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?
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
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%.
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
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.
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
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?
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.
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
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:
and here is what we can choose in ESS assistant when seting u 2 signal BMS part of the ESS setup:
I hope you see the difference.
Best Regards,
Marek
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
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.
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
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.
@mvader (Victron Energy) Just an update I tested this again last week and the issue went away.
The low temp disconnect worked perfectly
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.
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.
the setup:
MPPT 100/50
VE.Bus BMS V2
Smart shunt 500A with its compatible temp sensor attached between it and the positive plug of 1xLFP 12v 200Ah from Victron
Cerbo GX
All working fine, I also get the low temp alarms, so the system detects the temperature is below 10 deg C set by me, excepting the low temp charging cut-off function.
The graph below shows the battery is charging even if the temperature threshold was set to 10 deg C.
That's really bad I would say, since it is not preventing the charging of the battery even below the 5 deg C limit, my system has all up to date firmware. I tried different configurations, the charging cutoff simply doesn't work.
Do I need an additional temp sensor between battery and Cerbo, for example?
Any idea what's happening? Thanks!
The VE Bus BMS V2 (the BMS) reads the internal temperature from the battery through the battery to BMS cables and the BMS control the charge based on this temperature, which has a default of 5degC. The temperature sensor on the SmartShunt and Cerbo low temperature alarm will not be involved. Connect to your battery with VE Connect on your Smartphone and you will see the low temperature cut off in there. See section 4.7 in the Smart Lithium Battery Manual.
