Solar Charging Issue

HE

heinphoto

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Aug 28, 2019
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San Francisco Bay Area (East Bay)
I installed a Victron SmartShunt Battery monitor in the battery compartment of our 2020 Grandby earlier this morning. When I reconnected the batteries, everything looked good. The MPPT controller was charging the batteries in "Bulk" mode and looked normal.

I checked things after lunch, and the charging state is "Off". The solar voltage also looks low with the sun directly overhead (13.6 V). This is the factory Overland Solar 100/15 MPPT controller, which is a rebranded Victron BlueSolar controller. The green LED is blinking and the yellow LED is off. The Victron manual says this means that there is no power from the panel. However, I'm seeing voltage from the panel.



Any suggestions about what to troubleshoot next? Where is the fuse for the solar panel in newer campers? I don't think that is the problem, since I am seeing voltage, but I should probably check it.


MPPT 0V Off.jpg

Thanks,
-Scott
 
Is the 13.6V that the controller is reporting consistent with what you are measuring from the panels with your meter? If so, that is not enough for the MPPT to start charging and could indicate a problem with the panels.

Can you disconnect one of the solar wires from the charge controller (so it is not part of the circuit) and the measure the solar panel open circuit voltage and short circuit current? This will tell you if the panel is bad.

If that checks out, next thing to check is the controller. While you have the panel disconnected, also disconnect one of the battery leads to remove power from the controller for a few seconds (which will reset it). Reconnect the battery, then reconnect the panel and see what happens.
 
rando said:
Is the 13.6V that the controller is reporting consistent with what you are measuring from the panels with your meter? If so, that is not enough for the MPPT to start charging and could indicate a problem with the panels.

Can you disconnect one of the solar wires from the charge controller (so it is not part of the circuit) and the measure the solar panel open circuit voltage and short circuit current? This will tell you if the panel is bad.

If that checks out, next thing to check is the controller. While you have the panel disconnected, also disconnect one of the battery leads to remove power from the controller for a few seconds (which will reset it). Reconnect the battery, then reconnect the panel and see what happens.
Click to expand...
When I measure the voltage at the portable solar connector on the rear of the camper, I also measure ~13.6V. However, I'm not sure how that is connected to the panels and controller. The way that FWC mounted the charge controller makes it difficult to access the panel and battery wire connectionss, but I will have to give it a shot.

Thanks,
-Scott
 
You can disconnect the solar panel at the roof to check open circuit voltage and short circuit current.

Also, before you attempt to measure short circuit current make sure your meter can handle the rated short circuit current of the panel. You could blow a meter fuse or damage your meter. Mine, for example, will measure up to ten amps but is unfused for that highest setting. I have to be careful using it.
 
Hey Scott, since you made a change recently, that is a good place to start. Can you reverse your recent shunt installation?

Another possibility would be have to have been pre-existing, namely that your battery is charged, so the charger isn't charging. I'd have thought it would go into float mode, but am not super familiar with rebranded version of the MPPT.
 
Not an expert… but but I had a similar issue when setting mine up. Make sure the settings on the Mppt did not get changed on the battery voltage. If it thinks the bat is full it won’t charge or show any volts coming in from the solar and basically turn off.
Also, in the past are you sure your battery was getting charged by the solar panel and not just the truck? I wonder if possibly FWC did not hook the battery to the solar/mppt?
 
Status update... When I got up this morning the controller was still showing similar status as yesterday. So, I decided to go for a hike to clear my head before doing more troubleshooting. When I got back, I was getting ready to check the voltage at the panel and when I checked the controller status again - it looked normal!

So, I'm not sure what to think - it is certainly possible that I was paying more attention to the status/data after installing the shunt and found a problem that wasn't really there. I just don't remember the controller shutting off like that before. I did double check the controller settings - I had actually saved the settings using the App before I installed the shunt, and then restored them afterwards.

I have turned on the refrigerator and fans to give it a load and will see how it behaves today. Hopefully just a false alarm and not some sort of intermittent problem.

Thanks for everyone's comments - I'm obviously still on the steep part of the learning curve with these solar setups.

MPPT Status 7-4-2021-1.jpg
 
So, I think I figured out the cause, but don't know why its happening. When I started the truck just now the charge controller appeared to reset, the battery state went from "Float" to "Off", and the solar voltage dropped to 13.5 V. It stays that way even after I turn off the truck.
​
⁠When I hooked up the shunt, I didn't make any changes to the Blue Sea ACR connections. I just moved the negative leads from the Battery- post to the "System -" post on the shunt and the "Battery-" post on the shunt to the Battery- post with a single cable. I'm not sure how helpful this is but I have attached a photo of the battery box with the shunt installed.

