Morris Minor Owners Club

Ok then, so how necessary is an altenator conversion?
My old moggy still has the original 948cc engine and dynamo but has been converted to negative earth for a radio (which has since dissappeared!). When I start driving next year I will probably be using the moggy all the time as my every day car so I will be fitting a new stereo and a sat-nav (a must have with my sense of direction!) and probably some halogen headlights, so for these modifications should I be looking at getting an altenator or should the dynamo cope fine?

Thanks

Dynamo will be fine, Halogens take the same current as standard bulbs/sealed beam, so not a problem. Dynamo is also more reliable then an alternator. Sat nav only draws about half an amp, stereo about 5 amps at max volume.

With a dynamo you might have to top the battery up occasionally in the winter if you're driving to and from work with the lights, wipers, and heater on, especially if part of your journey is in stop-start traffic or queuing at junctions.

If doing lots of slow/traffic work in winter - you should go alternator. Often only £1 at autojumbles. They are v reliable- don't be put off.

Righto, thanks everybody, I'll see what happens for the moment with the dynamo but if a cheap alternator comes up i may consider!

Dynamo will be fine in summer - it's winter that's the problem.

The total load with halogen dip beam, heater and wipers is around 25A (main 26A), which is much more than a dynamo puts out, so the battery will discharge, whatever engine speed you are doing.

Adding a sat nav and stereo makes it >30A, so I would look for a 45A alternator to give plenty of capacity in traffic. The Lucas 18 ACR is 43A, and the 17 ACR is 38A - I would go for the higher output one if possible. There is an 23 ACR which is 55A, and was used on many of the larger engined Fords - it has a larger body, so needs a slightly longer fan belt.

The later LMA range was fitted to Minis and the like, and are quite common with 35A or more oytput.

Don't get the Lucas AC range, as these use a separate regulator and are more complicted to wire in.

Aye, I would second Richards comments - they fit well with my experience. Over the winter I found that (especially since my commute included a long stretch of stop-start traffic, mostly stop) the battery would discharge over a few days; and I'd spend quite a lot of time in traffic with either the lights only on side-lights, or the wipers not on, to try and keep the battery charging.

On the other hand, the standard Lucas alternators seemed to me to be the pits, I got through 4. I've now got a much later Lucas alternator fitted - and that's done a lot more miles without it's regulator pack expiring.

Headlamps etc don't add up to any more than 20 amps - which the dynamo can handle - otherwise BMC would have fitted a larger output dynamo! However it can only do this at decent revs - hence my note about traffic etc. Obvious point is- in heavy traffic, switch off the headlamps - which you should do anyway as a courtesy to the driver in front.

I'd advocate going to an alternator.

In standard form, the dynamo copes quite happily, but if you are upgrading headlamps, fitting radios, running the heater, lights and wipers in slow moving traffic (perhaps in stop-start traffic where the engine is turned off for periods of time) an alternator will get the battery back to health quicker than a dynamo.