Battery Drain

Rialas · February 4, 2014

Regarding my original Contact (#38). The battery drain has now been solved and fixed. Armed with the information that the drain was in the circuit with a fuse of 'DC CUT' Lexus Milton Keynes were charged with finding the fault in no more that 2 hours. This they did and found a non-factory fitted box and wiring! At first it was thought to be an 'ELECTRONIC TRACKER' Fitted by the previous owner. However, this was far from the truth. It was an item manufactured by a company called Impact Secure and is usually used on lorries. Via radio the control box can disable the car, start the alarm, lock/unlock the doors and to the boot etc. The driver can have his own transmitter, or it can be done remotely!. To remove this item and all it's associated wiring took all day! Bless them Lexus MK only charged us the 2 hours. (How's that for Customer Service!). There were several fuses, two Ariel's, plugs and a whole heap of wiring. (See attachment enclosed). The drain has dropped from 1.5amps to about 0.29amps. Over Christmas, the car wasn't run for 8 days. When tried it fired up immediately. This problem has been with us for 51/2 years, so I suggest that if you bought your car second hand and you have a similar drain on that circuit, don't rule out the possibility of a non-Lexus addition. Regards Bil Levinson
That is interesting... but I cant see why it took 2 hours. Just take a fuse out or cut a wire !!

Like Supabil, I also would have wanted that pile of mess removed completely from my car.

Those of us who live with cars that only have occasional use, Battery drainage is a fact of life I'm afraid.

2-3 weeks is about the norm for any high end car.

I dislike trickle chargers and my preferred choice is Battery isolators.

Rialas · February 4, 2014

alphacat · February 7, 2014

Regarding my original Contact (#38). The battery drain has now been solved and fixed. Armed with the information that the drain was in the circuit with a fuse of 'DC CUT' Lexus Milton Keynes were charged with finding the fault in no more that 2 hours. This they did and found a non-factory fitted box and wiring! At first it was thought to be an 'ELECTRONIC TRACKER' Fitted by the previous owner. However, this was far from the truth. It was an item manufactured by a company called Impact Secure and is usually used on lorries. Via radio the control box can disable the car, start the alarm, lock/unlock the doors and to the boot etc. The driver can have his own transmitter, or it can be done remotely!. To remove this item and all it's associated wiring took all day! Bless them Lexus MK only charged us the 2 hours. (How's that for Customer Service!). There were several fuses, two Ariel's, plugs and a whole heap of wiring. (See attachment enclosed). The drain has dropped from 1.5amps to about 0.29amps. Over Christmas, the car wasn't run for 8 days. When tried it fired up immediately. This problem has been with us for 51/2 years, so I suggest that if you bought your car second hand and you have a similar drain on that circuit, don't rule out the possibility of a non-Lexus addition. Regards Bil Levinson
That is interesting... but I cant see why it took 2 hours. Just take a fuse out or cut a wire !!
Like Supabil, I also would have wanted that pile of mess removed completely from my car.
Those of us who live with cars that only have occasional use, Battery drainage is a fact of life I'm afraid.

2-3 weeks is about the norm for any high end car.

I dislike trickle chargers and my preferred choice is Battery isolators.

Batter Isolator is a good idea. . .

But as to the comment that 2 to 3 weeks is normal for a high end car I don't accept that. I had a new Audi S4 and could leave it for a month easily and did so on a number of occasions. 2 to three weeks doesn't cover a reasonable holiday. its unacceptable and if its common its bad design there is no need for it.

I am off to Thailnd next week for two weeks... parking at Manchester airport. I wonder..

SteveAvery · July 6, 2015

I have a red and a black SC430 - No, not extravagant; the red one replaces the black one, which is for sale - and both's batteries were flat after I returned from a 3-week holiday. I was surprised, as the red one is a recent purchase from a Lexus dealer. If this IS an inherent problem with these cars, as has been suggested, a solution would be to fit a Battery isolation switch under the dashboard and use that whenever the car will not be used for a while. I shall fit this asap to my red car. I know that this works, because such a switch is fitted to my 400hp Cobra (also for sale), and it always starts on the button, even after months of disuse.

SteveAvery · July 6, 2015

After more investigation on the Web, I found this solution:

"Turn off the automatic light switch. The one that controls the headlights. Our dealership told us that that has a constant draw on the Battery. Since we turned it off, no issues."

The automatic light switch is always set to the "on" position in both my cars; so, this could be the answer that you all need.

When the Battery runs down completely like this, is any permanent damage done? Is it wise to replace it with a new one, or does the exhausted Battery recover fully?

Paul_G · July 6, 2015

I leave my lights permanently in AUTO, and have never had the problem described here. My car is regularly not used for 2 weeks + and then only for short jourrneys...I guess they are all slightly different :)

SteveAvery · July 6, 2015

If turning the lights switch to "off" is not the solution, a Battery isolation switch would surely be. But then, would isolating the Battery trigger the alarm? I think I read in the manual that, if a thief disconnects the Battery, the alarm sounds, because it is powered by its own special Battery. If so, would it be possible for an isolation switch to disconnect both the Battery and the alarm circuit?

