A total. Make sure your controller is at least 16-20A capable.

You may want to test the panels individually if you suspect something else is wrong:

1) Disconnect the panels from each other and the controller.
2) Put a towel over a single panel
3) Move the RED probe from your multimeter to the CURRENT measuring jack.
4) Now rotate the switch to dc current
5) Attach across panel leads
6) Remove towel.

In your haste to do this, don't forget that if you want to change your metering to volts, REMOVE THE MULTIMETER LEADS, move the red probe back to the voltage jack, rotate switch to dc voltage.

If you forget to move your probe from current to voltage when changing your measurements, then goodbye multimeter fuse normally.

Yep this was the issue. The battery was fully charged and on a float charge. That's why when I connected the 3 panels before (with no battery on them) one at a time they all added up correctly.

Thank you all for the replies.