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using different battery types and banks to power inverter

gnoeld

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Apr 11, 2022
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Can I connect one inverter to two seperate battery banks that are independent from one another? One bank is 1200ah of lead acid and the other is 600ah Iron Phosphate each with their own CC
 
If you connect both battery banks to one inverter then that is the same as connecting the two battery banks together in parallel. You do not want to connect those two banks together in parallel due to their different chemistries and their different voltage curves.

Or do you plan to have a way to switch between the two battery banks so only one is ever connected at any one time?
 
If you connect both battery banks to one inverter then that is the same as connecting the two battery banks together in parallel. You do not want to connect those two banks together in parallel due to their different chemistries and their different voltage curves.

Or do you plan to have a way to switch between the two battery banks so only one is ever connected at any one time?
My original thought was t o connect the inverter directly but I had a funny feeling it would act to connect the banks together. Thanks for clarifying it for me. switch of some type would seem to make the most sense
 
The system is designed to be a backup for the grid
I am getting lifpo batteries and already have acid.
Looking at the alternatives of how to best utilize the batteries
 
Would routing one bank through a charge controller or dc-dc charger work? Amps would be limited from the controller
 
The system is designed to be a backup for the grid
I am getting lifpo batteries and already have acid.
Looking at the alternatives of how to best utilize the batteries
There are several threads on combining lead acid with LiFePO4 batteries. Do a search, these are just some but there are others..


If the lead batteries are SLA then it's pretty straightforward, a bit of adjustment to charging profile. But make sure each bank is separately fused. There is also a device which can help manage by switching the lithium bank in and out depending on the circumstances:

I have never used it nor any affiliation with them.

I just post all this as I will be doing exactly this, adding 200 Ah of LiFePO4 to a 424 Ah SLA bank (48 V) which at present is my home backup power system, but with the addition of LiFePO4 I plan to use it for running more loads and regular cycling.
 
My original thought was t o connect the inverter directly but I had a funny feeling it would act to connect the banks together. Thanks for clarifying it for me. switch of some type would seem to make the most sense

If switching just be careful to use a specific charging profile for lead acid and LiFePO4, respectively, as they have different charging behaviors.
 
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