Flat battery

[Geoff Crispin]

Bulb has already been taken out,. \never used it in the dark.
Charger is now saying fully charged, will see in the morning.

 

[Geoff Crispin]

It all seems normal the right lights on charger and trickle charger are on, so it was the boot light

 

[Geoff Crispin]

Having left the car for a few days with the trickle charger on it started first time today and took it for a 50/60mile round trip this afternoon and all went well.

 

[t-tony]

They don't like being left alone mate, they get mardy and won't go when you want them to!

Tony.

 

[Geoff Crispin]

My Z is not on its own its got the TR4 for company HaHa

 

[l3ggy]

I've discovered that my flat battery issue is due the door switch jamming and putting the interior light on even when the door is closed.

 

[Geoff Crispin]

Glad your sorted, switches seem to be a problem on these Zs

 

[pgunter]

A little circuit cleaner and then some gt85 should sort it out.

 

[Geoff Crispin]

Thanks HT

 

[Stevenod]

Most cars will sink some current out of the battery all the time. Usually it's fine for a couple of weeks, but after that it is sufficient to discharge the battery, especially if the battery is old and/or it gets cold overnight. That slow discharge can also build up salts on one of the plates. This also can impact it's useful life. Charging it reverses this process.
Don't know the capacity of the Zeds battery but assume is 75Ahrs. Big though they are it's a finite capacity. I'd expect most cars to take 50mA or more just doing their alarm duty and other electronics that are permanantly powered (door locks, clocks etc). You should get 6 weeks potentially. That's in perfect conditions. 3 weeks is all I would expect tops to be honest - anything more is upside.

Anybody done a current check on an car?

Just bought a new, beefy battery for my new Z3 as it would go flat after a week or so despite looking suspiciously new.

Thought I'd do a current check.... 3,850mA discharge, and a spark when connecting up in case I needed a further clue.

So 3.85A on a 12.6V battery is about 50W. Presumably not chafed wiring as a fuse would have gone.

I'm about to run a fly-lead from the battery to the fuse box so I can have my ammeter by the fuses as I pull them one by one until the discharge stops. Would appreciate the team's suggestions though. That sort of power is lights-on territory, not radio or alarm etc. Anyone seen similar faults?

I'll start with the electric seats, as the driver side height adjust... doesn't, and the power mirrors on the same hunch; LHS doesn't adjust.
The boot-light bulb has been removed already, probably by the previous owner who couldn't find the fault and threw a cheap battery on and sold it on to me- doh!

 

[Jam03]

Have you checked the loom of doom? Mirror not adjusting also sounds suspicious. Cigarette lighter might be worth checking too.

 

[Stevenod]

Have you checked the loom of doom? Mirror not adjusting also sounds suspicious. Cigarette lighter might be worth checking too.

Sounds interesting. What, pray, is the Loom of Doom. Presumable pronounced with Gandalf accent?

 

[Jam03]

Sounds interesting. What, pray, is the Loom of Doom. Presumable pronounced with Gandalf accent?

Search loom of doom on here and you will find advice. It’s the wiring loom that goes to the boot lid. Common place for wires to break and cause a short.

 

[Stevenod]

Hmmm. I pulled every fuse and every relay (I think. Car's new to me.) and while No 35 was drawing 7mA none made any difference to the 3 and a bit amps.
Need to leave it for now. I'll look up loom of doom; thanks for the tip.
Ah, just saw your post above. Thanks again.
Wilco.

 

[IanA]

When an electric motor moves something (seats, mirrors, windows) when the end of the travel is reached, you'd expect the power to be cut. Sometimes it doesn't so the trick is to get the item to the end of its travel and then just tweak it back in the opposite direction. Then when you release the switch, you know that the power has been cut successfully.
My drivers seat did that once- about a 10A draw though.

 

[bear2020]

The light in the boot has been known to stay on when closed. Easiest way to check is to put a camera phone recording video in the boot, and close it.

Exactly what mine was took the bulb out never had the issue since

 

[Kate and rod]

We disconnect our battery and that works

 

[Duncodin]

When an electric motor moves something (seats, mirrors, windows) when the end of the travel is reached, you'd expect the power to be cut. Sometimes it doesn't so the trick is to get the item to the end of its travel and then just tweak it back in the opposite direction. Then when you release the switch, you know that the power has been cut successfully.
My drivers seat did that once- about a 10A draw though.

I had that with the passenger seat. I'm 6ft and not often the passenger. But I'd rolled the seat all the way back. Next morning totally dead battery. I thought it was duff so bought a new one. Size of the spark when connecting up the new battery told me there was a big drain.

I think the seat can cut power when it reaches the end stop. But if the seat is reclined just a bit that stops it reaching the stop.

In my case it was the switch sruck in the back position. Weak rerurn spring.