12v Quirk and Truma 6 System

[marchie]

We have a 120Ah Lithium battery, nearly 8 months old that barely breaks sweat keeping the LED lights and 2 x low power USB sockets powered (4 cycles of Lithium recorded to date). The problem we have is when we have the fridge running on gas, a maximum of 4 LEDs at 2.15w each and the Truma heating running on gas; about 2 hours into this episode, the fridge seems to 'spike' when it calls for electric, and the LEDs lose power for about 1-2 seconds, before regaining power. Occasionally this results in the Truma Control Panel losing its settings, but often, it resumes after the spike as though nothing has happened, and we have not had the loss of power occur more than once an evening. It's almost as though the 12v system can support 2 out of 3 from LEDs, fridge and heating.
Both Lithium and Starter Batteries are pretty much fully charged at 13.3v and 13v respectively when the spike happens. When we're not using the Truma heating, everything is fine, the fridge and LEDs coexist in peace ...
If anyone has had this problem, I'd welcome any information on cause and remedy. I sit waiting for the spike to happen, then we can get on with the rest of the evening!

Steve

 

[xsilvergs]

When I first fitted our Lithiums the Truma controller clock would reset to 00:00. Lowering the Victron Solar controller voltage stopped this occuring. I could only attribute this to the battery BMS disconnecting due to high voltage.

As lowering the charge voltage stopped this happening I never confirmed it and it has never happened since.

 

[wildebus]

We have a 120Ah Lithium battery, nearly 8 months old that barely breaks sweat keeping the LED lights and 2 x low power USB sockets powered (4 cycles of Lithium recorded to date). The problem we have is when we have the fridge running on gas, a maximum of 4 LEDs at 2.15w each and the Truma heating running on gas; about 2 hours into this episode, the fridge seems to 'spike' when it calls for electric, and the LEDs lose power for about 1-2 seconds, before regaining power. Occasionally this results in the Truma Control Panel losing its settings, but often, it resumes after the spike as though nothing has happened, and we have not had the loss of power occur more than once an evening. It's almost as though the 12v system can support 2 out of 3 from LEDs, fridge and heating.
Both Lithium and Starter Batteries are pretty much fully charged at 13.3v and 13v respectively when the spike happens. When we're not using the Truma heating, everything is fine, the fridge and LEDs coexist in peace ...
If anyone has had this problem, I'd welcome any information on cause and remedy. I sit waiting for the spike to happen, then we can get on with the rest of the evening!

Steve

What do you mean when you say the fridge "calls for electric". If it is a 3-way fridge (which I am assuming it is as you are running it on gas) it will would only switch to 12V electric on engine start? And would never be using the Leisure Battery in that case either? In which case what the Fridge is doing with electric shouldn't have any connection with any leisure hab services. So that is a bit head-scratching to me.
I have come across similar issues with 12V Compressor Fridges, which do have a big spike when the compressor kicks in and if connected to a current-limited supply (such as a Load Circuit on a Solar Controller) but can't see a 3-way doing that?

Something you could do just to avoid this weird thing happening maybe is turn off the AES mode of the fridge if it has it so it will stay on gas regardless and not do a random energy search?

 

[marchie]

What do you mean when you say the fridge "calls for electric". If it is a 3-way fridge (which I am assuming it is as you are running it on gas) it will would only switch to 12V electric on engine start? And would never be using the Leisure Battery in that case either? In which case what the Fridge is doing with electric shouldn't have any connection with any leisure hab services. So that is a bit head-scratching to me.
I have come across similar issues with 12V Compressor Fridges, which do have a big spike when the compressor kicks in and if connected to a current-limited supply (such as a Load Circuit on a Solar Controller) but can't see a 3-way doing that?

Something you could do just to avoid this weird thing happening maybe is turn off the AES mode of the fridge if it has it so it will stay on gas regardless and not do a random energy search?

Thanks, David. As you know, I'm not very technical, so my description will be flawed! The 'spike' occurs when the AES fridge kicks in, looking to start its cooling work, and that seems to cause the LEDs to flash off momentarily if the Truma Heating is on at the time. I'll switch the automatic power source search of the fridge to off, to see if that works. I'll let you know how I get on!

Steve

 

[snapster]

Are you sure it’s the fridge causing this? If it’s running on gas it won’t call on the electrics when it starts, apart from the igniter pulsing, but the power required for this will be very low.
We have a lithium battery and a while ago it momentarily shut down for a split second, turning the Elektroblock unit off. This happened every 24 hours, but when the solar panel was charging the battery, it didn’t happen.
Our battery, like yours is about 8 months old on its 5th cycle.
It hasn’t happened for the past 6 weeks or so while we have been away using the van.
I spoke to the company that makes ( or imports) these batteries and they said it was the BMS causing this and it would stop doing it over time as the battery cycles increased and the battery was used more.

