Charge controller shuts off every few minutes then comes back on

[SolarNoah]

I would dial down ChgLimtVol, EquChgVol, and BstChgVol all to just 14.0 volts. Your batteries seem to be very close to completely full, so this will likely result in low current until you start pulling some load and take some energy out of the batteries.

I tried this and no luck. This time the SCC crashed and didn't come back on. After 20 minutes, I popped the circuit breaker to break the connection with the batteries, reset it, and it started working again. I have attached the image of the battery monitor app and the screen on the SCC (both while the SCC was not providing power).

I shaded my panels a little bit and no more trouble for the day. They are hovering around at 14.1v, hopefully balancing. I may have already given them a chance to balance the other day. I was at full charge and the SCC was hovering around 0amp output.

Any other ideas?

Thanks,
Noah

 

[SolarNoah]

Do you know at what voltage the charge controller maxes out?

if the cells are nigh full, it would be easy for your panels to exceed 90V, especially if the weather is cool.

Just following up on this. Looks like it maxed out at around 75v. I attached a photo of the SCC screen above. Best, Noah

 

[HRTKD]

The MPPT is displaying a an input voltage that is exactly half what it is rated for. Coincidence?

Take one of your panels out of the equation by disconnecting it. Run with just one and let's see what happens. Given that you're running OK with a shaded panels lends credence to the thought that you have to much power going into the solar charge controller.

 

[SolarNoah]

The MPPT is displaying a an input voltage that is exactly half what it is rated for. Coincidence?

Take one of your panels out of the equation by disconnecting it. Run with just one and let's see what happens. Given that you're running OK with a shaded panels lends credence to the thought that you have to much power going into the solar charge controller.

I hear you- having the shaded panel makes me think that too much power is part of the issue. I just don't understand why this is or how to fix it. Do you think this is an issue with my setup or with the solar charge controller? The controller should be able to handle 1600W at 24v. I just don't get it...

When I run with just one panel, what would I be looking for? Does this just rule out any issues with the batteries?

Thanks and sorry for all of the questions.

 

[HRTKD]

A single panel should give you 75 / 2 volts, assuming that the two 300 watt panels you're using (from your first post in this thread) are wired in series.

If running with a single panel works, then I would assume that your solar charge controller is either misconfigured or has gone bad. I'm biased (I use Victron MPPT devices) but there seem to be a lot of strange issues with Renogy the past few weeks. Quality control? I don't know.

 

[mikefitz]

Hello! I have been having an issue with my charge controller that I have been unable to resolve. Any insight would be very much appreciated.

System (only what's relevant):

• Two, 300w 24v solar panels in series. 30 amp inline fuse before charge controller.
• 60 amp renogy rover MPPT charge controller that goes to a 40 amp fuse
• 12v lithium batteries
• *everything listed above is running on 10awg wire (using the same wire that came with the solar panels)
• smart battery monitor

Issue:

• Batteries charge like normal in the morning. Around mid-day (seems to be when I'm pulling 27+ amps), my charge controller goes into a strange cycle.
  • It charges the battery (usually gets around 90% charged), shuts off (the charge controller doesn't show any warning lights, it just shows that it isn't receiving any sun), then turns itself back on.
  • This cycle usually repeats every few minutes until either (1) the batteries are fully charged, or (2) I block the solar panels to reduce the incoming sunlight.
  • Photo attached showing a few minutes of this on the battery monitor app. Absolutely no power is coming in at the low points. My batteries are just draining. I just didn't have much running when I took this photo.

I have been on the phone with renogy all week and haven't had much luck. So far, I have:

• checked for loose wires
• checked for hot wires. The wires coming out of the charge controller and going to the battery were warm, but not hot.
• messed around with the settings on the charge controller
• reset the charge controller
• scoured the internet for any similar issues... but have come up empty!

I have had this system running well for a few months, but recently have moved to a place that gets more sun (I'm in a campervan). I assume this may have something to do with it.

