Battery going flat, suggestions ?
Discussion
Keep going to my 944 after a week, for a well earned weekend blast (weather permitting) and it is flat as a pancake, it is only a week, the battery was a new Bosch one in February. It starts quickly with a jump and once it is going it will restart but I want to avoid doing that as a routine.
It lives outside and its under a cover at the moment, as far as I am aware I am not leaving anything on but something must be draining the battery.
Any suggestions, was thinking a trickle charger but it beign outside would mean some convoluted cabling.
It lives outside and its under a cover at the moment, as far as I am aware I am not leaving anything on but something must be draining the battery.
Any suggestions, was thinking a trickle charger but it beign outside would mean some convoluted cabling.
Something must be sucking it dry, mine lives in the garage and often isn't used for three or four weeks with four weeks being about the maximum it can sit around without the batter needing a charge. Because it is generally used with in this time, I don't bother with a trickle charger.
Remove the earth lead from the battery's earth connector, then put a multimeter set to "current" - start with it set at 1A - between the lead and the earth connector on the battery. If no current is registered then reduce the setting to lower values - 500mA then 250mA for example - until you see something.
You should expect to see around 5mA to 10mA, which would maintain the clock and possibly the ECU and/or central locking as appropriate/if fitted.
Any more than 10mA will be a problem - time to start pulling fuses one by one until the current passing through the meter reduces to 5mA or 10mA (or even to zero, possibly). The last fuse you pull that made the current drop is the one for the faulty circuit(s) (assuming the car isn't riddled with faulty circuits and electrical devices
) 
.
You should expect to see around 5mA to 10mA, which would maintain the clock and possibly the ECU and/or central locking as appropriate/if fitted.
Any more than 10mA will be a problem - time to start pulling fuses one by one until the current passing through the meter reduces to 5mA or 10mA (or even to zero, possibly). The last fuse you pull that made the current drop is the one for the faulty circuit(s) (assuming the car isn't riddled with faulty circuits and electrical devices
) .It could be a lamp remaining on such as under bonnet or glovebox, I use my mobile on video to check if a lamp is staying on.
If you measure current on the battery you could see 50mA or so depending on what alarm system is being used. It is also likely the battery will need replacing as once run down very low they start to cause issues, you may be lucky though.
To see if the alternator is working you should see 13.5 - 14.5 volts across the battery terminals with the engine running.
If you measure current on the battery you could see 50mA or so depending on what alarm system is being used. It is also likely the battery will need replacing as once run down very low they start to cause issues, you may be lucky though.
To see if the alternator is working you should see 13.5 - 14.5 volts across the battery terminals with the engine running.
.. Mine does this regularly, 17 days it will go for from full charge to won't turn over, alarm/immobiliser is 1 thing, add a tracker drain on top. and about 2 weeks is what you get, I only use mine 2 or 3 times a week tho', the rest of the time it has a solar trickle charger on it thro' the cigarette lighter, this puts some juice back in, but not enough to counteract the drain.. maybe every day use keeps it topped up better.
Every Porsche I've ever had does this, it's part of the joy of ownership..!
Every Porsche I've ever had does this, it's part of the joy of ownership..!
My old 944S would flatten the battery after between a week and fortnight of non use, turned out that the alarm was the problem, fitted a trickle charger to cure problem. On 944s common problems could be glovebox light staying on and also rear hatch light staying on, poor front door switches can also lead to the interior light staying on. No problems on the 911 with upto about 4 weeks without flattening the battery
mollytherocker said:
If you dont drive it often, then the only way forward is a battery charger/conditioner. It does sound like you have a 'leakage' but it wont matter if its on life support.
I use a Draper one on my 993 and its perfect.
Wot, the charger or the 993?...I use a Draper one on my 993 and its perfect.
Hi Peter - how's baby girl doing?
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