Hi all,

My battery has been draining very quickly so i've fitted an isolator switch as a temporary measure, but feel the alternator isn't charging the battery when driving as well as it should be either. Can anyone in the UK recommend a higher output alternator and where to buy one?

Thanks guys

 

Ask for Jack at Starter Motor and Alternator co of Plymouth. The unit you need is a B350 115 amp with a narrow pulley. they are really helpful and knowledgeable and have just supplied one to a mate of mine. All his charging problems were solved.

 

I'd start by changing the voltage regulator/ brush assembly. It could be that your brushes are worn and not making contact as well as they should, thus the poor charging. I've had that happen before.

 

If its a Lucas alternator, that requires major surgery. The Bosch is simply 2 screws, and your done.

 

Hi malchick69

All the above a great suggestions but, may be a stupid question, but have you actually put a meter on the battery whilst the cars running and checked its getting a charge/what voltage?

This would be my first point of call. As it sounds like this is just a theory at the moment. It could be for example the battery that is failing. I'd hate to see a fellow enthusiast spending money when its not necessary or on the wrong thing.

Rob

 

Yeah, as to diagnostics. I almost convicted the big 140 amp alternator on my LT1 powered "Lump".


But, I made a patch cord. To connect my HF sourced VOM to the car via the cigar outlet.
I could read volts at various loads and rpm's in real time. Alternator innocent, battery guilty. New battery and all was well.


Carl

 

Hi guys

Thanks for the replies. I put a meter on the battery when running and it was getting the right charge, but that was at stationary. I can't say what happens when i hit the road, apart from it isn't holding the charge. The battery was changed when i first spotted this happening (last week), so its brand new. The battery charge gauge on the dash reads at the bottom end of the NORMAL scale pretty much all of the time and when i leave the car for a few hours it is almost dead. I drove the car last week and when i pulled over for fuel the battery was dead. The mechanic said the pulleys were not tight, which he rectified, but he was concerned the battery does not charge all of the time when driving, so said maybe the alternator was intermittent.

I was recommended a supplier on this thread (B350 115AMP) and the supplier has just asked if i need a 'standard four groover' or 'single v', as a non techy driver can anyone help with which one i need? Its for a 1984 V12 HE.

Thanks for all your helps guys, its much appreciated.

 

He is referring to the belt that drives the alternator. Later cars used a multi ribbed belt, earlier cars used a single V shaped belt. It should be easy to tell just by looking at your belt/pulley: is it a single groove, or multiple little V grooves?

Multi groove: More Information for ROADMAX 4K425AP

Single V: More Information for DAYCO 17425DR