I have a 400 ah lithium system with Victron smart batteries via a lynx bms.
Now I got a opportunity to buy 4 100 ah non victron lithium batteries with internal bms on them really really cheep.
Is it somehow possible to connect them to my system without any problem as a secondary battery bank?
Yes with a few considerations.
1. Charged and float voltages - are they the same?
2. Use a bus bar, (i am assuming since you have the shunt you have more of the lynx systeml they will have different discharge rates (internal resistances being different even if the bms is just as capable)
3. SOC can get a bit weird. But generally should be around what the smart batteries say. Not sure how it will behave if you vhange capacity in the shunt, but the rest of the batteries are not detected as I have nott done this with Victrons batteries.
Charge and discharge rates will most likely still be dictated by the smart batteries, just another thought, even though you have more capacity, because of the bms control.
Additional point to Alexandra suggestions. You can also add separate bank behind additional VE Shunt (BMV/smartshunt) which will be visible in VRM as additional DC-meter. You can see how much amps are flowing so you can get exact energy figures.
That can kind of cover part of missing BMS connection issues. Also you can see if there is deviation between banks or secondary banks is cut out because of internal BMS. There is also possibility to control additional cut-off relay to remove secondary bank automatically in case of values out of tolerance like over heat etc.
I had additional emergency reserve bank connected to main bank with relay and DC-meter and it worked nicely.
