locked Re: Batteries starting to get weak - MMM - What to do -

Arno Luijten

Hi Joerg,

Actually these cars do not charge to 100% on daily basis. Other then Tesla you are not allowed the top 5 percent of the charge meaning you can only charge to 95%. Typically Supercharging only goes to 80% to preserve the batteries. Tesla advises to not use the top 10-20% of  the capacity for daily commuting and keep the SOC between 20 and 80%. Off topic : there is some data available that suggests that extensive supercharging affects battery life so that explains the advise of Tesla. Battery warranty is only for 70 or 80% of the capacity so if you loose 19% of the capacity it is on you.

Also cars use a different chemistry (Li-ion instead of LiFePO4)  and are not kept at 100% SOC for extended periods of time. Lithium does not like to be KEPT (as in days or weeks) at 100% but if you start draining shortly after charge the impact is not so great.
The use case for cars is very different from boats. Most people don't stay in their car when not driving, so everything is switched off. No so for a boat. So a car can sit without charging for some time but on your boat (when in use) you are constantly draining the batteries.


Arno Luijten
SV Luna,

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