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Michael Timler avatar image
Michael Timler asked

Victron Smart Solar 150/35 charging shutoff malfunction

Here is the configuration:
Two SmartSolar 150/35 loading a 48 V LiFePO4 Battery disconnecting without error at around 30A load. New system running two 150/35 on two identic pv strings. The webpage https://www.victronenergy.com/live/ba... is known to me.

Nevertheless, I have no DX-device installed and the chargers have no bus connection with the BMS of the battery.

All three Victron MPPTs I have installed are charging bulk until a voltage level of 52.3V until Absorption and 51.00V Float.
This results in: At 97% battery charge status, both of the 150/35 are into Absorption and end up at 99% in Float mode. On lower currents than about 30A, everything works fine..

Again, I stress: The Victron chargers do not "know" anything from the battery. No bus connection beetween Victron chargers and battery BMS at all. I know, that Victron recommends using a DX-device in combination with Pylontech batteries, however, the Solar MPPTs of Victron are universal chargers, that are described in the manual as for universal use. Therefore I claim that these controllers in the present configuration should basically work, even without BMS bus control.

The controllers are intentionally undersized regarding battery charging current. The manual and the Victron layout software say, that this is possible in my configuration and the particular chargers will limit charging currents higher than 35A each. I've already checked that and it works without any overtemparature problem for a while.

Here is the error description: Both controllers sometimes switch off at battery charging currents above 30A, regardless of the battery's state of charge, and independently from each other. At the same time there is no error message. Not in the csv sheet, the LED still shows blue, as if the bulk load would run normally. After about 20 minutes, the charge current is switched on again and the controller charges the battery normally. If the charge current of 30A and above continues, the cycle repeats after about 15 minutes.

For demonstration, I have uploaded a video to https://youtu.be/XXRgIShPb9g

I have never watched such a behaviour on these usually very reliable devices and hope, that someone can point me in the right direction.

Thank you very much!

smart solar set-up helpmppt charging
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7 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Michael Timler

Can you show the PV voltage / current while this is happening?


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Michael Timler avatar image Michael Timler commented ·

Here is another video with all four parameters visible:
https://www.youtube.com/watch?v=cSksnORrto4

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Michael Timler avatar image Michael Timler commented ·

Thank you very much for your reaction, Daniel.

Not yet, or is there a possibility to show all four meters (bat.current, bat.voltage, pv.current, pv.voltage in one screen of the app? Haven't found any possibility myself.

But there was no specific overvoltage problem visible to me, if that is your concern. The maximum Short-circuit voltage of the string is 140V, during the charging process it's around 100V.

What I have watched in detail is, that the shutdown always happens during a period, where the MPP is "readjusted". If I watch the bat.current and bat.voltage over longer periods, I have the impression, that the device starts a MPPT-process in regular distances of some minutes, which makes absolute sense to readjust the optimal MPP. And all shutdowns happen during one of these processes. If you watch the video, you can clearly see, that there is a MPP-process going on, before the shutdown happens.

My feeling (that can be wrong) tells me the following story: My chargers do a MPPT-process in situations of charging current of about 30A, which is about 80% of max current. The result of this process is an uncontrolled shutdown. The controller of the charger itself stays in the bulk loading modus and doesn't know anything from a shutdown. After some minutes, when another regular mppt-routine starts, the charger returns to charging "as normal" in the new tracked MPP.

This happens from time to time as soon as the current stays at about 30A. Unfortunately, at the beginning of reaching high currents, the chargers actually load at 35A for a while, and they actually limit the maximum current to 35A, as expected. Therefore I believe, that there is probably a temperature coefficient, which triggers the missbehaviour finally.

Sorry for the long story, but in my opinion this actually could be a software thing. On the other hand, if this where true, you, resp. Victron, would have had a lot of feed back and I would not be the only one to report this.

As soon as the weather is getting better over here, I will log the PV data for you.

Thank you for your interest and help!

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Michael Timler avatar image
Michael Timler answered ·

Thank you very much for your reaction, Daniel.

Not yet, or is there a possibility to show all four meters (bat.current, bat.voltage, pv.current, pv.voltage) in one screen of the app. Haven't found any possibility myself.

But there was no specific overvoltage problem visible to me, if that is your concern. The maximum Short-circuit voltage of the string is 140V.

What I have watched in detail is, that the shutdown always happens during a period, where the MPP is "re-adjusted". If I watch the bat.current and bat.voltage over longer periods, I have the impression, that the device starts a MPPT-process in regular distances of some minutes, which makes absolute sense to re-adjust the optimal MPP. And all shutdowns happen during one of these processes. If you watch the viceo, you can clearly see, that there is a MPP-process, before the shutdown happens.

My feeling (that can be wrong) tells me the following story: My chargers do a MPPT-process in situations of charging current of about 30A, which is about 80% of max current. The result of this process is an uncontrolled shutdown. The controller of the charger itself stays in the bulk loading modus and doesn't know anything from a shutdown. After some minutes, the MPPT-routine starts again, the charger starts its starting routine and proceeds charging "as normal".

This happenes from time to time as soon as the current stays at about 30A. Unfortunately, at the beginning of reaching high currents, the chargers actually load at 35A for a while, and they actually limit the maximum current to 35A, as expected. Therrfore I assume, that there is probably a temperature coefficient, which triggers the missbehaviour finally.

Sorry for the long story, but in my opinion this actually could be a software thing. On the other hand, if this where true, you, resp. Victron, would have had a lot of complaints and I would not be the only one to report this.

As soon as the weather is getting better over here, I will log the PV data for you.

Thank you for your interest and help!

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Michael Timler avatar image
Michael Timler answered ·

Here is another video with all four parameters visible:
https://www.youtube.com/watch?v=cSksnORrto4

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Hi @Michael Timler

did you have a chance try the older firmware versions I sent you?

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spark88 avatar image
spark88 answered ·

Just as an FYI that I have added my details to https://community.victronenergy.com/questions/46115/why-does-mppt-throttle-to-zero.html . I experience the same thing with a pair of 150/45's.

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Michael Timler avatar image
Michael Timler answered ·

I have meanwhile swapped a BLUE 150/35 with the complaint SMART 150/35.

State now: The BLUE 150/35 and the SMART 150/35 work in identical strings on the same 48V Pylontech Battery system and the same SMA Sunny Island inverter in an Off-Grid system than before.

The BLUE 150/35 works well under any circumstances without any power shedding.
Thje SMART 150/35 continues the malfunction: Under charging currents higher than 30A, it stops charging without throwing any errors like described before.

How can we proceed now?

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Michael Timler avatar image
Michael Timler answered ·

It was indeed a minor bug in the firmware, that caused this problem.

The case is now solved by a great collaboration with level3support, Daniël.


They could wipe out the bug today. It's already in the v1.49 official firmware, that can be installed through VRM, it's just not yet in Victron Connect.

Thank you very much for this great support!

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gathman avatar image
gathman answered ·

Did the problem really end up being firmware? I've got a SmartSolar 150/35 running firmware 1.59 on a 24v system (Multiplus 24/3000/70, Smartshunt, Venus running on a Pi, and a pair of 24v LiFePO4 batteries in parallel). I have a series string of panels which equals 147.1V Open Circuit Voltage (121V PMAX). Short circuit current is 9.7 amps.

If I let SmartSolar run with no restrictions on a sunny day, it will bulk charge ~30A but then cycles itself off (down to 0 current) then ramps back up at regular intervals (about every minute).

If I restrict output current to less than 20 amps, it runs stably.

Any ideas why I can't use all the photovoltaic capacity available?

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