Diesel Battery?

[redrobbie]

lads for some reason the guy who i bought the IS off, put a diesel battery in . Could this be why the starter turns over so slow.

[A1BMW325iSport]

not really unless it actually nackered, most likely you have a tired starter motor,

[redrobbie]

its one of those batteries with charge indicator, only thing is it always stays grey instead of green which at one stage it was when i charged it at home. It looks new, I dont want to screw up the alternator is it designed to charge up a diesel battery?

[Brianmoooore]

I think you've found out why the previous owner put a diesel battery on. - as an attempt to cure the poor starter performance.
Get a voltmeter across the battery with the engine running at 2000RPM +. Also try the voltmeter between the metal frame of the altenator and the car bodywork. Make sure you make good contact to clean bright metal at both points

[redrobbie]

I see! what measurements am i looking for regarding the battery and alternator.

What about between the alternator and the top of the manifold? And forgive me for being stupied but am i gonna be getting a reading off the metal case of the alternator?

[Brianmoooore]

14 to 15 volts across the battery. Turn the headlamps full on - should still be 14 to 15 volts.
You shouldn't find any voltage between the altenator and the bodywork.
Try between the altenator case and the manifold, and between the case and the rear bonnet catch/runner. Any appreciable voltage here, and you've found the problem.

[redrobbie]

Thanks brian ill let you know what I find . Thanks a1 aswell.

[Brianmoooore]

Further to what A1 said, how did the starter perform when you had charged the battery at home?

[redrobbie]

the starter turned over a bit faster but nothing like my mates 318i with the proper battery his starter runs well faster 2 sec turnover (sounds livelier).

Mine turns the engine over in bout 3-5secs (sounds weaker).

He says it could be the battery so i shud get my hands on a scrappy batt for Ԛ£10 quid but i want to save the tenner and put it towards a new batt if needed.

[redrobbie]

Brian I did what you said.

The battery:

motoquip Diesel 60Ah CCA @ SAE 605
CCA @ EN 640

I got 13.45 Volts at 2000RPM (Headlights on), I was driving the car for 30-45mins before. Is this bad . And no voltage between the alternator and bodywork.

[Brianmoooore]

14.45 is a bit inconclusive. The altenator's obviously producing power, but it seems a bit low.
Maybe a new regulator /brush pack for the altenator is in order, or try a second hand one.
If the starter was a bit slow with a fully charged battery then maybe the starter motor is past its best as well.
Pull the fuel pump fuse (11) with the engine running and let the engine stall. Then give the engine a good crank for about ten seconds.
Feel all the joints in the starter motor circuit (battery connections, starter connections, battery earth strap and engine earth strap), with your hand. If any get hot, then take them apart and give them a cleanup.

[redrobbie]

Right brian ill figure it out soon enough with the alternator, i think the starters past its best aswell. Thanks for your help though.