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Wed May 02, 2012 5:05 am

I do not know the difference. I was at a bug show and a guy was saying the motor was on a "generator" but could easily be switched to an "alternator"

What's the difference? And why would you want a 69 Bug on one or the other?

Wed May 02, 2012 6:22 am

An alternator is better if you are going to be running a powerful stereo or other accessories that require a lot of power/amps.

Wed May 02, 2012 6:40 am

If your generator is working fine: leave it alone. Mine both are still on generators.

Wed May 02, 2012 6:56 am

Alternators are a more modern system and deliver constant and often higher amps at any RPM. Many of them have internal regulators too. The only other parts you would need to change out to run one on your motor would be the stand it sits on, and possibly a carborator stand/offset, both because of the larger diameter of the alternator. The wiring may be slightly different too. Your trusted VW parts house would help you get what you need, but be aware of these other items if you buy one at a swap meet.

Wed May 02, 2012 10:35 am

Wed May 02, 2012 11:21 am

NWGhiaGuy wrote: Alternators are a more modern system and deliver constant and often higher amps at any RPM.

Who needs modern on a 40-year old VW ???

Wed May 02, 2012 11:33 am

Cusser wrote: NWGhiaGuy wrote: Alternators are a more modern system and deliver constant and often higher amps at any RPM.

Who needs modern on a 40-year old VW ???

Those that have added significant additional electrical load.

Fog/driving lights that are actually used
High wattage headlamps (stock were only 35w)
High power entertainment systems
Air conditioning

Wed May 02, 2012 2:11 pm

It's like comparing disc and drum brakes, alternators are just newer modern technology and more efficient.

Alternators charge at a more consistent rate no matter what RPM where as Generators are barely charging at idle and are more drag on the engine.
THats why are gen bug idling at the stop lights with headlights on, wipers on, turn signals going and radio going will probably not be charging and may get a faint charge light glow or flicker.

Wed May 02, 2012 2:17 pm

As far as modern goes, beetles started having Alternators installed in 1973...So almost 40 years ago..

Wed May 02, 2012 2:39 pm

I have 4 VWs 61, 65, 69 and a manx clone on a 63 pan. All 4 have alternators. Just redid a 67 for someone and upgraded to an alternator. There are kits available, but its more involved than just switching the generator for alternator - fuel pump may need swapped and some single carbs have clearance issues. So - consider everything before making the change.

Wed May 02, 2012 3:40 pm

i would like to have air conditioning on my bug and i have a generator. my plan? buy the a/c first and then see about getting an alternator because it may not happen. until then i'll stick with a generator.

Wed May 02, 2012 5:20 pm

Joel is incorrect on this one
He says
"Generators are barely charging at idle and are more drag on the engine. "
In fact Joel you have no evidence of drag - it would be my guess that the alternator which has more stators would in fact offer more resistance to the motor at the lower RPS

Wed May 02, 2012 6:13 pm

The main power drag from an alternator or generator is the fact that it takes horsepower to make watts. If the unit was 100% efficient it would take 1 shaft horsepower to make 746 watts (that would be about 53 amps at 14 volts.) In reality it will take more because the alternator or generator is not 100% efficient. Since the alternator is generally more able to put out significant current at low rpm, and is rated for a higher peak current, the alternator likely to be taking more horsepower.

Wed May 02, 2012 7:29 pm

gooser wrote: i would like to have air conditioning on my bug and i have a generator. my plan? buy the a/c first and then see about getting an alternator because it may not happen. until then i'll stick with a generator.

I ran old-fashioned dealer-added DPD AC on my 1970 with generator for over 20 years, was plenty of electricity. June 2012 Hot VWs p. 60 the 1967 convertible there has AC, and a generator. Get an alternator if you wish when your generator dies.

Thu May 03, 2012 1:33 pm

I didnt mean A/C alone as much as a combination of those extra loads together. Also, heavy traffic with much idling is different than highway driving. The battery is there to "cushion" the load, so intermittent over draw wont hurt anything.

Chrysler made alternators standard in 1961. It was probably when high power solid state diodes became cheap that mass-produced alternators were competitive. The Germans were more than a decade behind Detroit just going to 12 volts.

Thu May 03, 2012 7:34 pm

You would probably encounter low charge in the scenario I mentioned earlier - idling at the stop lights with headlights on, wipers on, turn signals going, brake lights on and radio going if had A/C as well.

As you have the condenser fan, evap fan and compressor clutch and a couple of relays on top of all that.

Add all that up and it will be over the 30amp Gen limit.