Earth Leak

[tuscan_thunder]

I suspect my car has an earth leak.

Battery doesn't stay charged for long - few days max. When it's running I'm getting 14v across the battery so it's charging from the alternator.

Where would the most likely places for an earth leak be? I imagine it'll be a nightmare to track down.

[Northernpar]

Could be a draw on the battery or it could be a defective cell in the battery itself. When the car is turned off have you measured the current draw from the battery? Another option is to take it into a suitable garage for a battery discharge test/SG check of the electrolyte.

[Shug]

I'd be tempted to think dead cell in the battery as well - they don't half take a kicking in an Elise. Stick a meter on it and find out if anything's pulling current though...

[Stewart]

Your brake light switch isn't knackered leaving the lights blazing even when not braking/driving

[robin]

An earth leak is a completely different type of fault. Earth leakage is a problem with mains appliances where they leak some current back through the Earth wire instead of the Neutral. Modern houses will pop the "fuse" on the main when this is detected beyond a certain level.

On a car, there is no such issue - the "earth" is supposed to carry all the return current.

Most probable fault is that the battery is dead. Brake light switch popping on when parked is also common in S1 (not heard of it in S2, but assume that the switch/pedal is the same, so the issue could still occur).

You can work out whether it's the battery or the wiring by isolating the battery when not driving the car. I.e. when you park up, disconnect the EARTH cable from the battery, having first disarmed the alarm (basically, you loosen the cable clamp, disarm the alarm, then pop the cable off).

If the battery still goes flat overnight/over a couple of days, then the battery is gubbed. If the battery stays good while disconnected, then you have a wiring/switch fault somewhere (or you have a tracker!!).

Cheers,
Robin

P.S. Cars do suffer from "bad earths" which causes the disco light effects on the rear light clusters when the indicators are on, but these won't cause any battery drain.

[tuscan_thunder]

Battery is less than a year old and the cells seem healthy. I have a C-Tech charger/conditioner and it tells you if there is a duff cell or battery related issue: it has done with other batteries but is not showing on this one. The 'eye' thing on the battery seems to be showing that all is well.

I will test the current draw when everything is off. Have tried leaving it with the battery disarmed but that had not changed anything.

The lights behave themselves and are not sticking.

I think a current draw is likely: when the charger is on, and has been left on for 14hours solid at 14.4v (don't know the current feed), it still will not reach full charge.

If it is something drawing current and it's not the alarm, what's likely? Radio? Immobiliser?

[robin]

What car is it? S1/S2 etc.

When you say you've tried it with the "battery disarmed" do you mean the "battery disconnected" or the "alarm disarmed".

I really think you should try it with the battery disconnected ... when it still goes flat you'll know it's a duff cell ... when it doesn't, you'll know it's something else.

Likely candidates are the brake lights (which you've eliminated), the radio if it's not the OEM fit (wired in wrong, it could perhaps drain the battery), tracker if fitted is most likely IMHO.

Anything plugged into the cigarette lighter or extra stuff wired in (extra lights, extra amplifiers, etc.)?

The basic wiring is very simply and beyond leaving your lights on, there isn't an obvious way to drain the battery.

As it happens, I am very skeptical of battery conditioners ... if you're going to leave the car for a prolonged period, leave the -ve terminal of the battery disconnected instead - that's how they store batteries in the first place!

Cheers,
Robin

[robin]

BTW, your C-tech charger thingmy is probably only producing a couple of Amps or less, so 14hours ain't much into a couple of 100Ah battery ... the best way to charge the battery is off the alternator - if it isn't charged after a couple of hours running, it never will be (or your alternator is goosed).

Cheers,
Robin

[renmure]

Your brake light switch isn't knackered leaving the lights blazing even when not braking/driving

Now there is a bit of a coincidence.. thats exactly what happened to my exige over the past week in the garage. Well and truely discharged the battery

[tuscan_thunder]

What car is it? S1/S2 etc.

When you say you've tried it with the "battery disarmed" do you mean the "battery disconnected" or the "alarm disarmed".

I really think you should try it with the battery disconnected ... when it still goes flat you'll know it's a duff cell ... when it doesn't, you'll know it's something else.

Likely candidates are the brake lights (which you've eliminated), the radio if it's not the OEM fit (wired in wrong, it could perhaps drain the battery), tracker if fitted is most likely IMHO.

Anything plugged into the cigarette lighter or extra stuff wired in (extra lights, extra amplifiers, etc.)?

The basic wiring is very simply and beyond leaving your lights on, there isn't an obvious way to drain the battery.

As it happens, I am very skeptical of battery conditioners ... if you're going to leave the car for a prolonged period, leave the -ve terminal of the battery disconnected instead - that's how they store batteries in the first place!

Cheers,
Robin

S1.

I meant alarm disarmed, not battery.

I will try it with the battery disconnected. The radio has been in since I got the car (4years+) and I have nothing else electrical added to it.

I'll try the battery off and see how it goes. The alternator is, I'm pretty sure, charging.

I will see how I get on and report

(The C-Tech can lift 2 tractor batteries in series from totally flat to full in 24 hours so it should be capable of putting out a fair kick)

[vet111s]

Have just been searching for similar problems to mine-battery flat after about 10d without use (less in the winter). Apparently my car does have a tracker fitted which would explain the drain however trying to find a way of keeping the battery conditioned without having to disconnect it.
Tried this last year
http://www.solarkitsdirect.co.uk/produc ... ry=related
(the 135 version) but the battery still died! Could the tracker be draining more power than it's providing?
Have ordered this
http://www.solarkitsdirect.co.uk/product.asp?P_ID=241
but looks like the halfrauds 063 battery won't have the required 50Ah rating to avoid overcharging and consequently I'd need a charge controller (more money!)
The car is parked in a drive so no mains for a normal trickle charger.
Sorry for the ramble but any advice would be much appreciated

cheers folks
Ali

[tut]

I have had the problem for years now on N1, but Craig has not been able to trace it. When it began with starting problems, he took a long earth cable from the battery, through the car, and onto the engine lug. That sorted out the starting problem. However the slow drain continued, and I have no radio, tracker or even alarm. Seemed to be worse when the keys were left in which pointed to the ignition barrel, but again not able to trace it to that.

She has been laid up for two years now, and the battery went completely, so we fitted a new one a few weeks ago. Put her in the garage but left the keys in, and in two days the battery was drained to the no glimmer state. Have the Ctek on now but will disconnect the neg lead.

tut

[mckeann]

Do you have a battery cut off switch, ala race car cut off??

[vet111s]

I certainly don't have a battery cut of switch fitted!

[r10crw]

The thing that makes tuts car strange was that the draw was intermittent. Sometimes it would last a week and the next time only two days, Ive had every fuse out to try and eliminate circuits but still couldnt trace the fault, trouble with n1 is the wiring, because of the honda nothings quite standard.