Multiple Battery Banks

[Cuemaker]

Is there a limit on the # of battery banks that can be added to a system?
I have 2 - 48v-280ah battery banks now & have plans to expand.
They are connected to 2 inverters, 6kw & 4kw.
Everything is working great but we need more storage capacity.
We would like to be able to run 2kw for 24hrs, that would take about 7 battery banks.
I thought about splitting up the inverters & have 2 sperate systems, put 4 battery banks with the 6kw & 3 on the 4kw.
If there is a maximum # of battery banks that can be added to a system I can't find it.
Thanks

 

[sunshine_eggo]

Is there a limit on the # of battery banks that can be added to a system?
I have 2 - 48v-280ah battery banks now & have plans to expand.
They are connected to 2 inverters, 6kw & 4kw.
Everything is working great but we need more storage capacity.
We would like to be able to run 2kw for 24hrs, that would take about 7 battery banks.
I thought about splitting up the inverters & have 2 sperate systems, put 4 battery banks with the 6kw & 3 on the 4kw.
If there is a maximum # of battery banks that can be added to a system I can't find it.
Thanks

Some of the server rack batteries have some arbitrary limit due to communications limitations between them.

Most manufacturers will limit you to 3-4 parallel batteries.

For DIY and non-comms, it's about current management. You can build a big honking multi-battery bank, but the challenge becomes getting the batteries to share the current equally. The best method is to connect all the batteries in parallel via bus bar. Once up and running, you verify that all batteries are working within specification via a DC clamp ammeter.

 

[Daddy Tanuki]

Is there a limit on the # of battery banks that can be added to a system?
I have 2 - 48v-280ah battery banks now & have plans to expand.
They are connected to 2 inverters, 6kw & 4kw.
Everything is working great but we need more storage capacity.
We would like to be able to run 2kw for 24hrs, that would take about 7 battery banks.
I thought about splitting up the inverters & have 2 sperate systems, put 4 battery banks with the 6kw & 3 on the 4kw.
If there is a maximum # of battery banks that can be added to a system I can't find it.
Thanks

not as long as you follow proper cabling and fuseing/disconnect, interconnect practices.

I currently have three large banks two (2) of them are 16s packs made of large 400 a/h winston cells, and the last bank is a 3p16s mix of older calb 180 se's that I started with.

originally the system was four (4) 16s banks with the calbs.

you will notice that some the different banks SOC with vary wildly. part of it is the simple fact that some of the banks will discharge and or charge faster than others. Part of this is the inconsistency in which the BMS itself calculates the SOC. If this worries you get an actual shunt system for each pack and rely on what each individual shunt tells you... not the BMS apps. other than this build as many as you want I have 70Kw total on a nominal 48 system and I only use about 10~15% overnight in the winter. gives me a solid 3-4 days backup in case of snow or poor production.

 

[Quattrohead]

I had 11 connected together over various PowerPro and DIY batteries with three different types of BMS, they all shared reasonably well together.

 

[Cuemaker]

Some of the server rack batteries have some arbitrary limit due to communications limitations between them.

Most manufacturers will limit you to 3-4 parallel batteries.

For DIY and non-comms, it's about current management. You can build a big honking multi-battery bank, but the challenge becomes getting the batteries to share the current equally. The best method is to connect all the batteries in parallel via bus bar. Once up and running, you verify that all batteries are working within specification via a DC clamp ammeter.

I use a bus bar for the battery banks, each bank has a fuse & switch.
Then from the battery bank bus bar to a fuse & switch to the main bus bar with the charge controllers & inverters.
Works great with 2 battery banks, plan is to add a new battery bank every 3 or 4 months, as funds permit.