Any steering at the right way please

[Vincenttor]

Well first of all i am asking this question for my dad, he owns a RV and put a new battery in the RV as household appliance battery.

The batteries are bought on aliexpress, those are the known blue cells 4 x Lifepo4 and should be 320Ah each.
The BMS he is using is a Dalu 200A BMS.

My dad and his neighbour have done the same steps, seems to work good in the neighbours his RV but when the voltage drops below 11.6 V its all dark and need some time before it is charged/working again.

My question is, since we can't get a grip on the seller of the aliexpress batteries ( store is 404 error now so gone with the wind)

Are these the right settings for the BMS or can we lower it , or would this damage the cells.
Anybody that could push us in the right directions ?

Thanks in advance

Here are some screenshots of the BMS:

 

[Hans Kroeger]

The sum volt low protect is set to 11.6 V. This is a reasonable value which reflects an "empty" battery. The BMS does what it should do. It disconnects the load from the battery. You may have to set the cell volt high protect voltage to 3.7 V. In addition you should make sure that the end of charge voltage of your charger is 14.4 V maximum assuming the 4 cells are well balanced. Otherwise you may have a problem to charge the Battery to 100 %. Adjust your charger to 14.2 V if you can. Gives you more margin to hit the 3.7 V high protect voltage.
Also make sure that the active balancer is active only above 3.4 V and goes to sleep mode below that voltage.
Good luck, Hans

 

[Vincenttor]

Thank you for the explaining reply Hans,
we will keep the settings then for now, hope it will discharge a bit more to see how it reacts.
There is another battery in the whole system what we suspect to be the problem telling the BMS that the voltage is to low, seems to be connected but we can't find out yet how and what wire.
Since the RV is at home we can run some tests now.


Thanks again for the detailed explanation
Vincent.

 

[Rocketman]

One other bad setting is on the last photo, (assuming these are standard LiFePo4’s),
The chg low temp protect should be 0C (or maybe even +1C or +2C).

If you charge cells below 0C or 32F bad thing happen.