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The mkiv Supra Owners Club

Battery/Starting Problems


Pilchard

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Before I start I'm going to admit now that I'm not that mechanically minded, especially with car electrics, the advice Ive found has been on here and to be honest I don't know exactly what I'm looking for. The first part of the problem may have nothing to do with my current problem but im going to include it anyway. Also I apologise for a long winded story.

 

Bought the car back in Nov 14, the previous owner had stored the car in his garage and it had been stood months after the MOT with no use on a trickle charger. Picked the car up fine, started all ok and got it home to my mates garage for safe storage until the bodyshop could underseal it.

 

Two weeks later came to pick the car up and it wouldnt start (completey dead, no lights etc.), jumped it, drove it to the bodyshop where they said it was doing the same all week while it was there. Picked the car up took it out for a run, used it like you would any new car and no problems for about 3 weeks.

 

Took it for a full check over, got the alternator tested at the specialist which were fine but it was still having the same problem when stood for long periods of time. Decided to get this checked out at auto electrician when I got the car back home but then as I was using the car mostly through show season it seemed to fix itself, had no problems for about 6 months.

 

Sorned the car at the end of Oct 15. Started the car two weeks later to check everything was ok, dead again. The voltage was about 9 volts, car would start fine on the jump leads. as soon as you took them off it wouldnt. Multiple volt readings suggested it was the battery.

 

Fitted a new battery about 6 weeks ago, started it every two weeks, was fine and thought id fixed the problem until last weekend. The cars ignition is fine but as you turn the key it makes a ticking noise. All doors, alarm etc work. Volts read 11.2, lost about a volt in two weeks which doesn't suggest the battery is been drained.

 

I dont understand how the car cant start with 11.2 volts, theres enough power for everything else. Jumping the car now and leaving it a few days it just does the same thing.

 

Looking into this, could it be the starter motor? And are the two things related from problem previously fitting the new battery? Going to clean the battery terminals and try to find the starter to have a look. Could it be anything else?

 

Thanks

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I'd say there is nothing wrong with your car - you are just leaving it too long between starting it. Your alarm will be slowly draining your battery over time. I doubt mine would start if i left it for 2weeks either. 11.2v on a battery might as well be 0v, a healthy charged battery should see ~ 12.8v.

You need to take the car for a decent run to charge that battery back up to full, starting it and then turning it back off a minute later will just flatten the battery more in the long run, hence your new one being dead now too.

If you plan on leaving it for any extended periods without a run then you should disconnect the battery completely or use a trickle charger.

Edited by Marty (see edit history)
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I'd say there is nothing wrong with your car - you are just leaving it too long between starting it. Your alarm will be slowly draining your battery over time. I doubt mine would start if i left it for 2weeks either. 11.2v on a battery might as well be 0v, a healthy charged battery should see ~ 12.8v.

You need to take the car for a decent run to charge that battery back up to full, starting it and then turning it back off a minute later will just flatten the battery more in the long run, hence your new one being dead now too.

If you plan on leaving it for any extended periods without a run then you should disconnect the battery completely or use a trickle charger.

 

100% all of that.

 

The exact same thing was happening with mine - left it a few months without turning it over and the battery went flat due in a large part to the alarm running it down.

 

Disconnect your battery if leaving it sat a while.

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100% all of that.

 

The exact same thing was happening with mine - left it a few months without turning it over and the battery went flat due in a large part to the alarm running it down.

 

Disconnect your battery if leaving it sat a while.

 

That does make sense as it was fine for 6 months when i were using it every week, its just ive had cars before that start on a much lower voltage and least attempt to start when the battery is dying. Supra known for this?

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I'd say there is nothing wrong with your car - you are just leaving it too long between starting it. Your alarm will be slowly draining your battery over time. I doubt mine would start if i left it for 2weeks either. 11.2v on a battery might as well be 0v, a healthy charged battery should see ~ 12.8v.

