View Single Post
Old 07-09-2010, 02:43 PM   #6
Kevin in NJ
Senior Member
 
Join Date: May 2010
Location: South East NJ
Posts: 3,398
Default Re: Advice to change 6 volt to 12 volt Model A

Sponsored Links (Register now to hide all advertisements)
How big an electric heater??

You might be talking too big a load.

An very overlooked fact about alternators. Just because they are rated 60 amps does not mean they can actually produce such levels when installed on the Model A.

Look back to the days when you have a V belt and an alternator. Look up the how you are supposed to tighten the belt. You are supposed to get the belt very tight. The rule was if you could spin the alt pulley with a finger then it was too loose! If you tighten the belt to the belt tension spec you would have the belt so tight it would sound like a guitar string. If you look closer you will find the belt was also set up to go around the pulley to get a large contact area.

When mounted on the A there are several reason why you are unlikely to get maximum output. The pulley has a small diameter and the belt has a small contact patch. The small diameter is needed to get the RPMs up for the alt to work. To prevent water pump failure few actually make the belt very tight. It has been my experience that the belts are loose to very loose. The pulley on the alt can be easily moved with a finger. Some will even spin with minimal effort.
Any load beyond a basic load will cause the belt to slip.

So before you make your conversion you had best check the amount of amps the heater needs. A 150 watt heater needs 12.5 amps at 12 volts. That is a pretty small heater for a drafty A. Heaters are a resistive load, so it might work at 6 volts taking 25 amps. You could go to a 6 volt alt or a later high output gen and run the heater at 6 volts.

If you are going use a lot of amps then you best consider the condition of your water pump. As you are going to have to tighten the belt to get something more than a small fraction of current from the alt.

The best thing you can do for bright lights that let you drive 60 MPH at night is to get the direct replacement halogen bulbs that are made in Australia. They are found in the back of the A magazines and several parts suppliers now carry them. They can be bought in 12v and 6v. These bulbs will work fine with a generator on a 6 volt system. I think my brother has been running with the same bulbs for 8 years or so. He is running a gen with a diode cutout, no regulator.

There are options for radios today that could allow you to run off of 6V. Many only need 3 volts, you just need to be creative.

You also have to understand the going to 12 volts to fix any problems does not work. You will only mask problems that may come back to haunt you. So before you convert make sure your 6v system works 100%.

In any case, step carefully. You can spend a lot of money and not really be better off in the end.
Kevin in NJ is offline   Reply With Quote