 

[marchie]

Are you sure it’s the fridge causing this? If it’s running on gas it won’t call on the electrics when it starts, apart from the igniter pulsing, but the power required for this will be very low.
We have a lithium battery and a while ago it momentarily shut down for a split second, turning the Elektroblock unit off. This happened every 24 hours, but when the solar panel was charging the battery, it didn’t happen.
Our battery, like yours is about 8 months old on its 5th cycle.
It hasn’t happened for the past 6 weeks or so while we have been away using the van.
I spoke to the company that makes ( or imports) these batteries and they said it was the BMS causing this and it would stop doing it over time as the battery cycles increased and the battery was used more.

I don't know! The spike/shutdown occurs when the fridge kicks in and both LEDs and Truma are on, and we're on 12v supply. It's always the fridge that triggers the problem, hence my '2 of 3 will work' comment! I'm a little sceptical about the BMS effectively learning as the cycles increase, because that sounds like some of the Dealer type BS, and because I'm a cynical old do and so, but I'll be delighted if the BMS does learn and adapts!
Looks like the Truma tripped about 1 hour ago, and resetting the clock to 00:00 (noticed at 00:16), and this is the first daytime trigger. Keeping it under observation ...

Steve

 

[wildebus]

There does seem to be some lithium batteries around that cut out momentarily for reasons unclear to the "outside world". One of the forum members here was having that issue with a brand new battery (from a new range in the country) and a replacement with the same model was the same. The resolution was a firmware update of the BMS and since then it has been perfect.

I am rather doubtful that a lithium battery BMS will 'learn' as it gets used. They tend to be pre-programmed with specific parameters and if something happens once, it will happen again in the same circumstance.

 

[nabsim]

Sounds like something not right, the AES can’t think the higher voltage of the Lifepo4 means it will try to us it does it? I thought the AES could use from habitation but I have no experience of them just pick up on bits people say.

In any event something is not right. I have had my Lifepo4 over two years now and can run all the lights in the van, compressor fridge, diesel heater, charging devices and have the tv on and nothing dips or misses. If it turns out the battery BMS won’t allow enough power out to run what you are doing it must be a fault as it sounds like you are a very low power user.

 

[marchie]

Are you sure it’s the fridge causing this? If it’s running on gas it won’t call on the electrics when it starts, apart from the igniter pulsing, but the power required for this will be very low.
We have a lithium battery and a while ago it momentarily shut down for a split second, turning the Elektroblock unit off. This happened every 24 hours, but when the solar panel was charging the battery, it didn’t happen.
Our battery, like yours is about 8 months old on its 5th cycle.
It hasn’t happened for the past 6 weeks or so while we have been away using the van.
I spoke to the company that makes ( or imports) these batteries and they said it was the BMS causing this and it would stop doing it over time as the battery cycles increased and the battery was used more.

Update: I looked at the Solar Panel History and it reported a lowest voltage of 11.23v today, which is false, because it never falls below 12.75, even with the drop down bed and water pump evening routine. Looking further back on the History, 11.23v appears on 4th March, our 1st night away on this trip, when I remember the Truma tripping. I can also see a couple of other 11v+ lows that would about coincide with power trippings, so maybe the BMS is seeing false low voltages! Just hope it does learn ... What make is your Lithium? Ours is KS Energy. If yours is the same, it might be worth speaking to Neal about any recalibration or similar

Steve

 

[marchie]

There does seem to be some lithium batteries around that cut out momentarily for reasons unclear to the "outside world". One of the forum members here was having that issue with a brand new battery (from a new range in the country) and a replacement with the same model was the same. The resolution was a firmware update of the BMS and since then it has been perfect.

I am rather doubtful that a lithium battery BMS will 'learn' as it gets used. They tend to be pre-programmed with specific parameters and if something happens once, it will happen again in the same circumstance.

Thanks, David. I'll try to contact Neal at KS Energy to see whether a Firmware update or similar is available to correct what appear to be false low voltages

Steve

 

[snapster]

Update: I looked at the Solar Panel History and it reported a lowest voltage of 11.23v today, which is false, because it never falls below 12.75, even with the drop down bed and water pump evening routine. Looking further back on the History, 11.23v appears on 4th March, our 1st night away on this trip, when I remember the Truma tripping. I can also see a couple of other 11v+ lows that would about coincide with power trippings, so maybe the BMS is seeing false low voltages! Just hope it does learn ... What make is your Lithium? Ours is KS Energy. If yours is the same, it might be worth speaking to Neal about any recalibration or similar

Steve

Our battery is a Poweroad Sub Zero. I contacted the retailer and they said it probably needs a software update at the manufactures, so on our next trip to the UK, we dropped in to get the battery checked. By then, we had been travelling for a couple of weeks and hadn’t had the cutting out problem. The battery software was checked and found to be the latest version, I cant really remember what they said about why it was cutting out, but it hasnt done it again.