Alternators and batteries

[johnconradlee]

LuLU been running a bit rough the last couple of months, not liked starting from cold, hot not much better, wouldn't idle consistently, running really lumpily and down on power. I was blaming the winter plus the slightly ropey condition of my distributor and was wondering if I needed to look at the carb diaphragms as she seemed a bit gutless Driving down to Devon the other week.
Anyway, couple of nights ago the stater motor was a bit slugish (but she still started) so I thought with the short journeys at night I'd done that week at night I'd probably flattened the battery a bit so took it out of the car and put it on charge.
Put the battery back in the car last night and basically seem to have fixed all of the above issues. Idles nicely, even the slight misfire has gone, starts easier, picks up better, frankly like a different car.

I'm now wondering why my battery isn't charging properly. It's obviously charging at bit, but the ignition light glows dimly at idle with the (halogen) headlights on. With the direct to battery bypassing the ammeter wire removed so I get a reading I don't seem to be getting much charging below about 2000 rpm so I'm wondering if a smaller pulley would help.

The alternator is a Lucas 18ACR equivalent supplied by Chris Witor circa December 2012 so I'd be irritated if it's failing already. The battery is of a similar age but a bit on the small side as a Varta 063 as opposed to the recommended "biggest one that will fit" 096 but I would have thought should still be ok.

[Alec]

Hello John,

I don't believe the battery capacity is relevant, (I'm not an believer of the bigger the better philosophy) as that only means that you have greater cranking capacity. If the car is in good order that is not really that important.

There seems to be a problem if your general indication seems as though the charge rate is low. Initially I would check connections are sound but it is possible that the alternator is below par. Do you have a meter with which you can check the voltage. Also don't forget the simple check of belt tension or condition? I don't feel that you need to look at pulley diameter.

Alec

[CAR]

a loose or dirty connection at the battery terminals would do the same too John.

Colin