Repurposing EV batteries for energy storage
 

Nissan Leaf battery modules are already $200/kWh.

I see them on ebay, modules are 2 cells, I'm assuming 24ah and people want $90 to $100 for them.
That's still $700 for 1 useable KwH if the cells actually hold 24ah and they are 24ah.

Now if you bought an entire used battery that would be $200 to $400 KwH then you still have to take it apart and rearrange the cells for normal useable voltage unless you have a lead on an inverter that will convert leaf 400vdc to single phase AC?

Each module is 2S2P for about 62Ah.

I can buy a used Leaf pack locally for $3000. That's $125/kwh. Of course there's no telling what level of charge ability the pack has remaining until tested. I have seen wrecked Leafs go for around $2000 on auction sites. But then you'd have to transport the car, pull the pack, and get rid of the rest of the vehicle. On the other hand if you were doing a conversion and the motor was still intact you could swap out the Leaf parts into your own build. JJ

That still leaves you with a battery with 400vdc potential to take apart.
It doesn't bother me one bit.
When I replace the battery in my leaf I was going to eat the deposit and harvest the modules for my projects and sell the rest individually.

This girl will show you how to tear down a Nissan Leaf pack to get at the modules:
https://www.youtube.com/watch?v=oWNnnIHVsCU
She kind of shows off how strong she is:
https://www.youtube.com/watch?v=AHLjdjAaMj4

That actually looks pretty easy.

Take the leaf battery when it loses 2 or 3 bars of battery life, replace it then harvest the leaf modules out of the old battery and repurpose them for 48v.
The first 4 cell LiFePO4 charge controller came out about 2013 and I believe the first 48v LiFePO4 charger is out already.

The Leaf cells are not LiFePO4 but LiMn. 4.1V full charge is not a common voltage for a BMS so I ended up designing my own for my project.