Hi,

 

I need to leave the car unused for about 2 months and read that if not used for more than 3 weeks , the negative terminal should be disconnected. Wanted to know what readings will be reset or does it result in a factory reset to the settings. More importantly, being the RS model, the battery is in the boot and the boot is electric, will I be able to close the boot?

 

Thanks.

Dealer had to recode my car after disconnecting the battery. Driving aids mostly were not working and had some else issues.

I would inactivate the alarm and leave it just as it is. Being back just use some starting aid. There will be enough juice left in the battery not to mess the ECU up, but maybe not enough to start it.

I agree with Linni. I've been away on holiday with car unlocked in garage for around that long and it started no problem.

I'd assume diesel has a bigger battery than the petrols too which possibly helps. 

Thank you linni, snala for the inputs.... will probably ask a friend to start the car and idle/drive around a bit every few weeks instead of having to contend with the after effects you mentioned.. 

Edited 19 January, 20215 yr by ThreeSixty

16 minutes ago, ThreeSixty said:

Thank you linni, snala for the inputs.... will probably ask a friend to start the car and idle/drive around a bit every few weeks instead of having to contend with the after effects you mentioned.. 

Bear in mind due to the micro hybrid system that not much charging if any, occurs at idle and most of the battery charging from the alternator occurs on engine overrun/ and during braking.

You might be better off buying a smart charger/ or a solar charger plugged into the 12v socket.

2 hours ago, Kenny R said:

 not much charging if any, occurs at idle

 

sure about that ? asking as i leave have the aircon running with engine idle for approx 30 mins while my kid has a nap 

The car will charge the battery as and when it needs it, as long as it actually gets used. (Easily checked with a multimeter measuring volts across the battery, anything equal to or less than the 'off' voltage is clearly not charging the battery, anything higher clearly is).

A member whose username escapes me just now did some logs of voltage and current on his car recently, and it was clear that the car varied the charging voltage according to how the battery was at the start of a journey, and how the system voltage behaved during the journey, as well as doing the high voltage charging 'spikes' during overrun etc.  

Edited 19 January, 20215 yr by Wino

Interesting. By Overrun you mean coasting?  

 

I was intrigued by this micro hybrid term , does charging occur only during braking & overrun and not otherwise?  

On 19/01/2021 at 18:54, Wino said:

The car will charge the battery as and when it needs it

In addition to any high-rate charging that may happen during overrun/braking (foot off acc pedal).

Edited 25 January, 20215 yr by Wino

2 hours ago, ThreeSixty said:

Interesting. By Overrun you mean coasting?  

 

I was intrigued by this micro hybrid term , does charging occur only during braking & overrun and not otherwise?  

Charging occurs when the car wants it to. On older cars the alternator runs continuously and is always charging. Newer cars can effectively switch this off so the alternator doesn’t charge unless needed, reducing the load on the engine. 
 

When it does charge, it can do at a much higher rate and present a bigger load on the engine (thus charging the battery faster). So when you brake the alternator can present a bigger load on the engine to help slow you down and also charge the battery. Ideally it will only need to charge when you’re braking if you’re doing stop start driving. On longer journeys it will need to charge whilst driving at steady speed. 
 

Modern batteries are also more tolerant - they can cope with the car discharging the battery further (so it can longer with the alternator off), and also cope with being charged at a higher rate (so charge up more quickly when you brake). It all helps. 

If possible I would put car on charge: https://www.ctek.com/uk/seasonal_storage