[RE-wrenches] Different LFP Batteries in Parallel

[Dave Angelini Offgrid Solar]

Does the client know that they can't blame you for doing something that 
has chances of being a bad choice?

Can the client keep track of two different Soc and be responsible about 
it?

I would also look into how a home insurance policy would react to a 
claim.

Dave Angelini Offgrid Solar
"we go where powerlines don't"
    [1]https://offgridsolar1.com/ [2]  [1]
e-mail  offgridsolar at sti.net
text 209 813 0060

On 2025-07-14 6:45 am, Jason Szumlanski via RE-wrenches wrote:

> They are Lithionics.
> 
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
> 
> On Mon, Jul 14, 2025, 9:33 AM jay via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> Hi Jason,
> 
> can you let us know what the old battery is so we can dig up the specs 
> and see if there would be any issues.
> 
> There are a few odd ball like simpliphi which while a 51.2v has a very 
> narrow window for operation compared to most other prismatic cells.
> 
> jay
> 
> On Jul 14, 2025, at 5:07 AM, Jason Szumlanski via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> 
> There are never-ending videos on YouTube showing different brands and 
> capacities of LFP batteries working in parallel. I have never tried it 
> myself, and every instinct says don't do it, but I have a situation 
> where it would be very helpful.
> 
> I have a client with an older 60 kWh battery that is discontinued and 
> incompatible with any other battery from the same manufacturer. It has 
> a BMS with a 51.2 volt nominal rating. They need another 20 kWh of 
> capacity. It is too costly to scrap the existing battery and start 
> over, and the existing battery has been tested and confirmed to hold 
> very close to its rated capacity.
> 
> What is the real deal on mixing and matching? Is anyone doing this 
> safely and successfully? I wonder what the battery manufacturers say 
> about it.
> 
> Jason Szumlanski
> Florida Solar Design Group
> 
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