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Yuasa LEV40 batteries
#1
Hi

I recently got a batterypack from a 2016 Outlander, which contains 80 of the Yuassa LEV40 cells. I will be using 20 or 40 of them in an ATV conversion, but I have some trouble verifying the correct data on these cells. In a datasheet I found on secondlife-evbatteries the operational voltage range are stated to 2.65-4.0V. Unfortunately I dont have a fancy charger so I can get nice graphs, but I have tested one cell with an ISDT charger I have. These are supposed to be 40Ah cells. From 4.0-3.2V discharge I get 24Ah. From 3.2-2.8 I only got another 0.5Ah, so obviously there are no point in draining them that deep in daily use. However, when I charged them to 4.05V I got another 6.5Ah from 4.05-3.2V. The cells came from a low mileage car (~16K km), so I do think they should hold a little more than 24Ah. Im suspecting the voltage range in the datasheet I found are a little off.

When I take a look at the datasheets for the LEV50 cell, which is supposed to be more or less the same cell with a higher capacity, the datasheets state oprerational range from 2.75V to 4.1V. There are also some official data from Yuasa that confirms the voltage range, which unfortunately, I cannot find for the LEV40 cell. 

I found a few projects on this site with powerwalls that is using these cells, so I'm very curious if someone has any experience with these cells, and what kind of voltage they are running them at. I would be very thankful for any info about these cells.

Steinar
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#2
You can operate them as low as 2.75V but they will not provide sufficient current when below 3.3V. You should charge them up to 4.0/4.1V and cut-off at 3.3V on the discharge side.

The 4.0 recommendation is just to increase lifetime of cells, you can definitely charge over that.
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#3
The LEV40 datasheet you're referring to states that it lasts 5500 cycles when used in the 2.65v ~ 4.0v range. That tells us that the voltage range is significantly reduced in order to increase cycle count.
The 40Ah capacity stated could be when using the full voltage range of 4.2v(?) ~ 2.65v, whereas the usable capacity with the conservative voltage range is much closer to your tested 24Ah.

The discrepancy makes sense when you consider that the Outlander PHEV is advertised as having a 12kWh battery, even tough the actual usable capacity is just 9kWh.
Modular PowerShelf using 3D printed packs.  40kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
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#4
Alright, thanks for the responses! I think I will tey to charge it to 4.1V and measure the capacitt down to about 3.3V. As long as I can get close to 35Ah I think the range will be acceptable with just 20 cells in series. And it is a LOT easier than fitting 40 cells in the ATV. I highly doubt it will live to see 5000 cycles anyway Wink
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