disconecting battery

[badmoon]

Hi I need to disconnect my w211's main battery to check for draw down, is there any problem with this I need to be aware of, ie needing STAR to reset things or possible starting problems etc
Thanks

 

[AMGeed]

You may need to reset the windows and sunroof (if you have one) afterwards. Other than that, everything should be fine. No need for STAR.

 

[KillerHERTZ]

Just incase you didn't know this, always disconnect the negative 1st.

 

[tanuie]

Just incase you didn't know this, always disconnect the negative 1st.

Why would you all ways disconnect the negative first.

 

[badmoon]

Thanks for the advice. I have a current draw of 4.5a taking each fuse out drops it down to 0.25a but then it always goes back to 4.5 once I put it back in. I,ve tried each fuse in all 3 fuse boxes. When I took the 1st out I thought I had struck lucky, no such luck. I'm completely stumped now.:fail

 

[Benzmanc]

Why would you all ways disconnect the negative first.

Just in case the tool you're using accidentally touched the body. Earth off first and reconnect last.

 

[KillerHERTZ]

Why would you all ways disconnect the negative first.

Safety. The current is flowing from the battery from the Live.

If you disconnect the Live you could potentially create an arc should you be holding/touching a tool, the cars body or anything else metal.

The basics of car electronics

 

[whitenemesis]

Safety. The current is flowing back to the battery from the Live.

If you disconnect the Live you could potentially create an arc should you be holding/touching a tool, the cars body or anything else metal.

The basics of car electronics

Yup, bridge the positive to the body with the spanner and you could weld it solid ...

Don't ask how I know

 

[renault12ts]

Yup, bridge the positive to the body with the spanner and you could weld it solid ...

Don't ask how I know

How do you know?

 

[whitenemesis]

How do you know?

It took a sharp smack with a hammer to free it...

 

[Major774]

Running a voltage drop test across the fuses is best, pulling fuses may wake something up and you are back to the start.

You leave the battery as it is, let the car rest. Then measure for millivolts across each fuse, it should read '0' if not then you have something using current on that fuse.

 

[badmoon]

Thanks Major774 i shall try that over the weekend