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andaroundwego avatar image
andaroundwego asked

Low temp shut off with no temp sensor!

Hey guys, I have an MPPT 100/30, an IP22 mains charger and a BMV712. All updated to latest versions and networked together. A few months ago both the MPPT and the mains charger decided the battery was -1 C and shut off all charging. Both the chargers were saying the were receiving temp from from the BMV712, however it said it was sending voltage and current only (no temp sensor fitted, aux set to none). After being really annoyed at the batteries dropping to 40% I changed the setting and disabled the low temp cutoff.


Now a few months later I just noticed the mains charger had shut off 48 hours ago as the batteries hit 25% and my low SOC alarm went off. It had gone back to 5 degrees setting and saying it was -1.


This is just insane for a supposed good quality system and not impressed my fairly new lithiums have been let drop to 25%.

Temperature Sensor
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Alexandra avatar image Alexandra ♦ commented ·

@AndAroundWeGo

do you every need the low temp cut off?

if you dont you can disable the option in the lithium battery profile

What firmware are you running on the devices?

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solar-mann avatar image
solar-mann answered ·

Discovered this same issue today on a customers RV. 150/100 smart solar MPPT and smart shunt. No temp sensor installed but the MPPT is showing -1c. I know I can disable low temp protection but I’d like to know why this issue is happening.

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jetlag avatar image
jetlag answered ·

Again, this is an old story. A lot of people reported this already (including me). There are a lot of threads to this topic if you want to have some more information to that.

Short summary: As far as I follow this topic, this behaviour will appear only once and then never again (at least in more than a half year). So just restart your MPPT by switchig off the PV and battery for a moment and I should work properly again.

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andaroundwego avatar image andaroundwego commented ·

I did search and only found one topic on it. This is the second time now for me in the last year, and nearly killed my batteries as I hadn't noticed it wasn't charging for 48 hours (I don't normally check it's charging every day when on mains power). 2 x 140ah lithiums are not cheap, so I didn't buy a cheap charging system and spent a little more on a decent brand that shouldn't randomly decide to not charge and run my batteries flat. We are on the road full time in the caravan so dead batteries mean no fridge, no freezer, no lights, no internet etc.. the fact that you say it's been around for a while and reported many times just makes it worse that it's still happening. I reported it last time and all ingot was an email frommthe local saying you can send it in to be looked at but it will cost if there is othing wrong found.


Sorry, it's just not good enough.

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jetlag avatar image jetlag andaroundwego commented ·

Don't wanted to blame you, but you konw, sometimes people just open a new thread before they search for the already given answers. I'm kind of interessted in this topic as I also had it two times already but with different values.

I also did some firmware updates in the meantime what could have solved the problem.

But yes, I understand you completely. If you are not willing or able to check this on regular basis, then you might run into problems.

The point is, that it seem still to be too seldom to be an urgent topic for Victron.

From that perspective it is always good to report this findings and to collect them giving Victron a better chance to understand the problem as well as to make some preasure on Victron to investigate this topic.

But if people just open new threads every month, then it gets lost in my opinion.

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andaroundwego avatar image andaroundwego jetlag commented ·
On te contrary, the more threads opened with the same fault, the more obvious it becomes that its a wide spread issue and not a one off oddity. Through this thread I have now been able to discuss directly via email with a level 3 engineer and provide screen shots and operational logs of the issue ocurring, assisting them in being able to identify and rectify the issue once and for all.
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mkuiken avatar image
mkuiken answered ·

Hi @AndAroundWeGo ,

I'm sorry to hear that you ran into this issue. Please be assured that this issue defnitely has our attention but unfortunately we've not been able to replicate it ourselves as of yet.

One thing that might help us understand what is going on, is the creation of a service report while the issue is still happening i.e. while the charger is still reporting a temperature below the low temp cutoff even though there's no temperature sensor in the VE.Smart Network.

Unfortunately, though perfectly understandable, in order to fix the issue the chargers/smartshunt are often reset before a service report is created. Like said, perfectly understandable but we lose the possibility to retrieve information from the system in fault. See here to find out how to create a service report (one report for each device in the VE.Smart Network).

Regarding the changed low cutoff temp setting, (temporarily) changing the battery preset might indeed undo the changed low temp cutoff setting. It's a long shot, but maybe a service report will tell us how/when the setting was changed (back). Feel free to create one if you want me to look into that.

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andaroundwego avatar image andaroundwego commented ·

@mkuiken Well that didn't take long! Next day the MPPT and IP22 are both reporting battery temp at -18 degrees, IP22 has shut down charging but the MPPT didn't (but was reporting -18). Both chargers were saying the VE networking was transmitting the temp, the BMV712 said it wasn't. Took screen shots of them all after doing the report, however after opening the BMV712 to check the Aux setting the temperature sending stopped and both chargers kicked back in. But I did capture it in time and hope it helps.VictronConnect_report(1).logscreenshot-20230824-153328.jpgscreenshot-20230824-153348.jpgscreenshot-20230824-153405.jpgscreenshot-20230824-153500.jpg

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victronconnect-report1.log (287.3 KiB)
mkuiken avatar image mkuiken andaroundwego commented ·
Hi @AndAroundWeGo ,

Thanks for the service report and screenshots! We've been looking into it already but will need some more time to gather all possible information from it.

Btw I've also sent you a message via email.


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andaroundwego answered ·

Thanks for that. Ok, I can turn the low temp cut off back on for both chargers, monitor daily then do a report if/when it faults. Happy to do that (that's sort of my thing... been a beta tester for many products and software over the years).


Further thinking through the problem I believe it's the BMV712, as the first time it happened both the IP22 and the MPPT both stopped charging at the same time, both reporting they were receiving temperature from the BMV712. When that happened the network information on both chargers was reporting it was receiving voltage, current and temperature from the BMV712, but the BMV712 said it was transmitting only voltage and current. If it was only one of the chargers I would obviously point the finger at it, but since both did the same thing simultaneously the only common factor is the BMV712.


Wish me luck!

Cheers, Dave.

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Cristian avatar image
Cristian answered ·

it is a network problem ve.smart & smartshunt


https://community.victronenergy.com/questions/203617/mppt-displays-negative-temp-and-stops-charging-eve.html?childToView=225106#answer-225106

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andaroundwego avatar image andaroundwego commented ·
But still no answer on that thread either...
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jetlag avatar image
jetlag answered ·

I agree with your analysis, that the BMV seem to be the bad guy sending a temperature.

The other way round could be, that the other components expect to receive a temperature, but there is nothing, and they set something weird. I come to this conclusion, because some people reported the same behaviour while they have no component in the system that would be able to measure the temperature at all. But the parallel behaviour of "independant" charges seem to have the same source to me as well.

Hope, that with your feedback and infos and screenshots Victron will be able to tackle this problem (more) effective.

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andaroundwego avatar image andaroundwego commented ·
Yes, your thought does have merit, but now the third time the problem has ocurred, and the third time both chargers have reported the same temperature, which has been different each event (-1, -5 and -18). Would indicate there is definitely something external to the chargers telling them this temp. Since they are networked with the BMV712 and nothing else, it does point to the BMV712. When I logged in to look at both chargers, I could see they were not charging. When I logged into the BMV712, suddenly both chargers fired up again, without making any changes! I have now sent a few logs to Victron, so hopefully this will help.
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