Tesla and how they treat their batteries

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Oberfail

Member
Joined
Jun 22, 2021
Messages
160
During my nightly research about batteries, trying to find proper documentations about Li-ion batteries, I stumbled upon some topics from Tesla.
Probably everyone here knows them and some might even know, how well their batteries actually age. (85% capacity after 320k km / 200k miles)

Their 1st Gen Tesla Roadster, the converted Lotus, already limited the max. charging state to 4.15V per cell with options for even lower charging states.
Additionally it also tried to keep the batteries always under 35°C / 95°F and on average at 25°C / 77°F

Their newer Models limit the maximum charging Voltage to 4.1V and the float Voltage to 4.0V.
While already having a lower max charging state, they encurage Customers to only charge to 80% (~3.86V) and to discharge it to only 20% (~3.5V?)

Sources:
Tesla's impact report
Tesla's blog post
Tesla's Module Controller (pdf donwload)

As i rather find trustworthy sources and use them in combination to find my own opinion, i hope i can help other people with a similar mindset.

After reading all the articles and papers about our lovely Li-ion batteries, i will settle for the following settings for my 1st ever large battery bank.
Code:
3.97V maximum charge state - 3.95V release
3.3V minimum charge state - 3.45V release
40°C maximum use temperature - 2°C minimum use temperature

I will build a 14s32p battery, with ~2Ah per Cell. Resulting in a capcity of around 3.2kW/h. Applying those settings to it, will reduce the usable capacity to around 2kW/h but with a hopefully highly increased overall life cycle count.
 
Last edited:

Timbo

New member
Joined
Aug 7, 2021
Messages
8
Thanks, that is how I use my lithium batteries too. Keep at storage. Use between 80-40 Soc range. Only charge in what I need and discharge it back to storage before I'm done.

E.g. If I had a Tesla. I would predict the next day usage. Only charge enough to meet the usage and repeat for next day etc.
 
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