Flat battery

[Geoff Crispin]

Just went to go out in the Z after not using for about 3 weeks and battery totally flat. This also happened a few weeks ago but thought that it was due to lack of use and testing/checkin/unlocking and locking doors but no.
Casually speaking to a Z owner from Porlock in a Minehead carpark weeks ago he was having the same problem and had paid out for it to be sorted, electrician found (?) the problem rectified it, but weeks later problem still there.
has anyone got any suggestions as to where to look, I am still waiting for the computer diagnostic disc and cable to come from my nephew which might or might not direct me to the area.

Thanks?

 

[GazHyde]

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.

 

[jonco]

It is not unusual for a battery to `idle drain' after 3 weeks, particularly if it is not in top condition to start with. If you have a short from your previously mentioned lock problems this will add to idle drain rate.

 

[Geoff Crispin]

Thanks chaps, the battery was new when I purchased the car, might be looking at remote this Sat if my nephew comes down from Surrey, but I should be able to check the boot light.
Will let you know.
After battery charged up in 45mins I went out and went/ran as normal will have to use it more which was not my original intention as it is a 2nd/3rd car and used for trips out.

 

[jonco]

............ as normal will have to use it more which was not my original intention as it is a 2nd/3rd car and used for trips out.

Either that or invest in a battery conditioning charger of those idle periods.

 

[hard top]

When we had an unusual pile of snow over here, around seven or so years ago, I left the car standing for four weeks.
Yep, dead battery and that knocked my alarm out, that might have happened to yours before you bought it? @Geoff Crispin.
My battery was brand new too and re-charged no problem but still no alarm.

 

[andyglym]

I keep mine on a CTEK trickle charge system if I'm not using it for a few weeks. Very good system.

 

[t-tony]

My Z3 does it too after 4/5 weeks but more regular use and it's perfect!

Tony.

 

[Redline]

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 permenantly 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?

 

[Geoff Crispin]

Thanks again for all the advice chaps, I have never had this sort of problem on any other cars and some were large ie 24valve 6 cly.3Ltr Senator, Humber imperial 3Ltr straight 6 etc. and kept outside,where as the Z is tucked up in the warm garage with the TR4 to keep it company, the battery goes flat on that through lack of use but usually over a longer period.
Electrice are not my strong point, but my nephew might be coming down on Saturdat to see if he can sort out the remote/alarm for me but not confirmen.

 

[5harp3y]

Something might be draining the battery too much when idle.

Alarm
Stereo (really common on cars not just Z3)
Boot light as suggested.

 

[Redline]

The general consensus is 5mA parasitic current draw when everything is off.
In addition to the above, bad earth connection, faulty door switch (leaving the alarm system and window system still operative awaiting inputs).

 

[jonco]

.................I'd expect most cars to take 50mA or more just doing their alarm duty and other electronics that are permenantly 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?

The following text is a Mike Fishwick comment on a.net thread a few years ago and ties in with your comment @Redline

"The 'Everything off' current for a Z3, like most cars, is about 50 mA, due to leakage through the alternator diodes, keeping memories alive in the radio and engine ECU etc.

This works out at 8.4 ampere-hours per week, or 33.6 per month - which may be your entire battery capacity. Remember that for a lead-acid battery capacity at 0 C is about 50% of whatver it has at 20 C, so a cold winter, with plenty use of the headlamps etc will son show up any problems withthe battery - or the charging system."

 

[Kevlaar]

had this problem with mine.flat battery after around 3 weeks.i now put it in the garage and dont lock it and seems to be ok now.think maybe central locking draining the battery.has stood for around five weeks when i last started it and it started fine.

 

[Synclare]

I've left mine for a few weeks untouched (locked manually, no alarm) and still starts fine. Could be a back feed through alternator diodes as Mike F suggests. Try connecting an ammeter in series to measure the current drain.

 

[Tracy Dee]

My battery was flat yesterday when I tried starting it for work very slow then clicked it was last used on the 20th on Stacey's event which was great.
I knew it would not be used over Xmas period so purposely never set the alarm just locked the door with the key still flat .
We had a spare battery out in garage which we keep charged for emergency put it on today started right up.
It's an old battery of unknown province so may need a visit to euro car parts if this one dies fingers crossed but not confident.

 

[Geoff Crispin]

Thanks a lot of more helpful info. I kept car locked over Christmas period (as usual) in the garage as we were away and I also have a cut out system on the TR4 which I use when away just encase, better to be safe than sorry. So if I cant find the cause/fault I will either give it a run or put it on charge which is very straight forward.

 

[Eddie Zedder]

As a couple of zedders have already mentioned, if you can, leave it unalarmed so that it reduces battery drain. I run mine up to temperature every couple of weeks to keep the battery topped up. This also keeps the cylinder bores and other bits lubricated. An added bonus is that I also get to here those six cylinders purring and that exhaust note while I am waiting for spring.

 

[hard top]

What's the difference in height above sea level, and are they land locked or by the sea, also is it a built upmarket or very open?

We are between 4 & 6 meters below see level and up there they are only slightly higher, they have sea to the north and border Germany to the east and yes, it is very open and they are saying tonight, with the wind, it is -10c. The only part of the Netherlands that has 'hills' is the south, on the border with Belgium, and a quick plug, that is where the Dutch cruise is this year, temp down there today was 7c.

 

[t-tony]

As a couple of zedders have already mentioned, if you can, leave it unalarmed so that it reduces battery drain. I run mine up to temperature every couple of weeks to keep the battery topped up. This also keeps the cylinder bores and other bits lubricated. An added bonus is that I also get to here those six cylinders purring and that exhaust note while I am waiting for spring.

You shouldn't be doing that Bryan, the god that is Mike Fishwick will tell you you're only filling you cat with water and you will rot your exhaust out from the inside.

Tony.

ps. That's what I would do too. But I know F--- all,.............................. apparently.