Officially Weirded Out! Dead Electrics

[Mr H]

So ....... Moved the car to wash it; all fine. Went to start to move back to parking spot and absolutely nothing electrically; no noises/clicks, no dash lights etc. Tried with different "master" key and the same; tried with the "other" key, the same. Arrgggh. Checked with a cheap voltmeter, 11.8v at battery and at charging points under bonnet. Swore a bit (lot), kicked the (metaphoric) cat and tried again with original key - started fine! Only difference was I didn't have the key to my son's VW Polo in my pocket this time? Checked voltage again but with engine running, this time 13.7v. Any ideas?

btw, the DAB function on the aftermarket Kenwood (fitted by previous owner) now works whereas before it wouldn't. Definitely a weird day!!

 

[IanA]

I used to get this a lot on my 2.8 when I had a battery isolator. I removed that and went to town on the battery terminals- job done.
BTW, the charging points under the bonnet only test the 300A supply cable to the starter. There's a 200A supply cable from the battery to the fuse box as well. I had that corrode to oxide under the driver's seat on my 2.0.

 

[Mr H]

I used to get this a lot on my 2.8 when I had a battery isolator. I removed that and went to town on the battery terminals- job done.
BTW, the charging points under the bonnet only test the 300A supply cable to the starter. There's a 200A supply cable from the battery to the fuse box as well. I had that corrode to oxide under the driver's seat on my 2.0.

Cheers. Battery terminals look good and are tight; the battery is not an original! I'll try and have a look at the 200A cable once it stops raining (and is daylight).

 

[jaguartvr]

I get this quite often, give both battery terminals a good yank and all is well again.
My battery is good, the terminals look good and are clean but every now and again they need a hard wiggle. Drives me mad and it's not on just one Z3, the BMW battery terminals are crap.

 

[t-tony]

The terminals aren’t crap it’s the way they’re cleaned, tightened and maintained where the problems arise. How many Z3s are there and how many with bad terminals.

Tony.

 

[colb]

The positive cable connection on the battery passes through a pyro link that fires if the vehicle detrects an accident so it isolates the battery. Worth checking the connection to this is in tight and providing a solid connection, have seen instances of a loose connection here causing problems.

 

[jaguartvr]

I have 5 Z3's on the drive, 2 are a pain, 2 are dodgy and one is ok. I have also had problems with E46 battery cables. Normal battery terminals with a nut and bolt running through them give no problems at all, why needlessly complicate things?