3 replies to this topic

[Jack BRCG]

hi all.
in the process of finishing of yet another rebuild of my mini but come stuck with a problem.
cars been of the road for a year and the engine has been rebuilt,
fully charge my battery and put it in the car.
the engine turns over for around 20 seconds fine before it starts to slow like a flat battery. nearly starts the car but not quite. sometimes will start it if the car has been run for a bit.
checked battery earth, 2 engine earths and solenoid and all is fine.
when i take the battery out and put it on charge it says its only 1/4 from being fully charged.
any idea's???????
iv seen alot of people fit 096 batterys to a mini and am tempted but would the higher starting power solve any problems.
if i put a 2nd battery or jump on, then the car starts fine.
iv only got a halfords battery suggested for mini atm and its about 2 years old.
my engine is 1310cc pre A+ with lightened fly and has a new starter. the alternator is charging as it should (13.9 upwards when car running)
if anyone can think of anything to check please suggest.
im tempted with the bigger battery but dont want to shell out if its not the problem.

[Noah]

Check the condition of your coil.

Have you got fuel, if so how old is it. Modern unleaded goes off after a few months.

[KernowCooper]

Whats the battery voltage when its been standing for a hour,

12.65v is fully charged
12.45v =75%
12.24v =50%
12.06v =25%
11.89v =0%

you need to put a meter on the battery and check if its charging ok 13.7-14.2v engine running 1500rpm, then do the above tests, if you find they are ok then as you have looked at your earths and other connections I'd be looking at the starter which does show the symptom you have if all the other checks are ok. Starters have tired windings (was it new or exchange unit? some of the factors exc starters are rubbish)and brush and comm problems may be time for a strip and check the brushes and clean the comm, or depending on its condition a replacement unit.

I'd do the above are ok before doing anything else and buying a battery, and a bigger bigger battery will only give you a bit more reserve capacity, batteries that are not used get sulphated even at 2 years old

Just like to point out that some of the exchange units at factors alternators/starters and so on are rubbish, I have stripped some down and all they are is new brushes and a comm clean and a coat of paint and a new bedix if required.

Edited by KernowCooper, 15 February 2013 - 05:53 PM.

[Jack BRCG]

coil is all good. fuel is week or 2 old. battery charging at 13.7 or higher. will check battery voltage at standing later.
my only other thought is, as the engine is rebuilt, would it be tight causing it to need more power to the starter (jump/2nd battery) to get it to start?
it almost starts atm but not quite,