Breaker doesn’t trip but stops passing amps

Nepenthe · May 2022

Hey folks… Having an issue and looking for some ideas. I have a 12v 540w array that seems to effect my breaker once daily. The breaker won’t trip. It continues to register voltage but will stop passing amps. I trip it and reset it and everything is back to normal for the day.

The problem started when I added an additional panel (same specs) to the array. At first I thought it was the breaker. Replaced it and still having the same problem. I’ve looked over my wiring and don’t see any issues. Power is going into a Renogy MPPT controller. One thought is the controller is going bad, but that seems like a long shot.

Any thoughts???

BB. · May 2022

Welcome to the forum Nepenthe,

Assuming a good breaker... It does sound like a controller issue.

0. Check all wiring from solar array to controller to battery bank and make sure all connections are clean(no signs of corrosion)/tight/not overheated (browning/blackening of wire and insulation). Sometimes poor connections can start to heat up and temporarily "fix" themselves (or make things worse). And water can follow the wiring/enter the "weather entery point" from the array and flow/migrate down into electrical connections and cause rust/corrosion.

1. Measure the voltage across the Controller's Vpanel input terminals (if breaker tripped, terminals should read somewhere around zero to Vbatt volts).

2. Measure Vbatt output of controller (should be Vbatt + maybe a few 1/10ths of a volt if charging current flowing). You should see around 10.5 volts (battery dead) to 12.8 volts or so (battery charged/rested) to 14.4 to 14.8 volts (battery charging).

2. Turn off Array breaker, turn off controller's output/battery breaker. Wait 1 minute. Turn on Battery Breaker. Wait 10 seconds (until controller "boots")., then turn on array breaker (hard reset to controller).

What is your solar array configuration (Vmp, Imp, how many panels in series and parallel connections). For MPPT controllers, you want around Vmp-array=36 volts or so for optimum operation. You can go upwards of 65 Volts Vmp.

In cold conditions (typically sub freezing), Voc-array with 3 or more panels in series can exceed the Vpanel max input of the controller (typically 100 VDC max input for these type of controllers).

-Bill

Photowhit · May 2022

Welcome!

I believe you are resetting your charge controller.

You don't say where this breaker is, between the array and the charge controller or between the charge controller and the battery bank?

If you give the info Bill has asked for, we might be able to establish what is going on here. Sounds like you charge controller is shutting down because something 'out of bounds' is being introduced to the charge controller....

...or it might be simply that you have reached a fully charged state and the charge controller isn't semding any current to the battery bank! To test this you could introduce a load and the charge controller should allow more current to pass to handle the load.

Basics of battery charging;

The voltage you are seeing is the system voltage and not the battery voltage. If you are connected to charging or a load it will effect the system voltage.

During charging, there are basically 3 stages of charging, Bulk, Absorb, and Float.

BULK;

First thing when charging starts you will be in bulk, the voltage rises from what ever the system voltage was to a set point, around 14.5 volts. At that point the Charge controller stops the voltage from rising. Higher voltage can damage sealed batteries.

ABSORB;

Once the battery hits the preset point the charge controller keeps it at that point. Your batteries are roughly 80% full. Flooded batteries will start accepting less current at 80-85% full AGM/Sealed may go a little longer before accepting less current.

On many controllers you can set this point, Some will have different presets for Flooded, and sealed batteries, or flooded, AGM, and sealed batteries.

The charge controller has a couple ways to know when to switch to float, Most inexpensive Charge controller are just timed for 1.5-2 hours. Some will also see less current flowing through the charge controller and shut it down when minimal current is flowing through the controller. On more expensive charge controller. You can set battery capacity to give the Controller a better idea of when to stop. you can also set a longer Absorb time. Or set 'end amps' a amount of amps flowing through the charge controller to stop Absorb and switch to the final stage.

FLOAT;

Once the Controller has determined the battery is fully charged it reduces the voltage to a point where very little current is flowing to the battery. This will prevent the battery from over charging and heating up.

While in 'Float' the charge controller watch for voltage drop, which would indicate a load. If the voltage begins to drop the charge controller will allow as much current to flow from the panels/array to compensate and maintain the voltage. If the voltage can be maintained, the load will in essence be running directly off the array/solar. If the voltage drops below the preset float voltage, the controller may start a whole new cycle if it stays there for a period of time.

The system voltage drop you see at night when the sun goes down is the charge controller moving into a resting mode with no energy to contribute to the system.

The morning voltage may reflect a load present that is effecting the voltage level. With sealed batteries, you would want to disconnect the battery from the system and allow it to 'rest' for a while to get an accurate idea of it's SOC (State Of Charge) from the voltage.

Nepenthe · May 2022

BB. said:

Welcome to the forum Nepenthe,

Assuming a good breaker... It does sound like a controller issue.

0. Check all wiring from solar array to controller to battery bank and make sure all connections are clean(no signs of corrosion)/tight/not overheated (browning/blackening of wire and insulation). Sometimes poor connections can start to heat up and temporarily "fix" themselves (or make things worse). And water can follow the wiring/enter the "weather entery point" from the array and flow/migrate down into electrical connections and cause rust/corrosion.

1. Measure the voltage across the Controller's Vpanel input terminals (if breaker tripped, terminals should read somewhere around zero to Vbatt volts).

