where to get high cycles cells?

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SilverNodashi

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Apr 9, 2018
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I see brand batteries like Pylontech, BYD and Leoch advertise 3000 to 6000 cycles on their batteries.
Where do I get 3.7V cells with such high cycles?
 
You don't, because this kind of cycle life is pretty much exclusive to LiFePO / LFP chemistries. LiTiO / LTO is even more extreme with cycle life in the 5-digit ranges.

To a certain extent you can squeeze out more cycles out of the other 3.7V lithium chemistries by limiting the end of charge and end of discharge voltages. The downside is less usable capacity of course.
 
I agree with everything DarkRaven said

The only way to increase the cycle life of the typical 3.7 cell is to reduce the max SoC and DoD. You will greatly increase cycle life, but will also have to build a larger capacity pack for the same application requirements.

Each chemistry had their own pros/cons. There are things I dont like about LiFePO4, including density and the general quality of prismatic options.
 
SilverNodashi said:
I see brand batteries like Pylontech, BYD and Leoch advertise 3000 to 6000 cycles on their batteries.
Where do I get 3.7V cells with such high cycles?
Click to expand...

There is NASA artical out there where they got 8-9 k cycles charging to 3.8 -3.9v
 
Yes but 3.8v is in middle point. You hardly have any capacity left to use.

Go for life or lto
 
If you do want to maximize life of the typical 3.7v nominal cell without taking too much of a hit on capacity, I think a 3.5 to 3.9 is a pretty reasonable range to consider working within. 3.4 to 4.0 if you need more. Its certainly better than trying to push past 4.1v on the top end.

But if cycle life and deep DoD is the need, then LiFePO4 might just be your best bet. I dont know much about LTO so I wont comment on it.
 
Just search around its a common chemistry, and its available in a lot of different formats. Hard to help without more information.
 
CrimpDaddy said:
Just search around its a common chemistry, and its available in a lot of different formats. Hard to help without more information.
Click to expand...

Sorry, let me reword it a bit. What type of appliances would I need to look for, in order to salvage them? i.e. laptops, portable power tools, etc.
 
You find LiFe cells in expensive 12V battery packs for Lorrys as example. Camping gear. Long lasting stuff.

You dont find them in any cheap gear since LiFe generally cost 4-10x as much.
 
Thats a tough one im not sure to be honest. I guess anything that is lithium and 12v native would be a good place to start.

Perhaps the RV and boating markets would have stuff like this.

Personally I have seen plenty of used prismatic cells online new and used. I would just buy what I need, you will most likely have a difficult time finding cells for salvage as the li-ion chemistry and a lot more common in consumer goods. For powerwall, large prismatic would be my choice. Good BMS options from Batrium too.

https://www.evwest.com/catalog/index.php?cPath=4

https://www.electriccarpartscompany.com/12V-200Ah-GBS-Battery-Pack

https://www.alibaba.com/showroom/lifepo4-prismatic-cell.html
 
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