[gameson]

i read through google and youtube that BMW recommends trickle charge your car battery from the engine bay (front)

I live in an apartment where if i do it from the front, i may risk getting the charger stolen.

if i do it in the rear, i can place the charger in the trunk and just run wire from trunk to outside, so it protects the charger.

but is it OK to trickle charge battery from the trunk?

Thanks.

[Billfitz]

The battery doesn't care. The main advantage to using the charging posts is access, which is considerably easier than direct to the battery. BMW does state that either the battery post or charging post is OK.

[atzebmw]

Better not...

[Billfitz]

Who are you going to believe? BMW, or BMW? There being three different battery types is why chargers can selects between Lead Acid, AGM and Lithium Ion.

[tjlees]

I have the same problem.

I charge from the charging post but put the charger and extension lead in the car with leads coming out of back of the bonnet near wipers and back into car.

alternatively optimate solar (duo if lithium) with solar panel on the dash and similar arrangement for leads out of bonnet. brilliant if you have no power socket. the 20w panel is fine for trickle or 40w if you want to recharge from near flat.

you can charge from the rear lighter socket in boot, but sometimes it shuts off the socket so not reliable enough for me.

BTW charge directly charging battery confuses the battery management system as prev said, so not recommended.

[xxxjecxxx2]

Secure trunk against closing with towel.

Disconnect both battery terminals in trunk.
Hook up trickle charger direction to battery.

[Amina2511]

Originally Posted by xxxjecxxx2

Secure trunk against closing with towel.

Disconnect both battery terminals in trunk.
Hook up trickle charger direction to battery.

A few people told me to do that also .disconnect terminals and charge battery directly .not the using the hood method ..

[Billfitz]

How many of those people are electrical engineers?

[NealfromNZ]

If using the rear make sure that the battery external vent is still in place and hasn’t been removed by a previous owner or servicing company when running an acid battery.

Otherwise you have a the potential of an battery gas explosion with some battery chargers that spark when connected.

Usual procedure should also be used to connect charging terminals first before turning on charger

Here’s a guideline, although much of this doesn’t apply as your not taking the battery out to bench charge.

https://www.safework.sa.gov.au/workp...acid-batteries

[Billfitz]

We don't have lead acid batteries. Ours are AGM, which allows them to be inside the car rather than under the hood.

[NealfromNZ]

Have a look at the function of the venting valve on AGM batteries. Still a risk and they have gone up.