[F5506m]

It has been very cold in the east coast in the last few days, but the garage temperature has not fallen below 40's.

I have the i8 on the wall charger over the weekend, but once car reached 70% I shut of the power to the charger (Friday night) while still keeping the car connected assuming I will turn on the charger Sunday night to top up to 100% for Monday morning.

When I turned on the charger on Sunday night the batter charge had fallen from 70% to 13% and the car had not been moved! Anyone else experience this or what could have caused the battery drain. This has been my normal weekend practice if I do not need the car and have never lost charge level in the battery well not enough to ever notice.

[NGR]

Originally Posted by F5506m

It has been very cold in the east coast in the last few days, but the garage temperature has not fallen below 40's.

I have the i8 on the wall charger over the weekend, but once car reached 70% I shut of the power to the charger (Friday night) while still keeping the car connected assuming I will turn on the charger Sunday night to top up to 100% for Monday morning.

When I turned on the charger on Sunday night the batter charge had fallen from 70% to 13% and the car had not been moved! Anyone else experience this or what could have caused the battery drain. This has been my normal weekend practice if I do not need the car and have never lost charge level in the battery well not enough to ever notice.

I'm sure there are many potential faults but assume you've eliminated the obvious human error and haven't accidentally had it precondition itself a few times over the weekend when not plugged in?
I haven't noticed a drop on mine when left unplugged for days even in temps around freezing but I never plug it in and leave the the power switch 'off' though (basic laziness).

[F5506m]

Originally Posted by NGR

I'm sure there are many potential faults but assume you've eliminated the obvious human error and haven't accidentally had it precondition itself a few times over the weekend when not plugged in?
I haven't noticed a drop on mine when left unplugged for days even in temps around freezing but I never plug it in and leave the the power switch 'off' though (basic laziness).

I will unplug the car and see if there is any drop in battery charge. It is just annoying that you have to unlock the car to unplug the cord.

[fishpond]

Originally Posted by F5506m

I have the i8 on the wall charger over the weekend, but once car reached 70% I shut of the power to the charger (Friday night) while still keeping the car connected assuming I will turn on the charger Sunday night to top up to 100% for Monday morning.

Why shut the power off to the charger? I leave mine plugged in (with power to the charger) for days when I am away.

[F5506m]

Originally Posted by fishpond

Why shut the power off to the charger? I leave mine plugged in (with power to the charger) for days when I am away.

That is what I am doing now; I have been told keeping car at 100%/Charged all the time degrades battery life over time (probably an old wife's tale at this time.)

[fishpond]

Originally Posted by F5506m

That is what I am doing now; I have been told keeping car at 100%/Charged all the time degrades battery life over time (probably an old wife's tale at this time.)

BMW give an 8 year battery warranty here in the UK so even if there is some truth in that, it's not worth my time to worry about!

[F5506m]

Originally Posted by fishpond

BMW give an 8 year battery warranty here in the UK so even if there is some truth in that, it's not worth my time to worry about!

Agreed! just was annoyed this morning about the battery drain.

[i8Saffa]

I don’t know if anyone has had the same thing, but in the last 5 or 6 months I have been having the issue of charging my i8 overnight and then maybe day two later wanting to drive the car I have noticed that the battery has completely drained. It definitely did charge as I got notifications from the car when it started and stopped as well as my energy monitor shows the charge occurring.

Has anyone else experienced this? How is it at all possible the entire battery could drain itself when it has done nothing. Even checked that there is no scheduled preconditioning set.

[tommyb13662]

Originally Posted by F5506m

That is what I am doing now; I have been told keeping car at 100%/Charged all the time degrades battery life over time (probably an old wife's tale at this time.)

The battery itself never charges to true 100%. 7.1 kwh max yet only 5.2kwh used. The car does have a smart charger that shuts down power once it hits it's Max charge. Leaving it there won't degrade the battery much. My laptop is always plugged in rarely gets discharged and battery is still 90% after 3 years. The danger used to be before smart chargers. If batteries were left charging when full it would hurt them. But that's 10-15+ years ago now. If u use the electric to commute then keep it plugged in. You cause more wear recharging the tiny battery in sports mode. As this is a very rapid charge. I think in about 15min I saw it go from 1% to it's 70% max charge in sports mode. The wall charger is a very slow smart charger and can help improve battery life charging it that way.