Gaddammit now what!!?! The Z just drained a brand new battery in 12 hours :no:

 

I've always had a small current which results in the battery not being able to start the car if I leave it undriven for 5 or 6 days, but after a normal drive to work it's been fine. Been like this for years.

 

However after being left stood for a mere 4 days over the weekend, she started ok on Monday morning (a little sluggish to start but that's to be expected), fired up and got me to work no problems - handing a 350Z it's own arse in the process ;)

 

Anyway on the way back yesterday evening I noticed that the voltage (on my Apexi turbo timer unit) was lower than normal. Normally it will show 14.2v at the start of driving, and level out to 13.7ish after a few minutes. However it never got above 13.6 and dropped to as little as 13.3 - I wasn't using lights and I even took my stereo facia out I was that concerned.

 

Thinking the battery was starting to fail, or the alternator had packed in, I managed to get it home no problems. Passed a voltometer across the battery and got 12v. Luckily I keep one on standby (this one measured 13.6 volts) so I swapped them over, smeared a bit of Vaseline over the terminals, hooked them up and she was ok (didn't take her for a drive). Locked her up as normal.

 

Following morning, she wouldn't even start (barely 10v in the battery), so took the standby car to work. First thing I did when I got back this evening was to put a multimeter across the battery and she's losing 25A somewhere!!! :eek:

 

I started with the fuses in the engine bay behind the steering wheel, and when I remove the 30A IGN / SKID fuse the current immediately drops to 0.6A.

 

I've not had time to look at any other fuses, I've left the positive off and put her on maintenance charge until I can get to the bottom of it.

 

Can anyone suggest the next course of action - is it worth putting the IGN / SKID fuse back in and continuing with the footwell fuses, or is this as far as I can get? If so where would I start looking next?

interesting development - I decided to take her out to fill up with petrol [holy crap its been off the road for 3 months during which time we've both been sulking and ignoring eachother lol] - took her off maintenance, started her up and eased her out of the driveway. got to the petrol station with no probs. after starting her up again it turned over a dozen times before firing up which is a first, but no probs after that. [i put this down to the car not having been run for so long]

 

anyways as the voltage seemed to be fairly stable at 13.6ish I decided to warm her up a bit and go for a gentle blast. waiting at some lights I noticed the rear windows were demisting by themselves. I'd not turned them on, and the light on the pod was off.

 

I pressed the button, it beeped, and the voltage jumped about 0.2-0.3v to 13.8/13.9. Pressed again and it dropped back down to 13.6v. No light came on on the button when up until now it's always come on when pressed (I've got the blue/red LED pod conversion)

 

Got her back onto the driveway and decided to leave her off charge to see what happens overnight. The following day - 13v in the battery. The day after, a little under 13v. The day after, about 12.5v!!! With the above problem it would have died overnight to the point that the doors wouldn't unlock themselves!

 

So it seems that somehow there's been a failure at some point between the demister button and the element (or whatever you call it!) but while it's been standing on the drive the window has not been demisting. Can anyone think of any possible cause?

 

To try and prove this point I'm going to leave her on charge tomorrow night to make sure the battery is full, then take off charge, press the demister again and see if the battery dies the night after that.

hi,

 

i know probably sounds too simple but have you tested the battey. It may have the ability to take the charge but not have the ability to "hold" the charge - alternator would be working as normal but over a period of time following a run would discharge itself - You could try disconnecting the negative lead and leave for a few days and if battery is flat then there is nothing pulling amperage. I know for a correct test following a run or charging a battery should be left for several hours before being tested - sorry if i have misread anything

Are little things like the horn and demister all wired together in some way? It's starting to sound that perhaps there is a problem with a current or ex accessory that's been spliced unbeknown into the wrong place or wiring is loose/unprotected?

A plug in the engine bay wouldn't affect the horn or demister surely? Maybe take the under cowling off at the driver side and inspect any wiring including into the kick panel. It's all very random so far, so maybe something not quite right in the wiring in that area. It's aright checking fuses, but the problem is not that things don't work, they're working too much! :)

 

Ah well, there's my thoughts, happy hunting :detective: hope you find the culprit that's causing it.

this is a post to give you ideas and hope, not answers sadly (and maybe you already have the answer. Lets hope) but if your earth and alternator and regulator are not working as they should the current in you car will take any route it can to make a circuit-so will send you round the houses giving you false hope/readings in many places then suddenly appear fixed... one minute the lights might seem to help matters(creating a circuit) then next moment they might be a hinderance (draining current), all due to a see-saw on/off intermitent action of one or all of the above three.

dont give up hope... but maybe give up some cash.. :0

It would be interesting to see a meter in series as you activate the switch for the de-mister,

just to see if it reacts every time you depress it.

Also, Maybe a relay problem, randomly sticking?

With the meter showing the problem when the switch is in the off position, try pulling the relevant relay to see if the drain drops.

Faulty electric rad/AC fan/ switch ? theres not much on a zed that will draw that sort of current .. and as redwine has said, i'd pull random relays while you have the multimeter in series

theres a trick you can do by using the alternating current setting on the multimeter what ever the reading is shows what your powerdrain is, or osmething along those lines sorry i cant be more specfic