The only things I can think of are:

• There is an issue with my charge controller. Renogy said this may be the case. I'm under warrantee, so can swap it out if needed.
• Something with the wiring? Maybe I need to be using a higher gauge? That said, I don't know why this would cause the controller to shut off like this. I know 10awg wire isn't ideal, but I called renogy when I set this up; they didn't seem to think the 10awg wire would be an issue...
• Something going on with one of my fuses?

Thanks for reading this far! Really hoping someone is able to shed some light on this.

Cheers,
Noah

My guess is internal thermal overload as already suggested, or a component overheating. Try fan cooling the controller to see if the problem goes away or alternatively heating it to see if this creates the issue.

Mike

 

[jtvt]

Some troubleshooting with a voltmeter and clamp on amp meter would help. Could be the equipment isn't even showing accurate values.

 

[SolarNoah]

A single panel should give you 75 / 2 volts, assuming that the two 300 watt panels you're using (from your first post in this thread) are wired in series.

If running with a single panel works, then I would assume that your solar charge controller is either misconfigured or has gone bad. I'm biased (I use Victron MPPT devices) but there seem to be a lot of strange issues with Renogy the past few weeks. Quality control? I don't know.

I just tried running a single panel-- no issues. Any reason I would need to test the other panel? If so, I'll likely need to wait until tomorrow because the sun is getting low. Sounds like it may be an issue with the charge controller after all. Other comments say maybe something is overheating in the controller. I think I've wired it up properly, so either way, it sounds like I'll need to tap into that warrantee.

 

[HRTKD]

Picture of how you have the solar charge controller installed?

 

[SolarNoah]

Picture of how you have the solar charge controller installed?

Apologies, it is in a tight space. That said, I think there is enough room for airflow and everything is cool to the touch.

• The solar panels are wired in series
• I have the positive solar lead going into the PV+ spot
• the negative solar lead going into the PV- spot
• The Positive battery line going from the controller to a 40amp fuse (which isn't popping when the issue happens) and then to the positive busbar
• The negative battery line going from the controller to the negative busbar.
• All solar-related wires are 10AWG stranded cable. The same wire that came with the solar panels

Please let me know if I can take any more specific photos (unfortunately they'll be close ups)

I appreciate you so much. Thank you.

 

[HRTKD]

Install looks OK to me.

 

[SolarNoah]

Install looks OK to me.

Awesome-- thank you so much. I'm going to test it one more time tomorrow to make sure I'm having no issues with one panel, and will then try to get a replacement charge controller. Might be a few weeks, but I'll update with the result!

 

[Roswell Bob]

With the panels or wires? Or too hard to tell?

The machine that keeps turning off and on. That is typically what you see. Gets hot, turns off, cools down, turns on. Fan spinning ok? I'm just throwing it out there. Probably nonsense, but if you haven't looked at it then take a peek. Make sure unit is well ventilated and fan spinning. If it starts doing it then blow some cold air on it and see if it stops or slows down. Blow (gently) some hot air on it and it should cycle faster.

 

[SolarNoah]

The machine that keeps turning off and on. That is typically what you see. Gets hot, turns off, cools down, turns on. Fan spinning ok? I'm just throwing it out there. Probably nonsense, but if you haven't looked at it then take a peek. Make sure unit is well ventilated and fan spinning. If it starts doing it then blow some cold air on it and see if it stops or slows down. Blow (gently) some hot air on it and it should cycle faster.

Ah- the machine causing me trouble. Makes a lot of sense

Thanks! I’ll check that out. So far all signs point to issues with the solar charge controller, so very good chance this could be it.

 

[GXMnow]

I tried this and no luck. This time the SCC crashed and didn't come back on. After 20 minutes, I popped the circuit breaker to break the connection with the batteries, reset it, and it started working again. I have attached the image of the battery monitor app and the screen on the SCC (both while the SCC was not providing power).

I shaded my panels a little bit and no more trouble for the day. They are hovering around at 14.1v, hopefully balancing. I may have already given them a chance to balance the other day. I was at full charge and the SCC was hovering around 0amp output.

