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UMC overcharging

minsup23

Member
Feb 22, 2016
100
29
Chicago, IL
I have a gen 1 UMC to charge my model 3 at home. I set it 60 or 70% and when the car has to charge at least 10%, it always charges an extra 2%. I use the gen 2 work on a standard outlet. Any idea why the car charges an extra 2%?
 

earthwormjim

Member
Jun 25, 2019
167
179
California
Last edited:

ZOMGVTEK

Member
May 19, 2015
559
442
'Merica
The car does this for some reason. I suspect it’s some sort of predictive algorithm that determines how much to overcharge to ensure you have the set charge the next day. It appears to change from time to time for whatever reason, sometimes my car is stops right at the limit, other times it charges a percent or two past. Sometimes it will use that extra percent or two by the next morning since the car can stay awake for hours after charging in some situations. Either way, it’s not too big of a deal. Based on all available evidence, the battery is more likely to have an internal failure that renders it useless before the degradation is bad enough to warrant replacement charging to even 80-90%.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
4,269
Buford, GA
Why? Based on studies of the cathodes in high nickel content lithium batteries, it's possibly harmful to charge higher over time. Model 3 batteries probably have cathode nickel ratios greater than 0.8.

https://pubs.acs.org/doi/full/10.1021/acsenergylett.9b00733

Is there any difference in line input voltage between the places you charge at, @minsup23?
Read the many threads of people who charge to 70% and below all the time and the apparent degradation that they get.

And sure, there's a LOT of difference in line voltages between charging locations. That's expected, 100+ to 400++.
 

earthwormjim

Member
Jun 25, 2019
167
179
California
Read the many threads of people who charge to 70% and below all the time and the apparent degradation that they get.

For Model 3's or Model S/X? Model S/X are supposed to have nickel cathodes at or below 0.8 ratios, so charging above 60% is inconsequential according to that study.

The BMS not balancing the cells, which is what you're referring to, is not degradation either, degradation is a chemical and mechanical process.
Balance issues can be solved with the occasional deep discharge, full charge cycle.
Actual degradation can never be fixed.

And sure, there's a LOT of difference in line voltages between charging locations. That's expected, 100+ to 400++.

You misunderstood my question on voltage, it wasn't directed at you.

I was asking the OP about line voltage they use at the two locations they charge at, perhaps if there is a correlation between "overcharging" past their set limit and what line voltage is used, that might explain a possible cause.
 

ngogas

Active Member
Sep 19, 2018
1,725
1,191
Utah
Elon said to charge to 90% and plug in Tesla is a happy Tesla. So I’d go with that. The rest of these replies are bs and are just guesses from non Tesla workers/designers. Lol.
 
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