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Old 12-08-2019, 01:53 PM
glend (Glen)
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Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
A comment on how long lithium ion batteries can last. Experience with electric bikes, which might have a typical 36V 10AH li-ion battery, show that you can double the lifespan of the battery simply by not fully charging it. Max charging causes plating of the negative electrode, limiting its potential life span. By undercharging you can double the number of charging cycles you get out of the battery, as you reduce negative electrode plating risk.
So in the case of 36V 10AH battery pack, which typically could be expected to function well for 400 charge cycles, you can up the life span to 800 charge cycles by under charging. If the 18650 Lithium ion cells have a max voltage of 4.2V, just stop charging at say 3.9V.
You also don't need to charge after every trip, provided you still have enough battery charge distance for your next trip,etc. Plugging in the charger after every trip to top it up has reduced life span implications. This should be true of electric car batteries as well as bikes as the chemistry is exactly the same.
Now the vendors don't tell you this because they want to sell you a new battery in a few years.
By association, you could possible double the life of your home Power Wall battery system by finding a way (hack circuit) to stop the charge cycle before negative electrode plating becomes an issue.

Utube video on this subject here:

https://youtu.be/zQ_y3nKU360

This document explains the optimal cell charge voltage for life extension is 3.92V.

https://batteryuniversity.com/learn/...ased_batteries
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