Starter motor woes ?

[theHotHead]

Hi all. I've got an 06 Tamora.

I had my car locked away for just over a year on a SORN and took it to get MOT'd today. The battery was low (reading 5v) and the type 069 battery I bought to replace it didn't fit - the terminals were roughly 1 inch too high so I charged the old battery for a couple of days. After leaving it for another couple of days unconnected it read 12.7V.

After fitting it a few days ago I noticed when turning the key when the engine goes to turn over I get this slow sort of "trying to turn over" whir .. as if the battery isn't powerful enough. The battery definitely reads 12.7V at the terminals and the car does start after a couple of seconds. When driving I get 13.5V as a reading which sounds correct. The car passed it's MOT and I drove it back to the garage.

Every time the key was turned I got the sound like the engine wasn't going to start .. but it did each time after a few secs. I'm trying to work out whether or not that sound of the engine trying to turn over is the starter motor and if it is could it be that the starter motor has ceased slightly due to being in storage for a year ? Would you expect the motor to free itself when I drive it regularly ? I am a numpty when it comes to how cars work by the way so please excuse my crude descriptions.

Any thoughts/suggestions greatly appreciated.

Kevin

[steve-V8s]

If you let a modern battery stay discharged for any time the cells will sulphate, a layer of hard sulphur builds up on the plates effectively reducing the capacity, this process is not reversible. A sulphated battery will reach full charge very quickly because it only has a small capacity available to charge. Obviously it will also have a greatly reduced ability to deliver the high current requited to crank the engine.

[theHotHead]

Bummer. So although I am getting the correct voltage across the terminals I'm not getting enough current to crack the engine .. potentially ??

[steve-V8s]

I would think the voltage falls off when you try cranking.

[shep1001]

theHotHead said:

Bummer. So although I am getting the correct voltage across the terminals I'm not getting enough current to crack the engine .. potentially ??

Correct. The CCA (Cold cranking Amps) of the battery should be about 650/600A it will be no where near that on a knackered battery. Volts drop too, watch it on the dash display as you crank her over 8-9v would be my guess at peak load.

You can confirm it's not the starter by jump starting the car, I suspect it will turn over just fine.

Shep

[theHotHead]

Thanks peeps .... I'll swap out the battery. What you've written is ringing some bells now ... I remember changing the battery the last time the battery went flat and the car started with no fuss whatsoever - when I was in a similar position before - my memory has now been jogged !

Cheers )