You need to take the car for a decent run to charge that battery back up to full, starting it and then turning it back off a minute later will just flatten the battery more in the long run, hence your new one being dead now too.

If you plan on leaving it for any extended periods without a run then you should disconnect the battery completely or use a trickle charger.

 

 

I agree with this completely. I get just over 2 weeks on mine without charge and as I don't use it from month to month nowadays it used to drive me mad, as said its the alarm normally. My missus has a na with no alarm connected currently and that can stand for much longer and starts on the button. Toolstation do a brilliant little trickle charger for peanuts: http://www.toolstation.com/shop/p17423 I use this now and have done for a while, its been great so far.

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Can only echo the above, however the only thing that I disagree with is a two week battery life?! My old na sat for a few months in winter and still started first turn of the key. My tt has been sat for a couple of weeks with only moving it a few feet out the garage and no battery issues.

 

I thought the same, it came with a fancy alarm, which I dont know half the features of, which could explain the quick draining. Thanks for all the advice, going unsorn it in the new year and start using it like I should, battery is on charge at the moment and il go from there.

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Can only echo the above, however the only thing that I disagree with is a two week battery life?! My old na sat for a few months in winter and still started first turn of the key. My tt has been sat for a couple of weeks with only moving it a few feet out the garage and no battery issues.

Really depnds on what type of immobiliser and alarm system you have fitted. Some seem to draw much more than others. The one in my old NA was a cobra and that was fine, the one in my current TT is a Autowatch and seems to draw quite a bit by comparison. My old Merc daily is ok for around 3 weeks before it becomes an issue.

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If the battery is definitely good and all connections are good, then something worth bearing in mind are the solenoid contacts in the starter motor. These can cause intermittent starting problems. Kits are available to replace these for a tenner or so.

 

As for alarm drain, I know mine draws around 50mA - including the clock and stereo memory etc. This equates to around one eightieth of the battery being drained per day. If you then had a battery that wasn't 100% (pretty much any battery that isn't brand new), then it would only be a matter of a few weeks before the car wouldn't start - less than that if it's particularly cold.

 

I put my battery on an Optimate trickle charger every couple of weeks just to keep it topped up. It can be left on all the time and mine often is.

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Thanks for all advice again, tried it again this morning, battery read 11 volts, lost .2 from yesterday, wouldnt start, jumped it, read 12.5, left it running for 20 mins and started it up again and its fine. Just needs a good trickle charger, as I think mines broke and a good run out in the car to keep the volts up

 

SteveC - I did think this from what ive read on here about the starter motor, im going to keep an eye on it and after its been used regulary, see what happens. Least there cheap fixes if it is that.

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If you can test the current drain whilst the car is not running with the alarm on and off, then that'll give you a better idea of what's going on. If you can't do this yourself, then any electrician should be able to check this with a multi-meter in a matter of a few minutes.

 

As I said, mine draws around 50mA with the alarm on. My alarm is a Clifford with quite a few sensors, so it possibly takes a little more current than a more basic alarm.

 

Some time ago I found two trackers concealed in the car. They were also drawing current, which didn't help. You could also have a tracker hidden away somewhere.

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Thanks for all advice again, tried it again this morning, battery read 11 volts, lost .2 from yesterday, wouldnt start, jumped it, read 12.5, left it running for 20 mins and started it up again and its fine. Just needs a good trickle charger, as I think mines broke and a good run out in the car to keep the volts up

 

SteveC - I did think this from what ive read on here about the starter motor, im going to keep an eye on it and after its been used regulary, see what happens. Least there cheap fixes if it is that.

 

You're only seeing 12.5v from the battery terminals with the car running? That's not right. With the alternator spinning over, you should be about 14.4v. A healthy battery should be between 13-13.5v with no load on it & the motor not running.

 

Sounds to me like you've got a battery with a few dead cells and an alternator that's not charging it properly.

 

I'd expect to see about a month out of a decent battery if you've got the alarm on there & maybe radio memory to keep.

 

Get someone to check the current draw on the battery with the key off / interior lights off etc.

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