When the Battery runs down completely, is any permanent damage done? Is it wise to replace it with a new one, or does the exhausted Battery recover fully?

Rialas · July 6, 2015

I installed an isolator on mine. The alarm doesn't trigger.

When reconnected, it's good to go without needing any codes for the stereo etc. It's the simplest solution.

Rialas · July 6, 2015

Btw, very unlikely the lights in "AUTO" mode would make any difference to drainage with the ignition off.

John-F · July 6, 2015

Ours managed 3 weeks at Garwick over Christmas without problems. As a variation on a Battery isolator have a look at: http://www.batterybrain.co.uk

Not used one but was considering it for our MGF, it's Battery only makes 3 to 4 weeks if we don't use it.

SteveAvery · July 6, 2015

Thanks for the advice.

The Battery Brain is tempting, but I think I'll opt for the simple solution: an isolator switch.

SteveAvery · July 7, 2015

According to my local Lexus service centre, an isolator switch is not recommended, because it would disarm all security equipment. Obvious, really.

I shall contact your BatteryBrain company, to ask whether their product sounds the alarm when it disconnects the Battery, and report back here

SteveAvery · July 8, 2015

According to my local Lexus service centre, an isolator switch is not recommended, because it would disarm all security equipment. Obvious, really.

I shall contact your BatteryBrain company, to ask whether their product sounds the alarm when it disconnects the battery, and report back here

I received this reply from BatteryBrain:

"The alarm would sound if the Battery Brain Type III Gold 12V were to disconnect the Battery after detecting a drain. The solution is to bypass the 12 V supply lead to the alarm, so when the Battery is disconnected, the alarm still receives its 12 v supply. This will normally solve the problem unless the alarm has any additional feedback that senses the Battery has been disconnected."

Not being an electrician, I could not understand how the alarm can receive its 12V supply after the Battery is disconnected. Can anyone explain this answer, please?

John-F · July 8, 2015

What I think they are saying is that you have to run an extra wire (what they call the red accessory wire) directly from the positive post of the Battery (not through the BatteryBrain) to the fuse that supplies the alarm. However, it seems to me that if the majority of the Battery drain is coming from the alarm (as opposed to a light that's always on in the boot or faulty amp or even lights left on auto) your not really gaining anything. As long as you unlock the car before using the Battery brain remote to disconnect the Battery you would be ok but I'm not sure I would always remember! There is also the issue of any small print in your insurance, as they like any reason not to pay out.

We have had some success on other cars with a Battery conditioner. We even tried a (cheap) solar panel which added an extra week or so.

SteveAvery · July 8, 2015

What I think they are saying is that you have to run an extra wire (what they call the red accessory wire) directly from the positive post of the battery (not through the BatteryBrain) to the fuse that supplies the alarm. However, it seems to me that if the majority of the battery drain is coming from the alarm (as opposed to a light that's always on in the boot or faulty amp or even lights left on auto) your not really gaining anything. As long as you unlock the car before using the battery brain remote to disconnect the battery you would be ok but I'm not sure I would always remember! There is also the issue of any small print in your insurance, as they like any reason not to pay out.

We have had some success on other cars with a battery conditioner. We even tried a (cheap) solar panel which added an extra week or so.

You're probably right about not gaining anything. BatteryBrain is not the solution.

A Battery conditioner would solve the problem, if my car were kept in a locked garage. Unfortunately, it is kept on a driveway; so, I could not leave it plugged in via a cable through an open window to a power socket, with the bonnet open.

A solar panel is also not an option, as the car is covered by an opaque car cover.

It seems that there is no solution in my case, other than a simple Battery isolation switch, which then renders the insurance cover invalid, as you advised.

I could, of course, ask a neighbour to start and run the engine for a few minutes every 10 days or so. Not ideal, but it seems to be the only way.

As for the problem itself, my local Lexus centre genius mechanic said that the SC430 Battery is known to discharge completely after about 3 weeks. It is just a fact of life.

alphacat · August 16, 2015

My Battery drain problem was solved with a new Battery in the end. Even though I know there was a tracker fitted that had not been properly removed the real issue was the car was nearly 10 years old with the original Battery and if old batteries are under constant Battery drain conditions they don't recover and the charge drops more quickly than it would with a newer Battery in top condition. I was convinced my Battery was ok as I tried Battery testers I used a voltmeter and observed it charging up etc . In the end I fitted a new Battery a Varta silver Seal 4 year warranty bought on the internet delivered in a day and I fitted in in 15 minutes. Cost £68.

