Thread: Disadvantages of a Generator

1. Dead flat batteries - yes, if you go away for a week leaving the lights on you will have a DEAD flat battery (don't ask!). ALso, last month the battery in the County failed with an apparent internal short reduciing the voltage to 1.5v.

2. Drawback of a generator. If you do not have any significant extra load, the one real drawback of the generator on these vehicles is that the rear bush needs regular oiling, and if neglected, particularly in dusty conditions, this will fail, allowing the armature to pole. I fitted an alternator to my 2a solely for this reason, after three generators. I never had any problems with lack of charge, but I do little night driving in it. Generally the only time you will suffer from lack of charge is if doing mostly night driving and a lot of it at low engine revs, such as in traffic, or as mentioned, when spotlighting.

In a Series 1 I would keep it original. There will be more maintenance than with an alternator, but you probably won't be doing high mileage anyway.
Do NOT fit a smaller pulley to get charging at lower rpm - the pulley size is chosen to safeguard the armature from throwing the windings at high rpm, and although there is a safety margin, I even using the whole safety marging will give little improvement, to get a worthwhile improvement will mean going beyond the safety margin, and although you may tell yourself you are never going to over-rev the engine, it will only take a fraction of a second, for example if the throttle sticks or it jumps out of gear, to destroy the generator. Because in an alternator the winding on the armature is cirrcumferential, this is not a problem with them.

John

Originally Posted by garrycol

My series 1 is still running a generator but has been converted to negative earth. The charging system seems to be working fine and the engine will run fine without the battery.

For a car of its vintage that is not going to have to support high electrical loads what are the disadvantages of staying with the generator over converting to an alternator.

Thanks

Garry

If it ain't broken - don't fix it

Originally Posted by garrycol

But even when the battery is flat, you can still push start a car with a generator but not one with alternator as battery power is needed to energise the coils in the alternator. Garry

After leaving my headlights on for about 15 hours, my car battery was pretty flat. I used jumper leads to start it and then drove home about 50 km. I tried to start the car a few minutes later and the battery was still dead flat.
I jump started again and drove another couple of km and found that the battery had begun to recover.
I always assumed that was because during the 50km trip home the battery was so flat that the alternator didn"t charge at all. The second jump start then created just enough current to get the alternator working.
I think that is an example of an alternator not charging a dead flat battery.