AMGangster

Lads,

I just bought a new battery. I've been told that there is a procedure to replace this to keep the computer happy. Can anyone shed some light on this for me?

Also, will I need to reprogram the Eurocharged tune?

Thanks!

Donny

abcut973

Well if there is a specific procedure i would be glad to know as well.
Last time I swapped my OEM for a braille lightweight one I just disconnected the negative pole and wait a little while for any static electricity. Then disconnected the positive and remove the whole thing.
So far so good.

otakki

Maybe keeping a battery tender/minder on the clamps will maintain charge in the system while the battery is out.

-Marlin-

About a month ago this was discussed. I posted a vid where it was recommended that 12volts be maintained to power the car electronics while the battery is disconnected. It was left open ended whether this was necessary.

I was hoping an MB tech could chime in and let us know what the dealership procedure is.

It's a shame we can't get a tech manual for these cars.

AMGangster

I searched the forum looking for a previous post, but returned nothing. If anyone knows for certain I would appreciate it. Or, I will roll the dice.

rickclass

I recall that video too, the just of it is that you need to hook up the terminals to a batter charger temporarily as you swap out the battery...keeping constant power to the ECU....

andrew c230k

Think you guys are really over reacting, even with my ocd and pride in doing the job right all you do is take the old battery out and put the new one in, I didn't notice any difference in any settings in the car when the battery was out and disconnected.

jcfay

the video may have only applied to older model MBs, then. But he recommended maintaining voltage the entire time, as all settings would be lost otherwise. Perhaps MB and maybe even other manufacturers figured out that this would be unreasonable considering the batt needs to be replaced every 3-5 years or so...

Ingenieur

I'm not sure I would swap batteries out with voltage applied to the system, ie, 'hot'

Easy to do though
Battery tender on the under hood jumper posts
Or one that plugs into the lighter socket

andrew c230k

With the battery out my alarm still managed to go off so there must be some residual power left even when the battery is removed.

Ingenieur

I think the alarm system has it's own small battery

AMGangster

I've always been one to swap and go, but my mechanic last time mentioned this procedure to me. I don't know if he would just drumming up business. I am changing it Sunday and will let you know if it blows up!

-Marlin-

Good point. That's helpful. I'm thinking the same thing as Ingenieur.

Ingenieur

If the battery is disconnected where would residual power be stored?
A motor winding down and acting as a generator?
Capacitors?

8o8is

The only procedure to follow when disconnecting is to remove the ground first then the positive cable. Installation is the reverse, positive on first, then the negative. It won't affect your ECM/ECU's, probably only your clock and radio presets.

AMGangster

I did exactly this and had no issues. Took all of 10 mins to change it out.