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roamer105 asked

Smart Solar 150/70 producing persistent error 38

Smart Solar 150/70 2+ years old fed by 3x HIT225Watt panels (675W total) connected in parallel with an OCV of about 50 Volts. The unit is connected to a system with a CCGX, BMV-712 Smart and a 3KW/120V Multi. Fed by a 900AH LiFePO4 battery. All of it installed in an RV.

All components are up-to-date in firmware.

5 days ago while the RV was parked inside an enclosed garage and the Multi plugged into shore power, the Smart Solar started to produce error #38 shutdown. When I took the RV on a trip, these errors continued to get logged and of course the Smart Solar was shut down. I read the instructions as to how to reset but I could not easily disconnect the panels. Nothing seemed to work. I downloaded the same (latest) firmware and then force-reloaded that firmware via load-file option. That succeeded and the unit started to work OK again for the rest of the day charging the battery.

I don't believe the problem is solved because I never got to the level of charge current that would be customary on a discharged lithium battery with full mid-day clear sunshine. The panels should have been able to feed at close to 600 Watts (per prior experience) but they were stuck at a max of 420 Watts and occasionally (maybe two to three times within 30 minutes for maybe 1 minute) the input (solar panel) voltage would fluctuate wildly quickly swinging from about 43V to 16V and levels between those values. Over the 2+ years this system is operational I have never seen this kind of behavior with a totally clear sky (no clouds and no obstructions) in the middle of the day.

Am I looking at a faulty Smart Solar unit? I will check the wiring and connectors from the panels to the unit when I get back from this trip. But I seriously doubt that there is a problem that would cause this type of behavior.

smart solar charging behaviour
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5 Answers
kevgermany avatar image
kevgermany answered ·

This link may help https://www.victronenergy.com/live/mppt-error-codes

As it is sort of working, check to see if the battery/charge settings in the MPPT are still correct, you might have lost them with a forced update.

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snoobler avatar image
snoobler answered ·

We're still close to equinox, so depending on your latitude, flat panels on an RV roof aren't going to perform great even without any partial shading from roof protrusions. 420W on 600W for this time of year actually sounds pretty good.

If you're in absorption mode, you're voltage limited, so hitting the system with a > 600W load will force the MPPT to output as much as the PV can deliver.

The voltage behavior you describe sounds like an MPPT sweep.

If your LFP batteries hit OVP and the MP charger briefly spiked as a result, that could have triggered the #38.

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roamer105 avatar image
roamer105 answered ·

"If your LFP batteries hit OVP and the MP charger briefly spiked as a result, that could have triggered the #38 "

Looking through the VRM logs I think that must have been the reason. The power failure (while plugged into shore with fully charged battery at float) lasts only 20 seconds because I have an automatic backup power generator. So the Multi restarted bulk after a short glitch with power back. I noticed a short voltage spike from the multi reaching just over 15V. The Smart Solar was powered and triggered the failure right at that point.

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roamer105 avatar image
roamer105 answered ·

My method of recovery from this HARD fault condition by re-installing the firmware may be a solution for anyone running into this if there is no easy way to disconnect the solar panels.

Suggestion for the developers: It would be nice to have a true "restart button" for this device on the Victron Connect (bluetooth) screen.

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roamer105 avatar image
roamer105 answered ·

I found the reason for the panel voltage fluctuations. The down-feed positive MC4 connector wire crimp was bad and over the course of years it corroded badly and actually got so hot that it burnt the wire insulation. When I unscrewed the stress retainer the wire practically fell out. I am sure fixing all of the panel wiring will take care of what I thought to be a charge controller issue combined with poor panel performance.

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