Hi Time Machine

I often leave my 2008 Cooper S convertible for up to 5 weeks unused. It has always started on the first turn of the key without fail.

I do have a charger which will charge the battery and I can leave it on the battery and it will keep it charged without over charging it. I haven't felt the need to use it yet!!!!

I bought it from Halfords and its one of there own brand.

Minialf

 

I often leave my 2008 Cooper S convertible for up to 5 weeks unused. It has always started on the first turn of the key without fail.

even so, you'd probably extend your battery life if you use a trickle charger.

 

Any trickle charger will do you fine. I have an R50 that is parked up in the garage for months at a time and its kept alive on a trickle charge. I think I paid about £15 for this device about 15 years ago

 

Well for the best you need to buy a CTEK charger, BMW agree as they are happy to put their logo on it. Probably charge more for it as well but it might be worth it for peace of mind if you aren't a boffin.

 

You can purchase a BMW charger if you don't mind paying the brand price but any trickle charger will do to maintain the battery.

I use one of these and have used it to rescue a dead flat battery (took 3 days) and it will only charge what is required to keep the battery in good condition. Don't forget, driving a car will only put back the charge that was used to start the car and if your battery is in a very low charge state, your going to need a minimum 24hr trickle charge.
12V 5-Stage Car & Motorbike Maintenance Charger (0.8A / 3.8A, IP65 rated) | Jaycar Electronics
BMW/Mini dealerships have their cars on trickle charger to compensate for the parasitic drain on the battery from the ECU.

 

Exactly the same charger as mine Milpol lol

This wee charger has been one of the best investments I've ever made and kept countless battery's alive over the years and its currently keeping my R50 alive so if the car is needed it's ready in an instant

Sent from my SM-G920F using Tapatalk

 

Oh please!

My car lives outside and can sit for weeks without going flat, heck I've even left it for 2 months and it's still started!

And I still have the 14yr old exide mini original battery on it!!

Sent from my GT-N7100 using Tapatalk

 

I used to have solar chargers for my outdoor cars but I felt they were shyte so binned them

 

I use a CTEK trickle charger for my R53. It does the job well. The whole range is on Amazon. Paid around £35 for mine.