Result... on the old Battery when run down it would charge up with the engine running at 14.3 volts. even when on a long run this would only drop to about 13.9 volts .. The new Battery charges at 14.3 volts and after about 30 minutes this has dropped to 13.4 volts. I use a digital voltmeter fitted to the 12 volt cig lighter socket. Bought from amazon.

I have allowed the car to stand for over 2 weeks and the Battery voltage is still 12.2V on the old Battery that would be down to 11.3 volts and starting would have been touch and go. Job done.

Sold the car sadly but only need one car...

SteveAvery · August 17, 2015

Yes, I heard that, each time a Battery drains completely, its capacity to recover fully is reduced.

Two weeks of SC430 disuse should be OK, but three weeks is not, apparently.

I bought an isolation switch, and took my car to an auto electrician to fit it. He advised that, because of the rarity of my being away for three weeks, I should simply open the bonnet and disconnect a Battery terminal. So, that's what I'll do.

NEILJ · August 20, 2015

As ever this is always a hot topic aye. I mentioned in my update that it too is still an issue for me no more than a week and its get the Battery charger out and reset everything afterwards. Its a good job I love the car otherwise I would have traded it in for something much worse I suspect. I mentioned in my update that I am switching off the aircon when I garage the car, now I don't know if I am imagining it but it seems to give it a couple of days more in the garage we shall see. I have had a situation that I don't understand the other week where I had used the car on a Wednesday evening and gone to use it on the Friday afternoon and it was flat, two days !!!!!!!. Oh that was before I have started switching off the aircon. Sorry I, like many, can't add any solutions and only join in the whinge but it has been mentioned by my wife to go and get something else only to look up on forums and reviews and find most alternatives have much worse problems than the ones we are suffering. Lets say we are enthusiasts and we love the cars foibles or errrr NOT.

I have been off on summer break and have used the car most days with the top down and have enjoyed every minute even got complimented on the car in the M and S car park so not everyone thinks its ugly, not all bad its only the Battery they don't know about.

Neilj

Connoisseur · August 20, 2015

I started to experience a Battery drain problem 2 months ago; prior to that I had left my SC430 undriven in the garage for up to 4 weeks without any issue - would always start on first turn; I know the car was fitted with Tracker from new and it hasn't been removed.

So when the problems started (setting aside the need to also fit a new starter motor!) I got the original (11 year old) Battery bench tested and it was shot, not holding much of a charge at all. New Battery fitted (and new starter motor) and the car was transformed. It now sits happily for weeks again, though I do have one new issue which I have read about elsewhere - if I leave phone/iPod plugged into the cubby power socket and then switch off and lock the car then the alarm will sound repeatedly until it is unplugged.......

In a week's time we are taking the car to Murcia in southern Spain and back on a european road trip - 3000 miles plus, so a good run out :)

Paul_G · August 20, 2015

Neil, I haven't read back through all the posts, but i would certainly suggest a new Battery, Mine started perfectly and I had a few odd things playing up. A new Battery fixed everything. Even if you've had one recently, it could be a little under par :)

NEILJ · August 21, 2015

Paul

Purchasing a new Battery is on my list of to do's in the next few weeks and I will report back when its ticked off and complete.

Just getting over a crick in the neck after laying on the floor removing the front bumper to change the second HID bulb, Battery will be a doddle in comparison aye.

So thanks for the suggestion and point taken.

Neilj

NEILJ · December 28, 2015

Paul

I have forgotten to update.

A couple of months or more ago now I purchased a new Battery a Duracell which was on offer at Euro car parts and have to say so far it will do two weeks and start on the button without a murmur.

You were right and perhaps I should have done it sooner. The Battery fitted when I bought the car was a new one but possibly very cheap budget buy by the dodgy car dealership (not Lexus).

So so far so good and thanks for the help.

Neilj

jeffreyt · January 22, 2016

hadn't looked at the LOC forum for some months and I see this topic is still going strong.

I've given up on mine and decided its easier to sell it rather than keep looking for the dreaded 'leak'. Shame really as apart from that problem the car is now sorted.

An SLK seems to be favourite,lets see if the Stuttgart engineers can do any better.

Iwijon · December 16, 2016

I have the same problem with my 430SC. The Battery drains if the car is left standing for more than two weeks or so. I do have an electronic charger that trickles without overcharging but have now invested in a Battery Brain http://www.batterybrain.co.uk/

This is able to detect when the Battery is getting low and automatically cuts the connection to the car. It saves enough juice to start the engine again protecting you from being stranded and your Battery from being damaged. To reset you simply flick a switch and the power is back on.

A brilliant and simple to install solution

randyreindeer · February 22, 2017

New to SC ownership.

I had the Battery drain. Traced it to Two out of date Trackers which i removed. This let me leave the car a week before it would need recharging. Still not good enough but another break through has been finding that the alarm siren has a built in back up Battery. I havent pulled this yet or checked if its the cause but im fairly confident its not helping. Its a pain to locate. I can hear it when i set it off but pinpointing it is harder than i expected. Will keep you updated.