Leaving cars for long periods - suggestions for battery maintenance?

[Glowman]

I occasionally go away for a month or more and leave 2cars. Last time I did I came home to flat batteries on both of them - one blocking the garage door, want to guess where the battery charger was? I was wondering if anyone had any experience/thoughts/suggestions to offer...

One car is a 5 door TFSI (DSG) and the other is a 3 door 3.2 manual. The garage is a typical small garage and only just fits the 3 door - the 5 door is too long to shut the door.

I'd get a battery maintainer for the 3.2 but I'm worried that the battery mounted in the boot may be an issue with this with gas build up.

I have a solar charger that plugs into the accessory socket. I never expected it to keep the 'outside car' fully charged, but hoped it might offset some of the normal battery discharge. However that didn't seem to help at all when I last left the cars.

 

[ch1z64]

I find it strange that your battery die"s after a month its just that my car is left in a lock uo for 3weeks at a time anf i always have full battery once i come home.
Have you put a vcd's cable onto any off the cars and used the measure blocks to get the true voltage off your battery / batteries to see they are holding charge as it could be something within the car causing it to drain the battery power ever so little but enough over time to make it go flat .

 

[Daveyonthemove]

I sometimes work away for months at a time and have the same concern.
Before my last trip away I bought a portable jump starter. It has enough power to start the car easily and can also pump up the tyres (another issue with standing cars). They hold their charge for quite a long time (mine wasn't needed but would have started the car after 4 months easily) and can live in the boot of the car you are leaving outside if needed. Handy because if you start the car and go for a drive and end up stalling, you have the jump starter kit in the boot to get you on your way again.

 

[prt57]

How about a ctek charger for the car on the drive especially if you park it up close to the garage. The actual unit could sit in the engine bay with the power cable coming from the garage up and under the car.

I ruined an S3 battery due to not using the car during the winter months. Now I keep it on trickle charge and it is fine.
Also, do you need to keep the car locked in the garage as alarm, immobiliser etc all use up battery energy.

 

[SootySport]

I don't like the idea of trickle charging batteries long term, left on long enough they kill the battery. I would just leave the cars as you do now and invest as Daveyonthemove says, the jump starter.

 

[ch1z64]

All the lads above have come up with brill answers , but is not finding out why it is going flat not a thing you want to find out then fix . As i would have thought a good quality battery wouldn't be flat after being left for a month doing nothing . Worth investigating like if you where losing a lot off psi tyre pressure after a month you wouldn't just keep pumping it up you would investigate

 

[StuartG]

I have found an Accumate to be very good to keep a car battery charged & conditioned for extended periods - once it has hit target voltage it goes into maintenance mode monitoring battery voltage until voltage drops below a threshold whereupon it switched back into trickle charge etc - IE no concerns about overcharging.
A decent battery should cope with an immobilizer for at least a month but beyond that it may be too much to ask even if it is all working correctly.

 

[prt57]

This is how the ctek chargers work. Charges battery fully then monitor while the charge drops a certain percentage then it kicks in again charging back up to 100% followed by back into monitoring mode.

 

[paddy]

All sorts of things can kill a battery, alarms and blue tooth etc.
Buy a motorcycle trickle charger. i know sooty says you shouldn't leave a battery for weeks on trickle but modern smart chargers are just that..smart, I use an Oxford optimiser 3X on the bike and that can stand for 6 months in the winter...not cheap but neither are batteries

http://www.oxford-shop.co.uk/cat267_1.htm

 

[paddy]

Out of interest a car parked for a month is laid up for 720 hours. a 60A battery would last 30 days at 2A a day drain which is 0.083 amp an hour....so less than a tenth of an amp an hour, sounds reasonable to me.

 

[ab1702]

I find it strange that your battery die"s after a month its just that my car is left in a lock uo for 3weeks at a time anf i always have full battery once i come home.
Have you put a vcd's cable onto any off the cars and used the measure blocks to get the true voltage off your battery / batteries to see they are holding charge as it could be something within the car causing it to drain the battery power ever so little but enough over time to make it go flat .

Just because his battery goes dead after about a month doesn’t mean there is a drain in the car. Every car has a little drain, the radio is constantly taking power as it uses a very little amount to keep its memory, then you have the alarm and then the immobiliser on top of that. Over a month this is probably enough to drain the battery.

I don't like the idea of trickle charging batteries long term, left on long enough they kill the battery. I would just leave the cars as you do now and invest as Daveyonthemove says, the jump starter.

This guy probably can’t win because doing as you say and letting it go flat and then jump starting also is no good for the battery. Some batteries can’t recover once they have been drained and need replacing.

