liamharry
Member
You battery aficionados out there probably know this and can tell me whether I am going totally off plot, but came across this bit of info written Jim Harrison back in 2018, a guest blogger at Lincoln Technology Communications about the Tesla battery cell. He was writing about the new 2170 battery.
In effect he is saying a 70mV reduction in charge voltage reduces capacity by 10%. My own battery being capped by 100mV’s, which has resulted in almost 12% reduction in capacity.
So if the article suggests that a battery charged to 4.2V can cycle 300 - 500 times, then a battery that is generally charged to no more than 3.90V (assuming capped or voluntarily) can be cycled between 2,400 - 4000 times?
I know I am over simplifying this and not taking into account specific Tesla cell chemistry, but - I am not sure that means if eg you have a 100% SoC range of 256 miles and charge from 100% and discharge to 0% every time the battery/pack will only last (256X500) 128,000 miles, but likewise if you only ever charged to 3.90V (providing 220 miles in my case) and discharge to 0% each time that the battery would last (220X4000) 880,000 miles.
Is that why Tesla would like to drop (sorry .. for some of us has, have capped) the max voltage by 100mV on our older packs.
In effect he is saying a 70mV reduction in charge voltage reduces capacity by 10%. My own battery being capped by 100mV’s, which has resulted in almost 12% reduction in capacity.
So if the article suggests that a battery charged to 4.2V can cycle 300 - 500 times, then a battery that is generally charged to no more than 3.90V (assuming capped or voluntarily) can be cycled between 2,400 - 4000 times?
I know I am over simplifying this and not taking into account specific Tesla cell chemistry, but - I am not sure that means if eg you have a 100% SoC range of 256 miles and charge from 100% and discharge to 0% every time the battery/pack will only last (256X500) 128,000 miles, but likewise if you only ever charged to 3.90V (providing 220 miles in my case) and discharge to 0% each time that the battery would last (220X4000) 880,000 miles.
Is that why Tesla would like to drop (sorry .. for some of us has, have capped) the max voltage by 100mV on our older packs.
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