7 replies to this topic

[macnavi]

(Mini Mayfair 1989, 1275cc)

Hi all,

 

I know battery issues are difficult to solve over the Internet, but everybody I know knows his mechanical stuff, but don't like electronics. I do like electronics, but in a Mini those cables are all bundled together in the loom, that I still haven't figured out where things go.

 

Anyway, the issue is: the battery is drained when I want to start it after nearly two months. Happened today and happened the time before. The thing is: when I connect it to a battery charger ("Save A Battery"), it indicates 12.5V, but within 10 minutes it is at 14.4V. After 20 minutes it dropped to 13.5V and is staying on that (??). I can't explain this behaviour. But it seems to me that the battery wasn't drained, but just didn't have that little bit to get it started. When I have a freshly charged battery, the Mini starts first try.

 

Last year, it actually did stand still for five months and then the battery wasn't drained. Not that it would start immediately, took me a few minutes to get it going, but the engine was still turning over. Two months ago and now, after two tries, it obvious to hear that it is not going to do that.

 

The issue started around the same time when my rear lights failed. When turning on the lights, the fuse for the rear light and dashboard light would jump. We couldn't figure out where the short was, so we made new connections from the rear light cable inside the engine bay to the fuse box and a new cable from the dashboard lights to the fuse box. That solved the problem. I can't imagine how the old cables would affect the drain, as they are not part of the circuit anymore. I'm not sure if these issues are connected, as I was not able to drive my Mini at all around that time.

 

I not a complete blank on electronics, but I have no clue how to measure a possible drain of the battery. The battery is from 2010, Halfords 330 amps HB053. This was advised by Halfords for this car. Am I using the correct battery? Normally the current is 13.5V, but shouldn't it be at 14 or above?

 

Any advise is much appreciated.

[grck1]

I would say the battery's had it.
It's five years old and has died from sheer lack of use. Being charged then left to discharge is a sure way to kill one
They need regular charge and discharge cycles to live long otherwise they suffer and sulfate up. Which severely reduces the battery's capacity hence your readings when charging.
I would suggest getting a new one and either using the car regular and by that I would say at least once a week and physical driving not just starting it in a garage. Or investing in a quality battery monitor to protect and cycle the battery regular.

[Alpenflitzer]

Are you sure the battery has 330 Amps? My battery which is a  Bosch S5 12V61 Ah which is more than the Mini usually has, namely 45 Ah

On the other hand 5 years is a long life for a battery.

Edited by Alpenflitzer, 26 September 2015 - 01:41 PM.

[maximas]

Once you replace the battery....buy an optimate and keep it ticking over...I have these on both my classics....only cost £1 per year to run..no more probs.

[macnavi]

Thanks for the replies. I didn't know they wouldn't last long. It does make sense. Any tips which good one to get?

 

@Alpenflitzer, it really says in large font on the top 'Starting power 330 amps'.

 

@Maximas, do you mean with "optimate" a battery charger (had to Google it). I have this already, that should do the same. It's just a fuzz to get it out of the booth, but I guess I'd better start using it. Don't have a garage, otherwise I could charge it through the cigarette lighter socket.

[grck1]

The 330 usually with cca next to it refers to the cold cranking amp power, ie for starting purposes.

The other measure ie 45ah is the power it will give out continually over I believe a hour before going flat. They measure them two ways for the different purposes they do, starting and then running / maintaining the electrics in the car

[macnavi]

There is no other number or info on the battery, unfortunately.

[maximas]

One of my cars is on the drive.....I plug the optimate in...in the front room....I fed the cable under the floor and out through an air brick...then permenantly fixed the wires to the battery...then extended them under the car and fixed the end plug in a discreet place under the rear bumper...I now just reverse the car on the drive and plug the optimate in when the car won't be used....then monitor it if needs be while watching tele....