Lithium battery dropped to 10v !

[Roger S]

Hello,

We had a sneeky few days away wild camping to test our new Lithium 230ah battery and our new 500w microwave, all went very well until I got up this morning and there was no power ! The Alde heating wouldnt work, I looked at the three way fridge and noticed it had switched from gas to battery ! I tried to light the gas hob with no joy, turned on the spare bottle of gas the hob then worked as did the fridge when I reset it to gas. I assume the gas bottle ran out and then the fridge switched to battery and fairly quickly flattened it, does this sound feasable ?

Thanks Roger

 

[Hoovie]

More efficient or more effective?

more efficient as far as the fridge cooling goes. on 12V, the cooling is limited to it virtully being just a coolbox; on AC, it actually works as a fridge! If you want to call that more effective, that works as well.

A slightly bigger element I agree but uses more power than just the bigger element due to inverter efficiency.

I am referring to cooling efficency, not power efficiency

 

[Lenny HB]

more efficient as far as the fridge cooling goes. on 12V, the cooling is limited to it virtully being just a coolbox; on AC, it actually works as a fridge! If you want to call that more effective, that works as well.

Ours works fine on 12v thermostatically controlled just takes a bit longer to get down temperature as the element is a bit smaller

 

[Itsmcb]

Looks to me like your microwave and other usage has taken your battery down to about 180 amps remaining then your gas has run out during the night causing your fridge to switch to 12v and drain most of the remaining battery reserve. So not a coincidence but actually caused by the gas running out. As others have mentioned, it's unusual for the fridge to be supplied by the leisure battery but not unknown.

 

[Hoovie]

Looks to me like your microwave and other usage has taken your battery down to about 180 amps remaining then your gas has run out during the night causing your fridge to switch to 12v and drain most of the remaining battery reserve. So not a coincidence but actually caused by the gas running out. As others have mentioned, it's unusual for the fridge to be supplied by the leisure battery but not unknown.

I thought there is a heirarchy of energy sources with an AES Fridge? It will switch to 12V if available, and AC if available (can't remember which one comes first) and running on Gas is the 3rd and last option?
so If 12V was available, surely it would have been using that instead of Gas from the get-go if the Auto Energy selection was enabled?

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[Just smiffy]

Haven’t lithium batteries got something in them bms or other to stop output if they get too low..?

 

[Itsmcb]

I thought there is a heirarchy of energy sources with an AES Fridge? It will switch to 12V if available, and AC if available (can't remember which one comes first) and running on Gas is the 3rd and last option?
so If 12V was available, surely it would have been using that instead of Gas from the get-go if the Auto Energy selection was enabled?

Just seemed the logical explanation from the information given.

 

[Roger S]

I thought there is a heirarchy of energy sources with an AES Fridge? It will switch to 12V if available, and AC if available (can't remember which one comes first) and running on Gas is the 3rd and last option?
so If 12V was available, surely it would have been using that instead of Gas from the get-go if the Auto Energy selection was enabled?

My belief is they run on 240v if available then gas and 12v as the last resort.

 

[Roger S]

Haven’t lithium batteries got something in them bms or other to stop output if they get too low..?

Yes it has got that ability, but the battery is then too low to use for anything but it doesn't damage the battery at the level it has drained to.

 

[Lenny HB]

My belief is they run on 240v if available then gas and 12v as the last resort.

Other way round on Dometic 12v is the 1st choice.

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[BillandHelen]

Our Wildax is wired such that the AES fridge is wired to a 240v socket that is included in the ring of sockets that our inverter works through. Only the Truma and charger are excluded. We need to manually select gas for the fridge when using the inverter or else it thinks it’s got mains and the aes will swap. I get it can be useful if you have excess solar power, but I’m bound to forget sometime and land in trouble!

 

[Pausim]

LiFePO4 batteries are great but they are not bottomless pits. Even 230Ah of battery is less than 3 units of mains electricity. I manage fine with 100Ah and have no problem with running my 12V systems, my 230V CPAP and charging my many devices.

My personal dos and don’t are:
1) Heating, cooling and cooking are jobs for gas not 12V.
2) Charging and discharging are things I must look after and control.
3) The BMS is only an emergency device to avoid battery destruction and not something that should ever cut in.
4) Whatever I take out of the battery overnight must be replaced by the following evening.
5) Recharging is more important than discharging (bit like a bank account don’t live on credit).
Note. 1) to 5) are only possible if I understand what is going on.

 

[funflair]

Other way round on Dometic 12v is the 1st choice.

Our Dometic is only 12v first if it sees a D+ and the Flair was the same, I know you and Michael had some issue when you were experimenting with solar AES and S+ but can't remember quite what it was, was it taking S+ above 240v?

 

[Lenny HB]

Our Dometic is only 12v first if it sees a D+ and the Flair was the same, I know you and Michael had some issue when you were experimenting with solar AES and S+ but can't remember quite what it was, was it taking S+ above 240v?

Yes, I fitted a relay so that the S+ was disconnected when on EHU.