Car Battery Question
Car Battery Question
Author
Discussion

1Steve68

Original Poster:

128 posts

4 months

Friday 6th February
quotequote all
Not sure if this is the right section for this post as there are so many on here it gets confusing.
Sensible/Educated answers only please!
If (for example) you knew you were not going to be using your car for 3-6 months or more and didn't want to chance another dead battery would you leave the battery connected to the car or disconnect it? Genuine question.

MrBen.911

615 posts

140 months

Friday 6th February
quotequote all
I disconnect when leaving for a long time. Shorter periods, I use a CTEK conditioner.

2 sMoKiN bArReLs

31,675 posts

257 months

Friday 6th February
quotequote all
I always left mine connected but attached to a trickle charger/battery conditioner. (Assuming you have power nearby).

I've also left my Golf for a few months with no charger and battery connected and it was fine.

sherman

14,827 posts

237 months

Friday 6th February
quotequote all
Is the car used frequently just now?
If so it will be fine.
If its not get a CTEK.

1Steve68

Original Poster:

128 posts

4 months

Friday 6th February
quotequote all
sherman said:
Is the car used frequently just now?
If so it will be fine.
If its not get a CTEK.
Car was parked/SORN for 18 months.
Just had new battery fitted 2 weeks ago and it's back to normal.
Not going to be driving it much though so don't want to spend another £250 having RAC putting another battery in next time.


alscar

7,878 posts

235 months

Friday 6th February
quotequote all
Assuming you have mains power I would be connecting it to a CTEK battery conditioner ( MXS5 is the one to get -Amazon will be your friend ).

Huzzah

28,536 posts

205 months

Friday 6th February
quotequote all
Some cars don't like the battery to be disconnected in storage.

Ctek or similar would be best.

Steve Dean

88 posts

96 months

Friday 6th February
quotequote all
You don't state the make/model of car ..... however, most modern cars are fitted with an alarm and/or other electronic stuff that runs when the car is stood. If it is left for 3 to 6 months it will almost certainly flatten the battery (or run it down to a point where it may not recover). As has been recommended above, either connect it to a clever charger (i.e. something like a CTEK) or disconnect the battery and preferably store it indoors (and ideally connected to a charger). Even if you have an old fashioned charger, you can connect it via a mains timer so that it charges for just a few hours each day.

1Steve68

Original Poster:

128 posts

4 months

Friday 6th February
quotequote all
Huzzah said:
Some cars don't like the battery to be disconnected in storage.

Ctek or similar would be best.
Sadly no mains power. Private residents car park.

RizzoTheRat

27,894 posts

214 months

Friday 6th February
quotequote all
If you're leaving it outside, you can get solar trickle chargers. I bought an AA branded on that connects via the OBD port when I wasn't using the car much (I managed 9 months on one tank of fuel).

I've taken the battery right off my motorbike and brought it inside as I've not been using it for ages.

BertBert

20,835 posts

233 months

Friday 6th February
quotequote all
Huzzah said:
Some cars don't like the battery to be disconnected in storage.

Ctek or similar would be best.
Really? Why would that be and what actually happens to this car that has no power and can't do anything?

RizzoTheRat

27,894 posts

214 months

Friday 6th February
quotequote all
BertBert said:
Really? Why would that be and what actually happens to this car that has no power and can't do anything?
Some data can be stored in memory that needs a bit of power to maintain, so they can forget things if they're without power for too long.
A mate had this with an aftermarket Spyball alarm some years ago, battery went flat and the alarm system forgot the keyfob ID so he couldn't turn the alarm off once he'd charged the battery.
No idea how widespread this issue is with OEM stuff though but I wouldn't be surprised if various systems would effectively factory reset.

Edited by RizzoTheRat on Friday 6th February 12:56

sherman

14,827 posts

237 months

Friday 6th February
quotequote all
BertBert said:
Huzzah said:
Some cars don't like the battery to be disconnected in storage.

Ctek or similar would be best.
Really? Why would that be and what actually happens to this car that has no power and can't do anything?
No power for that long can screw up ECUs, sat nav etc.
Once the memory dies you cant get it back.

A CTEK is cheaper than a new ECU or AV unit.

paul_c123

1,745 posts

15 months

Friday 6th February
quotequote all
1Steve68 said:
Sadly no mains power. Private residents car park.
I'd seriously consider just selling the car, then buying another once you're out. With no mains power - and I'd not rely on a solar trickle charger, they're terrible - the car will die over that period of time and also lose value and be a hassle to get going. Not just battery, but tyres, built up grime, rust, etc. Cars don't fare that well from being stood a long time.

I've heard cases where manufacturer keyfobs etc can lose their coding to the car when left unused an extended period of time too.

ssray

1,274 posts

247 months

Friday 6th February
quotequote all
Solar panel charger in the window, assuming it's outside it will still work a bit indoors

s p a c e m a n

11,565 posts

170 months

Friday 6th February
quotequote all
The stuff in the garage is plugged in to wall chargers, the ones on the driveway have an oxford solar charger on the dashboard.

https://ebay.us/m/Jh2WJb

Ian_SW

924 posts

107 months

Friday 6th February
quotequote all
Other than a solar trickle charger, the easiest option would be to just take the car for a decent drive every few weeks.

Second easiest option would be to temporarily remove the battery from the car about once a month and charge it up inside your flat.

Both of those only work though if the OP is still at home but just doesn't need to use the car. They wouldn't be much use for example for someone who's been posted overseas for a year for work, in the army etc.

Personally, if it was one of the latter, I'd just sell the car and buy another one once I was back. It's not only batteries that degrade if a car isn't used, particularly when left outside.

1Steve68

Original Poster:

128 posts

4 months

Friday 6th February
quotequote all
sherman said:
No power for that long can screw up ECUs, sat nav etc.
Once the memory dies you cant get it back.
That happened to me on a 72 plate. Tech guy had to reset the system for over an hour on his comp just to get car started with new battery fitted.

Smint

2,765 posts

57 months

Friday 6th February
quotequote all
A CTEK dying on me one winter saw the scrapping of a nearly new large Varta battery.

I now have a NOCO Genius 10 smart charger, would have been interesting to see if the NOCO would have recovered that Varta.

BertBert

20,835 posts

233 months

Sunday 8th February
quotequote all
sherman said:
No power for that long can screw up ECUs, sat nav etc.
Once the memory dies you cant get it back.

A CTEK is cheaper than a new ECU or AV unit.
Just curious, but how does that happen? There must be a (rechargeable) battery that dies after a (long) time without power.