Well were do I start
I've charged the battery up and tested it. It reading just under 14volts
Installed the battery and tested from the alternator to the battery giving me a reading of 11 volts
I've started the car and my incar volt meter gauge was giving me a reading of 11 volts but after 10-15 minutes of running the gauge gradually drops down to about 6volts.and there's ABS,oil lights appear on the dash then starts running rough do to the spark plugs not firing as they should then conks out on me. Try to start the car again and I just get half a turn then clicking noises indicating flat battery.
I've had the battery tested and it's ok.
Some one please help shine some light in my situation
Thanks

 

Did you drop test the battery?.

 

Just an update when it cuts out because it's lost voltage when I leave it off for 10 minutes the voltage meter In The car will rise back upto 10volts and then u can start the engine again really weird

 

Not weird. Called surface charge. This sounds like an alternater issue. Test the voltage at back of alternater and battery with engine running. You should see the same voltage at both. Anywhere between 13.5 and 14.5 volts is acceptable. You dont say how youve tested the battery? A voltage test on cranking over a 15second period is a good way of testing. Min 12.2 volts in battery. Disconect crank sensor and crank engine for 15 seconds while waching voltage. If it drops below 9 volts at any stage during the test replace the battery.

 

After putting the battery on charge and the charger saying full when finished. I installed the battery started the car and tested the battery terminals giving me a reading around 12 volts and like you said above test the alternator from the back to the negative battery terminal and yea it's giving me the same reading!!
I took my old alternator off today and replaced it with a second hand one.
BUT STILL exactly the same outcome as above

 

What was the reading at the alternator/battery with engine running? as above do a crank test? testing voltage on a static battery doesnt tell anything about the battery condition other than the voltage

 

The reading with the engine running was just over 11volts. Just a quick one which connector is the crank sensor the one on the right near the oil filler cap??
Cheers

 

Just re read. I guess you have 12 volts with engine running? Thats to low. Does the battery light on the dash light up with ignition on? Do you have power at the ind side of the alternator with ignition on? What voltage do you get with engine running and lights on?

 

No. Crank sensor is under the alternator