Something to be concerned about? Seasonal? I'm not going downhill and the temp isn't warmer in 20 minutes
by snoogins355
Ford
Charged to 90% and goes up higher 1%-3% everytime. Why?
13 Comments
Mine does this as well, I’m in a bit of a colder climate in Canada I believe it’s because the battery warms up as it charges and then cools down in the morning when you get in. Percentage is calculated by voltage and voltage is affected by the weather
Battery percentage changes with temperature and it directly alters internal chemical reaction rates and resistance. The trucks software basically estimates remaining capacity rather than measuring it directly.
Mine does this as well. Usually a few mins after starting up. Will go from 90 to 91. I think it’s just the battery modules warming up ever so slightly. It’s REALLY hard to get a perfect SOC estimate when charging an NMC battery. When charging, 90% SOC is usually around 4.08V per cell. When discharging even under light load it will show somewhere around 4.0V per cell. Now, if that delta is smaller than expected the BMS will update the total SOC based on what it sees when the truck starts discharging.
Do you have it set to pre condition?
Cars use a nominal voltage lookup table to determine what percentage it is at.
The colder the climate, the lower your voltage reads also.
So if you charge cold and the temp goes up 10-30 degrees, you get a percentage swing l8ke this.
Its an engineering thing, not a software thing. No biggie
Normal. It’s called BMS Sway.
Cells and modules can have a variance between them.
When the BMS stops charging, it calibrates again.
Same here with my lightning. Weird cause my other car ev (Equinox) doesn’t have the same issue
This is normal, and happens because the temperature of the battery has changed since it was charged.
I see it happen “naturally” in spring and fall, when the overnight temperatures are a lot lower than the daytime temperatures. Around here (Atlanta), if you charge overnight but drive after dawn, temperatures will warm quickly as the sun rises. A warm battery can deliver more energy than a cold one, so the state of charge on the display goes up as the battery warms.
It can also happen in wintertime. If it is particularly cold when you charge and then when you warm the battery (either by preconditioning or just by driving) the state of charge will rise. It’s a bit funny (but totally normal) for you to start up at 90% state of charge and see it go up a couple of percentage points as you start driving around.
I noticed my truck did that today. I have daily charge limit set to 90%
This week I activated departure time as it’s starting to get chilly at night. The first couple days it was at 90% and showed 3.2kw power draw. This morning it was pulling 7.2kw and displayed 91% soc.
Mine does this as well. I charge to 90% and if it’s sorta warm it will usually creep up about 1% or so.
Cells just rebalance and recalibrate is all. A BMS isn’t going to be perfect.
That’s cause by the BMS balancing the pace, % is only an estimate
When it happens to me, I like to think it’s because I’m such a good driver, I’m getting a bonus percentage as a reward.