Battery Compartment with Shunt-50x50%.jpg
 
Problem solved! After I initially set up the SmartShunt, I had enabled "VE Smart Networking" between the shunt and controller thinking that it would provide a more accurate battery voltage. When I started having problems, I was so focused on the panel that I forgot I had enabled that option. I just disabled Smart Networking and now the system is behaving normally when I start the truck. I'm guessing that starting the truck generated interference that interrupted or corrupted the data stream on the Bluetooth connection causing the controller to reset/shutdown. The SmartShunt has a very weak Bluetooth signal, so that probably contributed. This turned out to be an "interesting" troubleshooting exercise - thanks to everyone who commented and helped me think this through!
 
heinphoto said:
Problem solved! After I initially set up the SmartShunt, I had enabled "VE Smart Networking" between the shunt and controller thinking that it would provide a more accurate battery voltage. When I started having problems, I was so focused on the panel that I forgot I had enabled that option. I just disabled Smart Networking and now the system is behaving normally when I start the truck. I'm guessing that starting the truck generated interference that interrupted or corrupted the data stream on the Bluetooth connection causing the controller to reset/shutdown. The SmartShunt has a very weak Bluetooth signal, so that probably contributed. This turned out to be an "interesting" troubleshooting exercise - thanks to everyone who commented and helped me think this through!
Click to expand...
Nice catch on the disable switch, and good on you for sticking with it and sorting this out on your own. - Rich
 
Unfortunately, the saga continues... The system behaved normally for a few days after I disabled Smart Networking, so I thought I had it solved. But now it has stopped charging completely. The charge controller reports a panel voltage of 13-14V in full sun, which is too low to start charging, so the charging state is "Off" (and there has been no charging for several days despite the battery voltage dropping to 12.5V). However, when I measure the voltage at the panel on the roof it is 26V, which is in the "normal" range for this panel. My multimeter has a maximum current rating of 10A, so I decided not to measure the short circuit current at the panel. I tried resetting the controller again, but there was no change.

Fortunately, I had already scheduled a solar and wiring upgrade for late August and the installer (KP Pawley in Reno) was able to squeeze me in for the solar portion of the upgrade (charge controller and panel) before a trip we have coming up in mid-August. So, I should know more in a few weeks if KP is able to diagnose the problem. However, I wanted the "record" to show that "Smart Networking" was not the cause. I'm guessing it is the panel, but we will see...

-Scott
 
heinphoto said:
Unfortunately, the saga continues... The system behaved normally for a few days after I disabled Smart Networking, so I thought I had it solved. But now it has stopped charging completely. The charge controller reports a panel voltage of 13-14V in full sun, which is too low to start charging, so the charging state is "Off" (and there has been no charging for several days despite the battery voltage dropping to 12.5V). However, when I measure the voltage at the panel on the roof it is 26V, which is in the "normal" range for this panel. My multimeter has a maximum current rating of 10A, so I decided not to measure the short circuit current at the panel. I tried resetting the controller again, but there was no change.

Fortunately, I had already scheduled a solar and wiring upgrade for late August and the installer (KP Pawley in Reno) was able to squeeze me in for the solar portion of the upgrade (charge controller and panel) before a trip we have coming up in mid-August. So, I should know more in a few weeks if KP is able to diagnose the problem. However, I wanted the "record" to show that "Smart Networking" was not the cause. I'm guessing it is the panel, but we will see...

-Scott
Click to expand...
Any updates on the cause?
 
Yes, the solar panel failed. The installer had seen this behavior before with the Overland Solar panel where the panel voltage checks out fine under no load, but can't generate enough voltage to activate the controller under load. He ended up replacing the 160W panel with a 330W panel, changed out the rooftop SAE connector with an MC4, which he feels is more reliable, and upgraded to a Victron 100/30 mppt controller. I also had the truck wiring upgraded to 4 AWG and had a DCDC charger installed so that I can easily drop in a LiFePO4 battery when the current AGMs need to be replaced. I'm really pleased with the system. I don't have to worry/think much about power now.
 
rando said:
I hope they warranteed the solar panel! Unfortunately this seems to be another example of lower reliability from semi-flexible solar panels. It may be worth adding your experience to the thread on these failures: https://www.wanderthewest.com/forum/topic/10808-ultimate-flexible-solar-panels-successes-and-warranty-replacements/
Click to expand...
Since I had already planned to replace the 160W panel with a 300+ W panel, I didn't make a warranty claim. However, everything I have read is that Overland Solar has been very good about warranty and product support.
 
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