Multiple Inverters with one battery bank

[unkyjoe]

Here is my situation

Victron Multiplus II 48v 5000va unit running 120v critical loads, cerbo GX, using ESS and keeping the batteries fully charged.
EG4 6000XP 48v unit running 3-220v mini splits and one 120v mini split. SBU setting as close as I can get.

One 48v battery bank consisting of 1 server battery, 2x24v in series for another 48v battery, diy 48v battery, all 5.1 kw in size.

One victron shunt load side connected to the Victron busbar - and the other to another busbar with all battery negatives hooked together.

So I want to share the battery bank between the two inverters, I am looking for opinions on the best way to do this, should I choose the Victron to keep the batteries charged, or should I use the EG4? Or both, and limit thier charge currents, the battery bank will ultimately determine when the batteries are fully charged, I am just wondering if anyone has run into this issue before?

I also want to make sure that I position the EG4 cables on the right location of the Victron shunt so it measures the current going in and out of the EG4 as well as the victron.

Thanks in advance

 

[ricardocello]

Given the frankenstein construction of your battery bank (not a criticism!) , what do you believe the maximum safe charge current should be?
The server battery is likely between 30-50A, so maybe 100A for all combined?

Is the server battery the controlling BMS, or are you running open loop?

 

[Adam De Lay]

I've got a similar setup right now and I have both systems charging the bank of batteries. It's really no different than having multiple charge controllers without communication. You just want to make sure that your batteries are all on the battery side of the shunt and the loads/chargers are all on the other side.

 

[unkyjoe]

I've got a similar setup right now and I have both systems charging the bank of batteries. It's really no different than having multiple charge controllers without communication. You just want to make sure that your batteries are all on the battery side of the shunt and the loads/chargers are all on the other side.

Thanks, that's what I thought, I tend to over-think things so I thought I would ask the experts here.

P.S. That EG4 is chugging along and running my entire cooling load, we have had a couple of 85+ degree days and this thing handles all 4 of these mini-splits without an issue, the 220v units pull about 7.5 amps each at 240v. The 120v unit pulls about 1200 watts at full bore, but these are inverter compressors so that helps avoid the huge surge currents.

 

[unkyjoe]

I've got a similar setup right now and I have both systems charging the bank of batteries. It's really no different than having multiple charge controllers without communication. You just want to make sure that your batteries are all on the battery side of the shunt and the loads/chargers are all on the other side.

I don't have the battery coms hooked up to one another, nor will I in the future I believe, I limit my charge current on the victron to 30amps and the same limitation on the EG4, the victron could pull in theory 73 amps from the battery bank at a full 3500watt load. The EG4 could pull the same under load, although it has never gone higher that 3000watts so about 63 amps at 48v from the batteries.

 

[unkyjoe]

Given the frankenstein construction of your battery bank (not a criticism!) , what do you believe the maximum safe charge current should be?
The server battery is likely between 30-50A, so maybe 100A for all combined?

Is the server battery the controlling BMS, or are you running open loop?

I don't have the battery coms hooked up to one another, nor will I in the future I believe, I limit my charge current on the victron to 30amps and the same limitation on the EG4, the victron could pull in theory 73 amps from the battery bank at a full 3500watt load. The EG4 could pull the same under load, although it has never gone higher that 3000watts so about 63 amps at 48v from the batteries.