[olap]

How to charge battery in E90?
Two connection points are placed next to engine. They should be used for starting of other car or own car and they are also mentioned in manual as connection points for charging (?!?).

What is not so clear for me whether I can directly connect charger to car terminals which are next to engine or I should disconect battery and connect charger directly on standalone battery.


Question 1:
is it not somehaw dangerous to use charger (e.g. impulse charger) and destroy car electronics (BC, radio, other electronics) if battery is connected ?? (because other manufacturers explicitely prohibit that - before charging you have to unplug battery from car ! )

Question 2:
if I disconnect battery from the car, then some special initialization procedure will be needed, when I connect battery back - code for radio, radio stations, alarm, BC settings ... ??

Thank you in advance for your answers

[techkeith]

Yes, use the points under the hood to charge, thats the same place we use if we are programing a car. Do not jump the car from the battery, I have heard that if you try to jump a car from the battery, there is a possiblity you could blow the bst, the airbag on you battery to disconet the starter and jump point in case of an accident so no big sparks near fuel, but i have yet to see it. Now if you are using a trickle charger I dont think it would do much for the battery through all those cables from the front of the car to the back, so if you are useing a trickle charger connect it to the battery, with the battery still connected, do not use the one for the cigeret lighter, that circuit is turned off after about 15 minutes. You are right if you disconet the battery you will have to do some initilizations, that you would need our scan tool for, depending on how long it is diconected you may need to initilize the sterring angle sensor, or if you have active steering you need to go through the set up for that, but as for windows and sunroof you can do that on your own. I have never heard of someone damaging the elctrical componets with the battery connected, the battery acts as a kind of shock absorber for the vehicle electrical system as it is, it absorbs any spikes from the alternator. Well I know this is somewhat long and confusing, but I hope it helps. Have a good one man.

how exactly do you disconnect the battery? you just have to disconnect the negative right?

[HyperM3]

I keep my m3 on a charger through the winter via the points under the hood. Should work the same on the e90.

[wuufer001]

just curious and a dumb question, but can a battery be charged by another car if it's taken off from the car?