Battery Drain?

[DJinMD]

I'm a little over 3 months with my Mach E California Route 1. On Tuesday I'd charged my car's battery up to 100% in the garage I park in and unplugged the charging cable from the wall outlet. Hadn't touched or moved the car until this evening when noticed that the battery had gone down by 5%. In the 3 months I've had the car, this is maybe the 2nd time I've charged it to 100%, which is the only reason why I noticed there'd been a drop in charge percentage when I turned the car on. I do have a dash cam in the car, but it turns off 5 minutes after the car is turned off. Also the weather hasn't drastically changed where I am. Has this happened to anyone else?

Edit: meant went down by 5% not to 5%

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[BMT1071]

I'm a little over 3 months with my Mach E California Route 1. On Tuesday I'd charged my car's battery up to 100% in the garage I park in and unplugged the charging cable from the wall outlet. Hadn't touched or moved the car until this evening when noticed that the battery had gone down to 5%. In the 3 months I've had the car, this is maybe the 2nd time I've charged it to 100%, which is the only reason why I noticed there'd been a drop in charge percentage when I turned the car on. I do have a dash cam in the car, but it turns off 5 minutes after the car is turned off. Also the weather hasn't drastically changed where I am. Has this happened to anyone else?

I'm hoping you mean it went down by 5%, right??

 

[DJinMD]

I'm hoping you mean it went down by 5%, right??

I did. Thanks for letting me know. Made an update

 

[AKgrampy]

I'm a little over 3 months with my Mach E California Route 1. On Tuesday I'd charged my car's battery up to 100% in the garage I park in and unplugged the charging cable from the wall outlet. Hadn't touched or moved the car until this evening when noticed that the battery had gone down to 5%. In the 3 months I've had the car, this is maybe the 2nd time I've charged it to 100%, which is the only reason why I noticed there'd been a drop in charge percentage when I turned the car on. I do have a dash cam in the car, but it turns off 5 minutes after the car is turned off. Also the weather hasn't drastically changed where I am. Has this happened to anyone else?

Are you saying your car battery percentage dropped by 5% or are you monitoring your 12V battery and stating it dropped by 5%? Someone more knowledgeable will chime in I am sure but I believe if you have a phantom load and drain the 12V battery the HVB will maintain the LVB. Also might you have set a departure time and the car consumed the HVB preconditioning the cabin?

 

[DJinMD]

Are you saying your car battery percentage dropped by 5% or are you monitoring your 12V battery and stating it dropped by 5%? Someone more knowledgeable will chime in I am sure but I believe if you have a phantom load and drain the 12V battery the HVB will maintain the LVB. Also might you have set a departure time and the car consumed the HVB preconditioning the cabin?

Sorry, I meant to say that the car's battery percentage dropped by 5% from 100% to 95%.

I don't think I set a departure time, at least not knowingly. I also don't think I've started the car to a preconditioned cabin before. It usually maintains the same settings from my last drive

 

[Mach-Lee]

1. Are you talking about 12V battery or high voltage battery %?
2. How long ago was the last charge finished when you noticed it went down to 95%?
3. Is the car parked outside? Did the outside temperature change?

 

[DJinMD]

1. Are you talking about 12V battery or high voltage battery %?
2. How long ago was the last charge finished when you noticed it went down to 95%?
3. Is the car parked outside? Did the outside temperature change?

1. I believe it's the high voltage battery. I'm really bad at knowing the interworkings of cars, but in this case, it's the charge level indicator above the steering wheel that went from 100% to 95% without the car being used in a few days.

2. The last charge was finished on Tuesday morning. The car hadn't been used since then, until I drove it this evening and noticed the change.

3. The car is parked in a large garage. Although the temps did dip in my area, it wasn't by much. They went from the 80s to the 70s.

 

[Mach-Lee]

1. I believe it's the high voltage battery. I'm really bad at knowing the interworkings of cars, but in this case, it's the charge level indicator above the steering wheel that went from 100% to 95% without the car being used in a few days.

2. The last charge was finished on Tuesday morning. The car hadn't been used since then, until I drove it this evening and noticed the change.

3. The car is parked in a large garage. Although the temps did dip in my area, it wasn't by much. They went from the 80s to the 70s.

Thank you, it's normal that the battery would drain from 100% after sitting for 3.5 days. This is due to self discharge and cell balancing occurring. Self discharge is higher at high SoCs. Temperature change may also be part of it.

FYI it is not good for the battery to be sitting at 100% for very long because it degrades the cells. I would not leave it at 100% for more than one day. If plans change, you should drive the car to decrease the battery below 90% so it doesn't sit at 100% for days.

 

[DJinMD]

Thank you, it's normal that the battery would drain from 100% after sitting for 3.5 days. This is due to self discharge and cell balancing occurring. Self discharge is higher at high SoCs. Temperature change may also be part of it.

FYI it is not good for the battery to be sitting at 100% for very long because it degrades the cells. I would not leave it at 100% for more than one day. If plans change, you should drive the car to decrease the battery below 90% so it doesn't sit at 100% for days.

Ah, ok. Thanks! I'll make sure that it doesn't stay at 100% for too long next time

 

[HuntingPudel]

Yeah, as @Mach-Lee said, don't leave the HV battery at 100% ffor any period of time. Also, don't let it get below 10% for any period of time either. These batteries do not like to be near their State of Charge extremes (0% or 100%) for long periods of time and they will degrade if left at or near those extremes. It's fine to charge to 100% if you're leaving on a trip since you're going to drive it right away. Likewise, it's OK to drive it down below 10% if you are going to charge it right away. ??

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