BMW i8 Dead Battery and i8 Not Charging..... Fixed!

[@kingjeffishere]

Thanks for sharing!

[@Djpaul-lo1px]

Any I8 owner that didn’t even know it had a 12 volt battery deserves it to go flat.

[@hussilveridico3002]

Great Car

[@Gadne92.5]

Hi Fred. The User Manual for i8 states that IF the "auxiliary battery" (12 volt one) goes flat, you should plug the your "travel charger" / "home charger" to the car and wait. Eventually it *should* wake up and began to charge the High Voltage battery pack and then the 12 volt one. This may take up to 1-2-3 hours or so before there's any "life" in the car. This is greatly affected if you're having USA type 110V or "mainland European" 220V household socket, among other variables. May I ask how long did you wait until you contacted BMW? Btw. the 12V battery is charged / maintained via the HV battery pack, there's no ordinary alternator in i8. If you want to prolong the life of the 12V battery, keep the car plugged into your home charger. Only when plugged in, the system will maintain the 12V battery. Greetings from fellow i8 owner. Mine 12V battery went flat after car sat unused for 5 weeks, it was 3 month old dealer installed BMW branded battery. It "came to alive" via the procedure I described earlier 🤓

[@tribble10]

Hey Buddy! Thanks for your comment and tips. I had left my car unused and uncharged for 3-4 weeks when this happened. I called BMW to ask to speak to a technician and they gave me no pointers apart from the battery price and calling out BMW Assist which would have incurred a call out fee. I then left the car plugged into the BMW supplied 240V home charger for 2 days hoping it would spring back to life but no luck. (The green power indicator led was lit on the charger but no blue charging indicator lit over the 2 days). It seems that if the 12V battery is dead, the in-car computer will not allow communication with the charger to allow current to flow to start charging of the High Voltage Battery which in turn charges the 12v battery. You would have thought BMW would have allowed a "Dumb" direct charge to the 12V battery via the main charge cable for situations like this..... Of course now having experienced this issue I leave it on charge 24-7! I was thinking of the disaster it would have been had I left it at an airport for 3-4 weeks whilst on holiday :(

[@Gadne92.5]

@@tribble10 Thanks for insight!

[@kingjeffishere]

I appreciate that info. I currently always recharge every time I take it out. But, this is a good to know!

[@777smuki]

Thanks for sharing

[@chriswood4174]

Did you find the cause of what made the battery go flat in the first place, it just happened to mine today, I haven't used the car for 4 weeks and the battery is completely dead

[@tribble10]

@chriswood4174 no that's exactly what happened with mine, not used for around 4 weeks and then completely dead. I now have the charger plugged in all the time just in case it happens again because it's parked in my garage and I don't have the clearance to open the doors fully enough to open the bonnet

[@MatthewRSimpson]

I have a 2014 i8. Isn't it funny that we have to make videos to say 'if you have a flat battery, then charge it up'. This is something i have done since i passed my test in 1988. We tend to miss the most simplest of explanations for issues as cars get more technical. Years ago you would never have dreamt of phoning the dealers because you had a flat battery after several weeks of not using the car. Granted, you also wouldn't have expected the battery to go flat either of course.

[@manasdas9461]

Bmw i8 is my dream car . I'm gonna buy a pre owned one .. can you tell me if bmw still take these in for full servicing? And if the pre owned car's batteries are dead (the main batteries) how much it would cost approximately

[@tribble10]

Hi, yes BMW does offer full servicing on these vehicles for the foreseeable future.(Was recently quoted £700 for full service from BMW) Replacement batteries from BMW approx £8000 if all 6 cells need replacing (approx £900 per cell Plus labour costs). I have read its much cheaper to buy OEM compatible batteries (approx 400 Euros per cell) and ask a specialist to fit. BMW have an 8 year or 100K mile warranty on the original battery so keep an eye on the year of the car you plan to buy!

[@bangals32]

Had the same problem. Discovered if the doors are unlocked with a flat battery, there’s no way of locking the vehicle even with the manual key…BMW Customer services was a joke and had no answer apart from sending a flatbed to come and pick up the vehicle and bring it to the garage. Managed to open the bonnet and I did jumpstart the car. Drove to Bmw and got the battery changed however they insisted on doing a diagnostic which cost me another £175 😠

[@AbdulHadi-zr5yv]

which model year is your I8

[@bangals32]

2019

[@karanmody2899]

I have the same problem - what 12v charger do you use?

[@tribble10]

@@karanmody2899 any standard 12v car charger will do

[@CindyWilliams-yx3wl]

How did you get the terminals odd. I can’t seem to lift it off.

[@tribble10]

I think there are 2 small 10mm bolts on each terminal that need to be loosened and the terminals will then just lift straight up

[@CindyWilliams-yx3wl]

They don’t seem to lift up. Also can I just take off the positive one?

[@tribble10]

@CindyWilliams-yx3wl yes you can, I only removed the +ve terminal and it may be a bit stiff ( try prying up with insulated screwdriver)

[@CindyWilliams-yx3wl]

@@tribble10 what about a tool for lifting it up? I’m afraid to do damage

[@tribble10]

@@CindyWilliams-yx3wl just an insulated flathead screwdriver will do. Make sure you loosen the retaining bolt on the terminals first!