unknown constant elec. drain

[micktheshed]

My Terrano has always had this problem but after 5 years and a new battery I've finally decided to ask everyone on here for help.
Despite a new Bosh battery & the Terrano being inside a locked garage with the key in place, so no alarm set & no Known item on to cause the drain, the battery still drops from 12.6 to 12.1 or less inside a week. Inside 2 weeks the voltage is down to 11.5-11.7! At this level the car struggles to start, & sometimes doesn't!!!! In the winter it's even worse so I've resorted to trical-charging the battery every 5-7 days (or disconnecting the battery altogether!).
I'm at a loss as to where to look though I vaguely remember this problem being mention, on here, some years ago. Perhaps it's a 'normal' thing on Terranos but it has never happened on any previous car, except due to a faulty battery, & I'm talking 50+ years here!
Over to those with more Terrano-years than me then......... LOL.

 

[Terrano Steve]

You can measure parasitic drain by removing one battery terminal & using a multi meter across terminal & battery post.
Now remove one fuse at a time until you see parasitic drain stops this will be the circuit causing the problem.

 

[macabethiel]

Battery Drain

Quite a few possible causes, Terrano Steve has made a good starting point for testing with a Multi-meter if you have one.

I assume you have done the obvious things like removing bulbs from interior lights, glove box & footwell lights if you have them etc. Other things might include the Radio if it is not the original one and has station memory or signal amplifier faults if radio works without key in Aux or Ign On positions.

I would look at having the Alternator checked out as the rectifier pack can drain and also be passing some slight AC current. Others here might be able to tell you how to do this yourself.

My old r3mR used to drain the battery if not used most days even in the Summer. After replacing the battery it eventually came up with a dim red battery light fault on the dash. Local mechanic removed the alternator and the problem lay in the rectifier pack. It had been replaced by a previous owner but with a standard unit for a Terrano 2.7 alternator, not the high output unit fitted in the r3mR. He sourced the correct amp rated rectifier and it was sorted.

 

[micktheshed]

You can measure parasitic drain by removing one battery terminal & using a multi meter across terminal & battery post.
Now remove one fuse at a time until you see parasitic drain stops this will be the circuit causing the problem.

Welcome advice, shouled have thought of that myself LOL; I will give it the once-over tomorrow.
Just had a thought, dashboard LCD is on all the time could this be the problem?

 

[macabethiel]

Welcome advice, shouled have thought of that myself LOL; I will give it the once-over tomorrow.
Just had a thought, dashboard LCD is on all the time could this be the problem?

Not sure them staying on is normal but current drain on LCD would be very small I would have thought. On my Merc the LCD bit is only on when engine is running and when you first open the door. It goes out with the interior lights on the timer if you do not start the engine after a few minutes.

 

[jims-terrano]

Didn't you mention that you leave the keys in the ignition whilst it's locked in your garage?
Will the LCD switch off when the keys are removed?

 

[rustic]

The radio takes power all of the time to maintain the memory, if an after market one has been fitted, then this might be 100 mA to 200mA.:doh
Then there's the ECU and the alarm system, which both take power just sitting there.
Then there is leakage, if you have a power feed to a towing socket, this can have a leakage of a few mA. Equally a dirty battery top can leak a few mA as can any electrical contact.
If we leave our Mav for say three weeks whilst on holiday, I now disconnect the battery, as I don't like leaving a charger on 24/7, in the meantime I use an intelligent charger when the vehicle stands for more than a few days.
As the saying goes, use it or loose it. If used daily for a decent run of say 10 or more miles, then the battery will always be fully charged.
However... if it takes a great effort to start each time from cold, maybe because of faulty glow plugs, or if the alternator isn't charging that well, maybe due to a slipping belt, then the battery will run down.

If the voltage on your battery is showing 12.1volts having rested, then it only has a charge of 50% this is not good for a battery, and a voltage below this will suffer rapid sulphation, and will have permanant damage. In fact it is better to maintain these batteries with at least 80% charge all of the time for a long life.
This state of charge chart might help.

 

[Terrano Steve]

Quite a few possible causes, Terrano Steve has made a good starting point for testing with a Multi-meter if you have one.

I assume you have done the obvious things like removing bulbs from interior lights, glove box & footwell lights if you have them etc. Other things might include the Radio if it is not the original one and has station memory or signal amplifier faults if radio works without key in Aux or Ign On positions.

I would look at having the Alternator checked out as the rectifier pack can drain and also be passing some slight AC current. Others here might be able to tell you how to do this yourself.

My old r3mR used to drain the battery if not used most days even in the Summer. After replacing the battery it eventually came up with a dim red battery light fault on the dash. Local mechanic removed the alternator and the problem lay in the rectifier pack. It had been replaced by a previous owner but with a standard unit for a Terrano 2.7 alternator, not the high output unit fitted in the r3mR. He sourced the correct amp rated rectifier and it was sorted.

That's a good example when a diode packs up in the rectifier the battery light often glows very dim but alternator is still charging, so battery is draining when the engine is off.

