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Nissan Leaf (gen 1) voltage range.

SolarDavid

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C6F40023-000D-4481-AB98-DBA08BD76EEA.jpegHi Everyone.
I’m new-ish to solar power and new to this forum.

With help from a few friends, I have set up my home with solar power, powered with Nissan Leaf(Gen 1) batteries.
Was hoping you can share some ideas on the best range of voltage to keep my batteries in, to extend their life-time/cycling capacity.

I have set up my charge controllers to charge the modules up to 8v max, and shut at 7.5v.
Does that sound like a good range?

(I have set up my batteries in packs of 8 modules, 64v total/pack). My goal is to extend the life time of the batteries for as long as I can.

Should I go alter the range of charging to the battery’s?

Thanks
Dave
 
If this is the completed install, can we safely assume you're not using a BMS? If that's the case, to be both the safest for your home, and to answer your OP question, a BMS is recommended.
 
Hi Everyone.
I’m new-ish to solar power and new to this forum.

With help from a few friends, I have set up my home with solar power, powered with Nissan Leaf(Gen 1) batteries.
Was hoping you can share some ideas on the best range of voltage to keep my batteries in, to extend their life-time/cycling capacity.
These are lithium-ion technology arranged in 2s1p per metal container - e.g. 2 lithium-ion cells in series. Each lithium-ion cell will have a standard 18650 / lithium-ion voltage range of 3.0v -> 4.2v. Typically, 3.5v-3.6v is the discharge curve knee - so that's the practical cut-off voltage as there's no power/benefit in discharging down to 3.4v or 3.3v kind of thing.

Read this Battery University page - https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries - for insight into long life vs voltage ranges. Here's the chart (near the bottom of the page) that I built my system toward - I'm shooting for the 75-25% SoC line.
1637768317871.png


I have set up my charge controllers to charge the modules up to 8v max, and shut at 7.5v.
Does that sound like a good range?
These have 2s1p lithium-ion cells. So 8v / 2 = 4.0v/cell. This is great for long life. Shut-off at 7.5v / 2 = 3.75v/cell. Typically the discharge curve knee is more at 3.6v or 3.55v - so you could go a little lower but its not wrong.

(I have set up my batteries in packs of 8 modules, 64v total/pack). My goal is to extend the life time of the batteries for as long as I can.
If you do 7 modules you'll have a 14s ltihium-ion battery - which is typicall for 48v nominal and will give you the largest range of compatible equipment to choose from.

Strongly suggest you get a BMS!!! Batrium makes specific 'mons' (monitors) for leaf modules - https://support.batrium.com/article/122-leafmon that bolt on nicely. Here's a youtube from Batrium showing how it works:

I run 2 Batriums and can help answer specific questions if you get that far :)

Should I go alter the range of charging to the battery’s?

Thanks
Dave
 
Last edited:
I know old thread, but if anybody searches this up: I have been cycling my stack of 63 modules between 54v-56v (3.85v-4.0v) daily for about five years now, and the average amount of energy in and out is still 98% of when I built the stack (from “70%” cells).

I save the 54v to 45v (disconnect) range for if the grid power goes out, which has happened twice.
 
I know old thread, but if anybody searches this up: I have been cycling my stack of 63 modules between 54v-56v (3.85v-4.0v) daily for about five years now, and the average amount of energy in and out is still 98% of when I built the stack (from “70%” cells).

I save the 54v to 45v (disconnect) range for if the grid power goes out, which has happened twice.

@copec thanks for the update! I'd love your feedback for this idea:

I'm considering what batteries to use for my Sol Ark 15k System. The video @OffGridInTheCity posted looks fantastic!!

With a $50 cost for each monitor module and ? cost for the main monitoring system that BMS is going to add up fast.

What could I expect for cost for Leaf modules?
 
The individual leaf modules aren't really as prevalent as they once were. It seems a lot of companies are sourcing the whole used batteries for ESS directly from Nissan now, so they really aren't being bought by the resellers that break them up anymore. You'll see a batch for a reasonable price pop up every now and then, so it's sort of a wait and jump on it game. Otherwise, the best way is to get used whole batteries out of wrecks.

I started out with two kits based on leaf modules, but ended up buying a couple of wreck batteries and manually dividing them up to get my stack of modules.
 
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