Battery percentage increase then decrease.

[EVJoe]

So on Tuesday I left my house at 85%, got to work at 68% (pretty normal for winter), then I left for lunch and turned on the heat about 10 mins before I left, when I got out on the road, I noticed that the battery percentage was now at 70%. I thought no way it could be correct but ignored it. I got back to work at 62%, then turned on the heat 10 mins before leaving again and drove home. When I got home the battery was at 40%. I plugged in and it is supposed to start charging at 11PM, but it started charging right away at 4:15pm. I got in the car and turned it on and the battery percentage was now at 32% so I let it charge. Wed it was back to 85% and preheated no issues Wed. This morning, I went out to the car and it did not charge (don't know why, might be my home charger) or preheat so I left the house at 44%. On my way in there was a pop up saying, "system failure cannot determine range” Or something like that, it went away pretty quickly. No warning lights nothing. I got to work at 27% and plugged in here and its currently charging at least. Any ideas on what could be going on? I hope I don't have a battery failure starting.

Sponsored

 

[Mach1E]

It’s only an estimate.

Sounds like the difference between a warm battery and a cold one.

Totally normal.

 

[TEVOT]

So on Tuesday I left my house at 85%, got to work at 68% (pretty normal for winter), then I left for lunch and turned on the heat about 10 mins before I left, when I got out on the road, I noticed that the battery percentage was now at 70%. I thought no way it could be correct but ignored it. I got back to work at 62%, then turned on the heat 10 mins before leaving again and drove home. When I got home the battery was at 40%. I plugged in and it is supposed to start charging at 11PM, but it started charging right away at 4:15pm. I got in the car and turned it on and the battery percentage was now at 32% so I let it charge. Wed it was back to 85% and preheated no issues Wed. This morning, I went out to the car and it did not charge (don't know why, might be my home charger) or preheat so I left the house at 44%. On my way in there was a pop up saying, "system failure cannot determine range” Or something like that, it went away pretty quickly. No warning lights nothing. I got to work at 27% and plugged in here and its currently charging at least. Any ideas on what could be going on? I hope I don't have a battery failure starting.

Same thing here. I charged last night to 92%. Took it off the charger last night and drove to Walmart (about 0.8 mile) went from 92% to 89%. Got back home and was at 85%. Got up this Morning was back at 89%. Drove to work (1.8 miles) now at 86%.

 

[allenj444]

The percentage is only an estimate. It’s the difference between a cold battery that shows less, and a warm battery the shows more. Average the two to get a general idea of how much battery you have but keep in mind it’s not totally accurate. In the Summer months when the battery is warmer you will get a better and more stable idea of the percentage of battery remaining.

 

[noway]

If battery heats up the percentage goes down, when cooling the battery the percentage goes up. This is because it will estimate a higher total energy output with higher battery temperature. Not sure what actually happens, but it is very noticeable when having a 6+ kW charger and turning on battery heating. It will consumed 6+kW, the heater and everything else uses less than 6kW, but percentage on battery goes down while actually charging the battery

Sponsored