 

[jims-terrano]

Just carrying on from Rustics post. The grey 12s socket has a permanent live which just happens to be the bottom pin. I've seen this short ever so slightly to earth causing a drain too after the socket has filled with water.

 

[zippy656]

The ashtray has a light in it too, but I can't remember if it comes on with side lights or when pulled open,

 

[micktheshed]

Didn't you mention that you leave the keys in the ignition whilst it's locked in your garage?
Will the LCD switch off when the keys are removed?

Dashboard LCD display stays on ALL THE TIME that battery is connected. The ONLY time it is off is when there is no power. Only car I've ever had that has a permanent display. No wonder it is relatively short lived before trouble sets in LOL.

 

[micktheshed]

The ashtray has a light in it too, but I can't remember if it comes on with side lights or when pulled open,

Had me worried there for a moment but mine deff. hasn't got an ashtry light.

 

[micktheshed]

Rustic seems to have covered the most likely power losses. Since they could all apply to mine looks like I'm stuck with it, short of using the car more often or disconnecting the battery LOL.
It might explain why the original owner, who only covered 300 miles per annum (yes that's three hundred!) for most of his 5 year ownership, got through 2 replacement batteries!
I now make a point of using the Tera, or trickle-charging the battery, once a week min., especially during the winter, but it looks like this is not really enough. Going by my wife's 2003 Astra (deff. still on it's original battery!) which gives no trouble but is used most days.
As has already been said: "use it or loose it"!

Thanks for all your replies.

 

[rayf3262]

Dashboard LCD display stays on ALL THE TIME that battery is connected. The ONLY time it is off is when there is no power. Only car I've ever had that has a permanent display. No wonder it is relatively short lived before trouble sets in LOL.

It would appear that it is normal for the LCD to dislay trip meter, odometer, and clock at all times.
When the ignition is switched on the only change on the LCD is that it now displays the temperature as well.

 

[jims-terrano]

I liked the advice given earlier about using a multimeter to measure current draw and start removing each fuse until the drain drops.

Also has anyone fitted any after market power sockets or wiring of some sort perhaps?

 

[macabethiel]

The radio takes power all of the time to maintain the memory, if an after market one has been fitted, then this might be 100 mA to 200mA.:doh
Then there's the ECU and the alarm system, which both take power just sitting there.
Then there is leakage, if you have a power feed to a towing socket, this can have a leakage of a few mA. Equally a dirty battery top can leak a few mA as can any electrical contact.
If we leave our Mav for say three weeks whilst on holiday, I now disconnect the battery, as I don't like leaving a charger on 24/7, in the meantime I use an intelligent charger when the vehicle stands for more than a few days.
As the saying goes, use it or loose it. If used daily for a decent run of say 10 or more miles, then the battery will always be fully charged.
However... if it takes a great effort to start each time from cold, maybe because of faulty glow plugs, or if the alternator isn't charging that well, maybe due to a slipping belt, then the battery will run down.

If the voltage on your battery is showing 12.1volts having rested, then it only has a charge of 50% this is not good for a battery, and a voltage below this will suffer rapid sulphation, and will have permanant damage. In fact it is better to maintain these batteries with at least 80% charge all of the time for a long life.
This state of charge chart might help.

That's a great chart Uncle Rustic my Jeep this morning showed 11.2 volts so the battery is on charge with my Ctek as we speak. I put it down to the cold and short journey work....might be the battery on it's way out.

 

[rustic]

Let's do some basic maths, you have parasitic drain of say 100mA, so that's 0.1 Amp so over a day, 0.1 x 24 = 2.4 Ah per day
So 2.4 x 7 = 16.8 Ah per week which is approx 20% of an 85 Ah battery.
No wonder your car won't start if you leave it at the airport for say two weeks, ie 40% discharged...
Leave it for a month, and you have discharged approx 70 Ah in just 4 weeks, thus you have a flat battery.

So adjust the maths if your drain in more or less, so easy to see why your battery looses charge.
A battery also has a natural discharge, and if in good condition could become flat within a year anyway, without anything connected. Temperature plays an important part in this rate of discharge.

Hope it helps,
Rustic

 

[solarman216]

Rustic is spot as usual except that a battery will start to sulphate in as little as 3 months not connected, a refresh charge should be applied at not much more than monthly intervals, incidentally I cannot say for later motors but my 98s both make a sound if you have the key in and open the door, and as it is not always heard by me I sometimes forget and leave it in, overnight this is not a problem but over a weekend if I have not used it come Monday it is distinctly slow, so key in = something is powered, Rick

 

[Mobieus_uk]

I don't think that maths works like that as the voltage will be dropping as well and ohms law shows that if voltage drops and the current draw is the same the amps will increase so you wouldn't have a linear drop but a exponential drop so it will get flatter quicker

 

[solarman216]

I don't think that maths works like that as the voltage will be dropping as well and ohms law shows that if voltage drops and the current draw is the same the amps will increase so you wouldn't have a linear drop but a exponential drop so it will get flatter quicker

Yes I think that will apply to much higher current draw but we are looking here at parasitic milli amps, Rick