battery died AGAIN, wtf!!...

Post Wed Feb 20, 2013 9:45 pm

Went to the gym, on the way their my headlights kept turning off and on. Got to the gym and knew something wasn't right, the dash lights seemed dim.

turned it off, hit the weights. Came back, turned the key and it tryed to turn over but there wasn't enough charge to turn it over. Tryed again but nothing.

Ive changed the battery and alternator recently.

Post Wed Feb 20, 2013 10:18 pm

You've checked that the alternator drive belt is OK and correctly tensioned, I assume?

Also, check the engine-to-body earth strap is in good order.

Post Wed Feb 20, 2013 10:28 pm

just went back, charged the battery for 20mins. It fired up first time, then went to switch the headlights on and it made a sound like a it shorted and then the engine cut off.

So im assuming it has something to do with the headlights, i drove home with just side lights on with no probs

Post Wed Feb 20, 2013 10:30 pm

U changed your wheels again? :lol:

Did you get a second hand one? Get a volt meter and check for consistent 14.4 volts,

The only thing you need to refurb your alternator is the voltage pack two screws on the side of it put a new one in and it will be good as new,

Check your coolant pipe isn't leaking I had that issue it was leaking on the alternator and playing bout with it

Post Wed Feb 20, 2013 10:53 pm

bmw9818 wrote:U changed your wheels again?

Did you get a second hand one? Get a volt meter and check for consistent 14.4 volts,

The only thing you need to refurb your alternator is the voltage pack two screws on the side of it put a new one in and it will be good as new,

Check your coolant pipe isn't leaking I had that issue it was leaking on the alternator and playing bout with it

LOOOOLLL You wanker!! if im ever in croydon remind me to pop round n give u a slap lol

It must have something to do with the headlights as it cut straight off when i switched them on as if it shorted... is that possible?

Post Wed Feb 20, 2013 10:55 pm

i got a second hand one about 2 months back had it checked at halfords and everything was fine

Post Wed Feb 20, 2013 10:58 pm

kangman wrote:i got a second hand one about 2 months back had it checked at halfords and everything was fine

Halfords fitters

First place I would be looking is engine earth as already mentioned.

Post Wed Feb 20, 2013 11:06 pm

kangman wrote:It must have something to do with the headlights as it cut straight off when i switched them on as if it shorted... is that possible?

If there is indeed a short, then that could cause problems - unusual, but check the wiring to them anyway.

Post Thu Feb 21, 2013 12:05 am

kangman wrote:
bmw9818 wrote:U changed your wheels again?

Did you get a second hand one? Get a volt meter and check for consistent 14.4 volts,

The only thing you need to refurb your alternator is the voltage pack two screws on the side of it put a new one in and it will be good as new,

Check your coolant pipe isn't leaking I had that issue it was leaking on the alternator and playing bout with it
LOOOOLLL You ******!! if im ever in croydon remind me to pop round n give u a slap lol

It must have something to do with the headlights as it cut straight off when i switched them on as if it shorted... is that possible?

Will do!

Btw halfords ain't the best place to get shit done.. Mainstream garages tend to be full of underpaid staff working towards targets where quality isn't priority

Post Thu Feb 21, 2013 5:42 am

kangman wrote: It must have something to do with the headlights as it cut straight off when i switched them on as if it shorted... is that possible?

Not quite, Sherlock. Headlights run on electricity, so anything in the charging system could be at fault here. If a battery is empty, 20 mins of charge will do f-all - maybe just enough to spin the starter once. If you've started the engine and you're not charging, then your battery is now dead, or running on vapours. At this point, switching on the headlights would be the last kick in the nuts for the battery, and the whole engine will die.

You need to check you're getting 13.8V at idle, and that each electrical connection in the Charge circuit is tight and rust-free. If you're not getting 13.8V, replace the belt and the alternator.

http://www.e30zone.net/e30zonewiki/index.php/Charging

Post Thu Feb 21, 2013 9:56 am

Switching on the headlamps on something as well and carefully designed as a BMW cannot cause a 'short'! BMWs were designed by German engineers, not French or Italian accountants or artists!
The headlamp circuit is permanently live right up to the headlamp relays, and the fuses that protect the headlamp circuits are located less than 2cm away - very little chance for a 'short'. The whole of the headlamp control circuits are 'earth to operate', so the worst that could happen with a fault here is for the lights to turn themselves on.
As Grrrmachine says, turning the lights on is just the straw that breaks the camels back.