2. Measure Vbatt output of controller (should be Vbatt + maybe a few 1/10ths of a volt if charging current flowing). You should see around 10.5 volts (battery dead) to 12.8 volts or so (battery charged/rested) to 14.4 to 14.8 volts (battery charging).

2. Turn off Array breaker, turn off controller's output/battery breaker. Wait 1 minute. Turn on Battery Breaker. Wait 10 seconds (until controller "boots")., then turn on array breaker (hard reset to controller).

What is your solar array configuration (Vmp, Imp, how many panels in series and parallel connections). For MPPT controllers, you want around Vmp-array=36 volts or so for optimum operation. You can go upwards of 65 Volts Vmp.

In cold conditions (typically sub freezing), Voc-array with 3 or more panels in series can exceed the Vpanel max input of the controller (typically 100 VDC max input for these type of controllers).

-Bill

Thanks Bill! Great Info Here... The wires are all fine. I’ll wait for it to do it’s thing and get some measurements in the morning. I’m curious if it’s actually the controller.

Nepenthe · May 2022

Photowhit said:

Welcome!

I believe you are resetting your charge controller.

You don't say where this breaker is, between the array and the charge controller or between the charge controller and the battery bank?

If you give the info Bill has asked for, we might be able to establish what is going on here. Sounds like you charge controller is shutting down because something 'out of bounds' is being introduced to the charge controller....

...or it might be simply that you have reached a fully charged state and the charge controller isn't semding any current to the battery bank! To test this you could introduce a load and the charge controller should allow more current to pass to handle the load.

Basics of battery charging;

The voltage you are seeing is the system voltage and not the battery voltage. If you are connected to charging or a load it will effect the system voltage.

During charging, there are basically 3 stages of charging, Bulk, Absorb, and Float.

BULK;
First thing when charging starts you will be in bulk, the voltage rises from what ever the system voltage was to a set point, around 14.5 volts. At that point the Charge controller stops the voltage from rising. Higher voltage can damage sealed batteries.

ABSORB;
Once the battery hits the preset point the charge controller keeps it at that point. Your batteries are roughly 80% full. Flooded batteries will start accepting less current at 80-85% full AGM/Sealed may go a little longer before accepting less current.

On many controllers you can set this point, Some will have different presets for Flooded, and sealed batteries, or flooded, AGM, and sealed batteries.

The charge controller has a couple ways to know when to switch to float, Most inexpensive Charge controller are just timed for 1.5-2 hours. Some will also see less current flowing through the charge controller and shut it down when minimal current is flowing through the controller. On more expensive charge controller. You can set battery capacity to give the Controller a better idea of when to stop. you can also set a longer Absorb time. Or set 'end amps' a amount of amps flowing through the charge controller to stop Absorb and switch to the final stage.

FLOAT;
Once the Controller has determined the battery is fully charged it reduces the voltage to a point where very little current is flowing to the battery. This will prevent the battery from over charging and heating up.

While in 'Float' the charge controller watch for voltage drop, which would indicate a load. If the voltage begins to drop the charge controller will allow as much current to flow from the panels/array to compensate and maintain the voltage. If the voltage can be maintained, the load will in essence be running directly off the array/solar. If the voltage drops below the preset float voltage, the controller may start a whole new cycle if it stays there for a period of time.

The system voltage drop you see at night when the sun goes down is the charge controller moving into a resting mode with no energy to contribute to the system.

The morning voltage may reflect a load present that is effecting the voltage level. With sealed batteries, you would want to disconnect the battery from the system and allow it to 'rest' for a while to get an accurate idea of it's SOC (State Of Charge) from the voltage.

Thank you Photowhit… It may be that the controller is shutting off the array input, but it’s certainly not in a float state. It usually happens sometime at night. I have 2 arrays and 2 CCs. When I check on it in the morning the CC shows voltage coming in but 0 amps. When I pop the breaker and reset it full amps are back. It could be that it’s resetting the input but the CC is still connected to the batteries so I don’t feel it’s resetting the CC.

Photowhit · May 2022

Nepenthe said:
Thank you Photowhit… It may be that the controller is shutting off the array input, but it’s certainly not in a float state. It usually happens sometime at night. I have 2 arrays and 2 CCs. When I check on it in the morning the CC shows voltage coming in but 0 amps. When I pop the breaker and reset it full amps are back. It could be that it’s resetting the input but the CC is still connected to the batteries so I don’t feel it’s resetting the CC.

I hate getting info little by little....

So how early in the morning, and what does 'full amps' mean?

Solar panels will make voltage inside under a light. They may not even have enough power to run your controller. Hence no current flowing. Still don't know where the breaker is...

With 2 arrays and controllers, you could have other issues at times.

RCinFLA · May 2022

A breaker will stop the current flow. For breaker on a PV, the panels side will go to Voc and controller side may still show battery voltage.

Since it began after adding panels, you may be exceeding maximum PV input voltage level on controller.

When panel Voc is too high, many SCC will not start up to protect themselves.

Early cold mornings are usually the worst time. Panels are cold with their highest Voc. Once sun rises high enough the panels get warmed up from sun heating and Voc drops to a level acceptable to allow SCC to startup.

Breaker doesn’t trip but stops passing amps

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