 

[Daveyonthemove]

You'd be unlucky if it drained 100% and killed the battery.
From past experience you can usually use the electrics but there isn't quite enough power to get the starter turning fully.
Having the jump starter pack should give it the extra needed to start the car without any issue.

 

[ch1z64]

Just because his battery goes dead after about a month doesn’t mean there is a drain in the car. Every car has a little drain, the radio is constantly taking power as it uses a very little amount to keep its memory, then you have the alarm and then the immobiliser on top of that. Over a month this is probably enough to drain the battery.



This guy probably can’t win because doing as you say and letting it go flat and then jump starting also is no good for the battery. Some batteries can’t recover once they have been drained and need replacing.

My point is everybody is given answers to keeping battery alive now if it was me experiencing this everytime i would like to know what was causing it.So there is something taken power from the battery even you said there is a drain off some sort so trying to find out what this is would be helping the member out just like explaining all the other devices that would help his battery . Like i said earlier if your tyre kept going flat after a month would you just pump it up and forget about it ?

 

[Daveyonthemove]

Probably the interior sensor constantly scanning.
Try turning it off next time you leave the car for long periods, it will probably prolong the battery a bit more.

 

[Gm95]

Anytime I know I'm going to have to leave a car for a while, I disconnect the negative lead from the battery and then lock the doors manually.

Obviously you loose your alarm doing this so not the best solution if they're somewhere where they need to be secure, but for me it's fine. I've left it like that for 8 months before, reconnected the negative lead and they turn over with no problems.

 

[SootySport]

Anytime I know I'm going to have to leave a car for a while, I disconnect the negative lead from the battery and then lock the doors manually.

Obviously you loose your alarm doing this so not the best solution if they're somewhere where they need to be secure, but for me it's fine. I've left it like that for 8 months before, reconnected the negative lead and they turn over with no problems.

This is your best option, I agree.

 

[RAF_S7]

I’m away months at a time. Been in **** since February, S7 tucked up in the garage, back in 8 days time

First time I went away after buying the car, I was away 2 weeks. Came back to a flat battery and had to call out RAC to get the beast started. Was told that there is so much electronics in the car that there is quite a lot of battery drain even when not running.

Got one of these here and always connect up before l leave to go anywhere.

Not cheap, but you can find on eBay at a reasonable price. Didn’t want to connect some cheap import to the car for months at a time without researching the product. This is the same charger you will find in Audi showrooms trickle charging their cars.

 

[Glowman]

Anytime I know I'm going to have to leave a car for a while, I disconnect the negative lead from the battery and then lock the doors manually.

Obviously you loose your alarm doing this so not the best solution if they're somewhere where they need to be secure, but for me it's fine. I've left it like that for 8 months before, reconnected the negative lead and they turn over with no problems.

That does seem the best option, especially for the car in the garage.

Does anyone know if leaving the battery disconnected for extended periods cause problems with the radio etc? I believe the radio is coded to the car with Audis so hopefully should need a reset code..

 

[ab1702]

That does seem the best option, especially for the car in the garage.

Does anyone know if leaving the battery disconnected for extended periods cause problems with the radio etc? I believe the radio is coded to the car with Audis so hopefully should need a reset code..

You should be fine if it’s the original radio for your car then it should come straight back on once you start it again.
Mines been 100% flat before and radio came straight back on.

 

[ab1702]

My point is everybody is given answers to keeping battery alive now if it was me experiencing this everytime i would like to know what was causing it.So there is something taken power from the battery even you said there is a drain off some sort so trying to find out what this is would be helping the member out just like explaining all the other devices that would help his battery . Like i said earlier if your tyre kept going flat after a month would you just pump it up and forget about it ?

What I’m saying is that it is normal for this to happen.
Every car radio takes power from the battery when the car is turned off so that it can keep the memory of the stations etc. Also the same with the alarm and immobiliser Because they are always active. So unless he disconnects these which I’m pretty sure nobody would do then there’s not much you can do unless you do as someone else said and actually disconnect the battery altogether.

 

[aqibi2000]

Disconnect the negative terminal of the battery if going for a long period of time and you’re worried. Just make sure it’s parked appropriately

 

[964kevin]

I don't like the idea of trickle charging batteries long term, left on long enough they kill the battery. I would just leave the cars as you do now and invest as Daveyonthemove says, the jump starter.

Thats errant nonsense. I have a summer time car on charge all winter on a Ctek, they keep the battery healthy. its full drain and charge that kills a battery,

 

[ab1702]

Thats errant nonsense. I have a summer time car on charge all winter on a Ctek, they keep the battery healthy. its full drain and charge that kills a battery,

I totally agree, letting your battery fully drain is worse thing you can do. If it’s not a fairly new battery then they can struggle to hold charge once they’ve been left to go flat