Voltage Regulator?

[Chris]

I have a strange problem that started on its own. I have a series 1 2+2 4.2 l. I noticed that the charge dial on the dash has started to increase with the revs of the engine when in the past it varied around the middle by a small amount depending on the charge in the battery rather than the revs. The battery now loses charge in a week to the point of being absolutely flat (i.e. less than 1 volt on a test meter). I used to be able to leave it a month and the car would still start. I have replaced the battery but this has made no difference. I thought it might be the alternator but this seems to charge the battery fine - after 100 miles the battery is still fully charged. Is it the voltage regulator? Does anyone know who could help me please? I am fairly handy 'round a car but this one has me stumped.

Thanks in anticipation Chris

[Heuer]

Chris

Mike Frank has a very good two page charging system description here: http://www.coolcatcorp.com/faqs/Lucasalternators.html
and associated troubling shooting guide here: http://www.coolcatcorp.com/faqs/Lucasalternators3.html

You can use one of these gadgets to help diagnose simple problems: http://tinyurl.com/5f8ya7

Also check all charging system connections for tightness including earth. You could try disconnecting the battery after a run and see if it holds its charge. If it does could be something draining it e.g. faulty solenoid. Put an ammeter in series between the battery +ve terminal and the associated cable. With everything off drain should be negligible - clock only.

Once you have solved the problem consider installing a Voltmeter to replace the all but useless ammeter. Guide in the Upgrades part of the forum.

[christopher storey]

Just to add to david's suggestion about seeing if current is flowing from the +ve terminal, if you find a flow, you can identify which circuit is involved by pulling the fuses in turn

[Chris]

Thanks very much for your advice - I am in the process of trying this out