Any other ideas?

Thanks,
Noah

Looking at your 2 images here, that looks like completion of charge with a full battery. The constant current charge at about 25 amps, pulled the battery to the full set voltage, then it shut down. I don't see it transition to constant voltage though, as it looks like the current fell fast. It actually went down to a little bit of load. The charge controller screen also shows the battery is at 100%. The voltage falling down to 13.3 is not too bad with the cut off at just 13.7 volts. It is normal for LFP to drop a bit when the current drops like that, and in this case it also started supplying some current out. That looks like a load of 5-6 amps on the battery monitor. I think your charge controller is just shutting off due to it sensing a full battery. Pull some load on the system and see what it does. Once the voltage comes down a bit, the charge controller should kick back on. If the solar is supplying more power than you are using, it may shut off again.

 

[SolarNoah]

Looking at your 2 images here, that looks like completion of charge with a full battery. The constant current charge at about 25 amps, pulled the battery to the full set voltage, then it shut down. I don't see it transition to constant voltage though, as it looks like the current fell fast. It actually went down to a little bit of load. The charge controller screen also shows the battery is at 100%. The voltage falling down to 13.3 is not too bad with the cut off at just 13.7 volts. It is normal for LFP to drop a bit when the current drops like that, and in this case it also started supplying some current out. That looks like a load of 5-6 amps on the battery monitor. I think your charge controller is just shutting off due to it sensing a full battery. Pull some load on the system and see what it does. Once the voltage comes down a bit, the charge controller should kick back on. If the solar is supplying more power than you are using, it may shut off again.

This also could be the case...

Ok. One more test today to see if I have a faulty solar charge controller or if the batteries are just full. As soon as I'm seeing the SCC start cycling, I'll drain my batteries significantly (run the water heater or something) to see if it kicks back on and stays that way.

The reason I think it may be an issue with the charge controller is like you say, no transition to to a constant voltage. In the past or if I'm getting slightly less sun than I've recently been getting, the SCC would never shut off. The PV indicator light would stay on, but just limit the power going to the batteries to match what I'm pulling out of them.

Thanks for all of your help and suggestions. Very helpful!

Best,
Noah

 

[SolarNoah]

Shutoff at 13.15v. Battery at 75.9%. Calling Renogy to get a replacement unit today. Thanks for everyone's help!

 

[HRTKD]

An additional test to run is to put a load on the system that exceeds the number of watts the solar charge controller is putting into the system. This should be a way to keep the battery from reaching 100%. If the shutoff is indeed due to the solar charge controller thinking the battery is fully charged, then in this test that shouldn't happen.

 

[SolarNoah]

An additional test to run is to put a load on the system that exceeds the number of watts the solar charge controller is putting into the system. This should be a way to keep the battery from reaching 100%. If the shutoff is indeed due to the solar charge controller thinking the battery is fully charged, then in this test that shouldn't happen.

Just got the charge controller running again and tried this test. I think whatever is happening is getting worse...

I tried draining the battery for a few minutes and the SCC didn't shut off. Maybe just a coincidence (weaker sun or something). I let it charge back up a little bit (still nowhere near fully charged) and the SCC disconnected again. It is taking longer and longer to flip back on.

I got it going again, this time with the solar panels shaded. The fact that it is continuing to charge shaded, makes me think that it is an issue with the heat. Or the SCC can't handle a certain amount of volts (shutting off at 75v again).

 

[ghostwriter66]

An additional test to run is to put a load on the system that exceeds the number of watts the solar charge controller is putting into the system. This should be a way to keep the battery from reaching 100%. If the shutoff is indeed due to the solar charge controller thinking the battery is fully charged, then in this test that shouldn't happen.

Good job/advice/trouble shooting HRTKD ...

I'm always that mean person that starts off with "You do have a DVM and an amp meter - correct?" ... if not - trouble shooting just really becomes a whack-a-mole guessing game ... LOL