Battery / Alternator Advice
Turbo Mini Forums

Hi,

I had my mini rolling roaded recently and for a couple of days afterwards it was fine.

Now though a week or so later it really struggles to start, my first thought is the battery, which came out of the 998 i had, is not decent enough to start constantly my 1330 I now have,and also the alternator is not charging it enough, also from my standard 998.

Do you think a new battery/alternator is in order, consdering I am now running an alarm/immobliser, wipac lights, megajolt, cd player.

Heres a couple pics of the battery, give a idea on power etc.




Thanks

Jon

tbh honest the standard items should be up to the job. Test the battary and alternator to make sure they are working correctly before randomly changing items

You should be seeing around 14v at the battery when the engine is running/charging the battery. And around 13v when static.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

I have 13.1v, last night about 2 hrs after taking the battery off charge.

Am going to put the battery in tonight, and start the engine up and take the same reading.

Will see what this says.

Cheers

Jon

how do you mean it struggles to start? turns over slowly, doesn't fire?

O.k, battery now charged and showing 13.1V.

Put in the car and it started first turn of the key.

Took a reading when engine is idling and it shows 14.4V.

So all this suggests the alternator and battery are ok??

Only problem is that this all seem fine before and then it became difficult to start after a couple of runs, any ideas??

Thanks

Jon

fuelling?

is it a turbo? as the carbs sat atop a toasty turbo, the heat can evaporate the fuel in the carb and cause problems starting?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

alternator could still be on its way out. take it a logn ish run and measure the voltage engien running again :) i'll be its dropped off! earth straps also become suspect in this scenario!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

When you say it struggles after a couple of runs, is this when the engine is hot?

both, i can try and start it straight away and it struggles, come back the next day and just the same??

cheers

jon

what ignition system are you using?

I am running a megajolt ignition system.

Its an N/A engine.

I took it out for a spin when i got home and remeasured the voltage on the battery with the engine on, it read 14.3 V.

I then turned on, lights, rear screen heater, fog light and flasher, it read 13.3 V.

What do you think?

Thanks

Jon

How old is the battery?

Its highly likely that the battery is taking charge but not holding it for any decent amount of time.

You need to drop test the battery really. If it holds up well under a drop test then it should be fine to deal with the extras.

EDIT: From your reading under load it sounds like you might need a higher output alt.

What you need to do is test the current output (amps) under full load and then compare this to the alternator specs.

Say when your under normal load the alternator is putting out 15amps but when you turn everything on it goes to 50amps and your max alternator output is 50amps you really want to put in a higher rated alternater.

But you also have to think about how often all of these components are going to be running simultaneously....

Drop test the battery first, its the easiest thing to check.

Edited by James_H on 19th May, 2009.

i'd have gone with a power drain like an alarm or imobiliser

from what height do you recomend i drop it from to get the best results?

What is a battery drop test?

Cheers

Jon

Sounds like the alternator can't keep up. I'd switch everything electrical on measure the voltage, then switch one thing off at a time to see if the voltage increases.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Hi,

I havnt taken the mini out but over the past couple of days I have just been out and started it a few times and it has started right up straight away.

The key thing is that i have set the choke position and not touched it, i have been able to leave it as i havnt drove it. I am going to mark it in this position but do you think this is what could have caused the problem?

Thanks

Jon

I'd say battery at fault.

although it's showing good voltage when not under load. It is most likely suffering when trying to deliver cranking amps and the voltage would drop away under the load.

I did once have a bad engine earth that gave me trouble.

Hi,

Last night i tried to start the car and it turned over but would not fire.

I chucked the battery on charge for an hour, connected back up and it started fine.

Took the battery to be tested this morning and he said it was skimming a bit off the top end??

So the question is do I buy a new battery? If so what one should I get?

Thanks

Jon