6 Volt Bus Conversion to 12 Volt Charging Notes

by Joe Fournier

There was generally agreement on the following points regarding a conversion to 12v from 6v (though not all who responded to the mailing list poll addressed all points):

  1. Wiring - doubtful that any wiring needs to be replaced, as 6v systems tend to have more amperage pumped through them than do 12v systems. amperage is really the deciding factor, so I infer that a 12v replacement that draws more amperage than the origian 6v item probably warrants consideration of whether the wiring can handle the change.
  2. Bulbs - will be very bright and hot for a short period of time, then they will cease to work. I infer that there's a small risk of damage to nearby stuff as the bulbs overheat (don't forget the e-signal bulb).
  3. Fuel sender - does not need to be changed; it's a resistive element and the same elements were used in 6v and 12v units.
  4. Fuel gauge - there were different gauges for 6v and 12v buses. Dave Easterwood is certain you can run a 6v gauge in a 12v bus; another respondent (Justin) confirmed that he runs a 6v gauge and sender in his bus and it works fine. Lucky for me, I have a spare 12v gauge, so it's a non-issue.
  5. Clock - running a 6v clock on 12v will fry the points in the clock. (If you've never seen the inside of a VW/VDO clock, they're simply elegant. They really are wind-up clocks, wound every couple of minutes by a set of points making contact. I picked one up at a junkyard a few weeks ago and was able to fix it in less than an hour of tinkering (though I'd never seen the inside of one before). I ain't no Eisenstein, they're just that simple...and elegant.)
For many items, such as the clock, voltage drops can be used.

There are lots of other things I didn't ask about because I think I know the answers. Please correct me if you know I'm mistaken:

Wiper assembly - 6v runs very fast, putting extra stress on bushings and in many cases eventually frying the assembly.

Starter - 6v winds up fast, but again, often dies an earlier death if run on 12v.

Radio - 6v run on 12v would fry almost immediately. Use a voltage drop or upgrade to something better than an AM radio. ;)

Switches - shouldn't have a problem, except if they have bulbs, which need to be changed per above.

Generator - specific to 12v or 6v - don't interchange.

One more thing...I THINK I can run a 12v radio by tapping juice from 2 6v batteries in series. I know I'll have to do this in such a way as to isolate the power between them, but I think this is similar to the issue of how you run an auxiliary battery. Since I have a 6v gas heater that I'll consider installing at some point, a second battery is a real likelihood for me.

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