Disconnecting the battery

[poleonpom]

Hi all,

I've not yet had to disconnect the battery to do any work on my P38, but the time has come. I need to do some welding on the exhaust, so I'd like to know that when I disconnect the battery what will happen? - does the system reset itself? Does the alarm become an issue? Should I just leave it all to itself and go and have a beer instead?;)

[p38arover]

No problem. I disconnect mine whenever I need to.

All you'll need to do on reconnection is to ensure your key is not in the car if the doors and windows are closed. The car will lock itself.

After that, simply retune the radio to lock in your stations and then go through the window and sunroof setting procedure.

There are a lot of scaremongers out there but it really isn't a drama.

[rovercare]

No problem. I disconnect mine whenever I need to.

All you'll need to do on reconnection is to ensure your key is not in the car if the doors and windows are closed. The car will lock itself.

After that, simply retune the radio to lock in your stations and then go through the window and sunroof setting procedure.

There are a lot of scaremongers out there but it really isn't a drama.

Yep, no stress, I've disconnected mine a few times, just usual stuff, radio code, windows and sunroof need to be set

I even welded my exhaust without disconnecting, I've never disconnected on my own, but always on customers cars:D

[Hoges]

What sort of welding? I'm told electric welding is "iffy" without 'disconnecting' the becm...whatever "disconnecting" means. I'd always thought that oxy welding would be a better =safer bet on a vehicle with multiple ECUs. Thoughts?

[Blknight.aus]

ALWAYS wind down the window prior to disconnecting the battery, IF its going to stay disconnected for a while get a wheely bin garbage bag, place that over the top of the window frame and then close the door.

[poleonpom]

What sort of welding? I'm told electric welding is "iffy" without 'disconnecting' the becm...whatever "disconnecting" means. I'd always thought that oxy welding would be a better =safer bet on a vehicle with multiple ECUs. Thoughts?

Arc welding - as that's what I have. I'm looking to repair the exhaust system as the pipe has corroded to the rear box, so I thought I'd drop the rear box and run a pipe straight out as there's not much difference in the noise factor (surprisingly).

That brings up a thought, even after disconnecting the battery, should Ii also physically disconnect the Becm? thoughts please

[Blknight.aus]

It cant hurt to... theres also no harm in dropping of the engine and trans ECU's as well as minimising the risks of damage by earth clamping on the piece of work as near as practicable to the weld AND in the case of rubber mounted exhausts on the engine side of the weld.

[rovercare]

Arc welding - as that's what I have. I'm looking to repair the exhaust system as the pipe has corroded to the rear box, so I thought I'd drop the rear box and run a pipe straight out as there's not much difference in the noise factor (surprisingly).

That brings up a thought, even after disconnecting the battery, should Ii also physically disconnect the Becm? thoughts please

Yes, best take off the door skins and unplug the door modules aswell, maybe unplug the EAS compressor and brake pump, unplug the instrument cluster, also the hevac unit.......

Just weld the exhaust already:D