question

duane avatar image
duane asked

Low Temperature Cutoff not working

Hello

I have a Smart Shunt with latest firmware with a ve.smart networking setup to 2 MPPT 100/50 and 4 Ip22 12/30 chargers.

Everything is using the Lifepo4 profile with a low temp cutoff of 5 degrees C

It simply doesnt work with the charging continuing at 4 degrees C

Everythings firmware is up to date and the synchronised charging works perfectly but alas not so the low temperature cut off

Any ideas as to why?

MPPT Controllerssmartshunttemperatureip22
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4 Answers
Paul B avatar image
Paul B answered ·

Hi the smartshunt does not have a inbuilt temp sensor, nor do the Smartsolar regulators have a battery temp sensor, so what device are you using thats got a temp sensor connected to the battery.

Normally the BMS should turn the charging off itsself if the temp gets to low,

however I would have thought, that you could add a bluetooth Victron sensor to the side of the battery and add it to the bluetooth network then the devices would have a temp sensor at the battery and they then should be able to control the charging and turn off at low temp

https://www.victronenergy.com/accessories/smart-battery-sense


9 comments
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Hello @Paul B ,

Do you know of the method that uses the MultiPlus-II temp sensor to stop Lithium battery charging when temperature is below 5C?

BMS I have has temperature sensor but is using 2 signal BMS assistant to communicate with MP-II. Problem arises when BMS sends "do not charge" signal to MP-II (when is to cold) and MP-II always assumes that it means "battery full" and SOC is set to 90% even when is only 20%.




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It would help if you told us the complete system configuration, and not just parts, as NOwhere in your original post do you mention a Multiplus ii SO WHAT else is connected

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Hi @Paul B ,

I am not the original poster, @Duane is.

I did not thing that information about the rest of the system is needed but here it is:

5 x MP-II 3000 + 1 x ES-II GX 3000 (3Phase/parallel configuration)

1 x MPPT 150/35

1 x smartshunt

48V LFP Winston battery 16 x 200Ah

1 x 123smartBMS connected to ES-II (Aux1 and Aux2) and 2 signal BMS assistant loaded.

ESS assistant loaded.



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Maybe resurch the victron VE BMS unit as that unit has 3 control circuits

1 low cell trigger use the 123 BMS for that

2 High cell trgiger use the 123 BMS for that

3 the third Black wire has a temp control

I have never used the temp control but you could use some form of temp switch to trigger that

the VE bms unit has 3 looped circuits and if any one goes open circuit it signals the multi plus the via the VE bus to stop but I think under temp may cause both load and charge to turn off

we also use the 123 smart for our primay BMS, doesnt that also open the load and charge relays if there is a over or under temp condition. not sure as where we are temp is never a issue.

Also 123 smart has a Extended module option that may give you that extra control by Can bus. and via extra programable relays again I have not used this option so you would need to check it out


Another Idea would be add a Fridge digital control thermostat and use that to open the charge input on the 2 signal input if temp goes low



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NOTE Victron does not support the use of the VE-bms unit on any other battery than the Victron batteries,
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Hi @Paul B,

Maybe resurch the victron VE BMS unit as that unit has 3 control circuits

VEbusBMS is only for Victron batteries

we also use the 123 smart for our primay BMS, doesnt that also open the load and charge relays if there is a over or under temp condition. not sure as where we are temp is never a issue.

I would prefer not to completely disconnect battery from bus-bar and from Inverters, because only charging is not allowed below 5C. 2 signalBMS assistant (inside ESS assistant) is used instead.

Also 123 smart has a Extended module option that may give you that extra control by Can bus. and via extra programable relays  again I have not used this option so you would need to check it out

123smartBMS Extended module does not use CANbus protocol compatible with Victron. Additional relays do not provide the alternative.

Another Idea would be add a Fridge digital control thermostat and use that to open the charge input on the 2 signal input if temp goes low

But this is not different from opening the charge input by 123smatBMS when temperature is below 5C.

The problem is, that the MP-II takes this signal as "battery fully charged", not "temperature to low", and as a result SOC is set to 90%. If you load "2 singnal BMS assistant" you can select the option that would prevent this from happening, but when you use "ESS assistant" that option is missing.

The question is, why GX cannot use MP-IIs temperature sensor to control charging of LFP battery (stop when below 5C) when it reads that sensor and knows exactly what the temperature is. You can see the battery temperature on the VRM, that is from this sensor?

battery-temp.png

There is also temperature sensor for smartshunt that would generate alarm on low temperature (you have to buy it extra), but I am not sure if it is not as useless, for LFP batteries, as the one that comes with MP-IIs. On top of it I have 6 temperature sensors that came with MP-IIs and they are not compatible with smartsnunt. :(

What additional hardware Victron wants me to buy to fix the low temperature charging problem?

Winter is coming and I would like to solve it before freezing days.


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battery-temp.png (23.3 KiB)

Hello @MarekP ,

If I remember correctly, when I set up the 2 signal assistant for my system it did offered the option to select "do not adapt state of charge" when it receives a "battery full" signal. Mine is an ESS system, strange that yours does not allow this? Cheers, Leslie

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Hello @Leslieanne

You are correct.

There is an option "do not adapt state of charge" in 2 signal BMS assistant, but in ESS assistant that option is gone.

Here what we can choose in 2signalBMS assistant setup:

tsbms1.jpg

and here is what we can choose in ESS assistant when seting u 2 signal BMS part of the ESS setup:

ess2.jpg

I hope you see the difference.

Best Regards,

Marek

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tsbms1.jpg (153.4 KiB)
ess2.jpg (132.4 KiB)
Hi, yes you are spot on. Thanks for putting me right. I set up my system over a year ago. Maybe an update to ve config since then has changed things, or my memory is dodgy...more likely the latter!!
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duane avatar image
duane answered ·

Hey @Paul B

Thanks for your response I have purchased the temp sensor for the Smart Shunt and the VE Smart networking notification says "Transmitting battery voltage and temperature sense. Transmitting battery current sense"

All of the chargers are joined to the VE Smart networking and display the temperature and voltage from the Smart Shunt network.

They all say " I am receiving the following data from the network Battery Voltage and Battery temperature"

The lifepo4 profile sets a low temp cut off of 5 degrees C

All looks good and well designed it just doesn't shut off at 5 degrees or below

I have removed the network and reinstalled it but havent had a day cold enough to test it again.

Might be just a firmware update away

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Hi @Duane

To test it you can set the low temp much higher and test it at todays temperatures.

I would be very interested in your results because I was about to buy this temperature sensor for my SmartShunt to fix my low temp problem.

Seeing your problems I decided to hold off.


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@MarekP

I will try that tomorrow and see if it works after the network rebuild

Let you know

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duane avatar image
duane answered ·

@MarekP

Sorry I couldnt do the test as the max temp I can set is 10 degrees C

The ambient temp is over 10 degrees so I cant test it

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Hi @Duane .

It is OK. Thanks for trying.


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If you have some ice around you can do the test any moment.

Easier as to wait till is colder


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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi all, we'll be looking into this in the coming few weeks to see if we can reproduce it. Thanks for reporting. Matthijs / Victron.

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@mvader (Victron Energy) Just an update I tested this again last week and the issue went away.

The low temp disconnect worked perfectly

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Hi @Duane , we did find a bug: the low temp cutoff in the IP22 doesn’t work all the time.


Not good at all. We’ll release a firmware update for the IP22 shortly. I expect that it will be included in a VictronConnect release in 2 to 3 weeks from now.


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duane avatar image duane mvader (Victron Energy) ♦♦ ·
@mvader (Victron Energy)

Thanks for taking your customers seriously and genuine looking into this issue.

This behavior is quite rare and is one of the reasons I have changed everything to Victron sadly I had to abandon one of our premium Australian manufacturers because they didn't take me seriously on one issue.

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You're very welcome, and thank you as well!
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mrbuffer avatar image mrbuffer mvader (Victron Energy) ♦♦ ·
I have two Multiplus II units running split phase. Both units have temperature sensors and I have tested both down to -1 degrees Celsius. The units continue to charge below the 5C threshold. Is there a firmware update to fix this? Are there any workarounds if not (I have a Cerbo GX)?
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