TheSamba.com :: View topic - Voltage Drop installation for 6v on 12v question

Wed Oct 17, 2012 10:14 am

Hi everyone! Looking for another install tip on "how to" for my 65 bus. My bus is a 12v conversion but I still have a 6v gas gauge that I really need to use. I understand that I can install a "voltage drop" to be able to use my 6v gas gauge. Anyone out there done this? What are the step by step instructions to do this? As always, I'm deeply indebted to all those fellas who've helped out before on my other issues. I'm an eager beaver so I'm willing to learn.

Wed Oct 17, 2012 10:38 am

I've been running my original 6v gas gauge on straight 12v for 6 months now and it's still working great and reads accurately. I wasn't sure what to do about it either when I wired mine up, so I did some reading on here and found lots of posts of folks who have ran them on 12v for years with them still working. Definitely need to change the bulb to a 12v bulb though.

There were some people who said it didn't work well for them (either didn't read accurately, or eventually quit working), so I can't promise it'll work for you, but it has been working fine for me.

Wed Oct 17, 2012 12:26 pm

various ways to do it. Leave it be, make a regulator yourself, buy a voltage drop, add a resistor to the power line to guage. I made my own using the Lm317 voltage regulator found at radioshack. The circuit diagram is on the back showing how to use it . The Lm317 is an adjustable voltage regulator, so I adjusted mine up voltage wise just enough to get full gas gauge needle deflection. If you dont want to make your own, resistor it or buy a voltage drop. If you go the resistor method, then youll have to measure how much the guage resistance is with sender connected(with no power applied, or you will damage your ohm meter!!). Use that resistance to determine current drawn at 6v. Then select resistor to drop 6volts using the current value. All of this figured out using I=v/r formula. Only other way is to go to radio shack and buy thier 100 pack of resistors, and substitute ohm values until you get the resistor to drop 6 volts, leaving the other 6 volts for the guage to drop.
I used to run my guage at 12 volts but decided to give it the proper voltage. Read that sometimes the straight 12 volts method can make the needle snap off.

Wed Oct 17, 2012 1:17 pm

good feedback fellas! love the support. I will definitely see if I can pull this off :D

Thu Oct 18, 2012 8:05 pm

One more happy 6V gauge on a 12 V system user. Have run the 6V fuel gauge on 12V on at least 3 busses and have never had a problem. Current one I have had for about 8 years and it still works fine with correct readings.

Thu Oct 18, 2012 10:02 pm

12v was an option from the factory from about 195?
6v gauges will always work just fine for decades
same with the sending unit its like a headlight switch or any other switch in your bus it just doesnt mater how many volts run thru it
have fun with your bus !!!

Fri Oct 19, 2012 12:36 pm

I'm surprised no one sugggested what I'd consider the most
practical thing, simply save your coins 'till you got the price of a 12
volt gauge. Their not that pricey and come up on this site fairly often.

I absolutely hate voltage drops, regulators and gadgets.
To me their just extra "smodge" in your wire system. I try to keep my '63 15 window as stock as possible. Thats part of my enjoyment
of the bus. From what I've read 12 volt was an option as far back as
1963. That was for police, fire, and ambulance use.
You can bet your bottom dollar, when Volkswagen delivered an
upgraded vehicle to the customer there were no voltage drops,
heat sinks, or other "smodge" to "trick" the electrics from 6 to 12 volt.

I've owned my bus eighteen years. It was all ready upgraded to 12 volt.
When I first got it, I kept my six volt gas gauge nearly two years untill I got the correct 12 volt gauge. It worked okay, just wanted the right gauge
for the system. Same deal with the windshield wiper motor. It hadn't been changed out during the conversion. After checking I decided to swap my
6 volt SWF motor out for a '68 bug SWF wiper motor.
An identicle motor except for being the desired 12volt. "Works good,
last a long time" as the expression goes.

I even changed my radio, a SAPPHIRE IV AM/FM, a normaly six volt
radio to 12 volt. Its wired in using the standard VW system with
an original reconed speaker, just like it came from the dealer.
When working/troubleshooting my bus for electrical issues, I use the standard 1963 wire diagram with the only exception being I'm aware everything is 12 volt.

Once again, no "smodge" with trick box's, heat sinks, voltage drops
or what have you.
Just my two cents :D

Sat Oct 20, 2012 8:38 am

I, too, have used a 6V gas gauge for many years and upgraded to a 12 gauge recently. As long as the ground wire from the tank is good and the signal wire to the dash is good, the original fuel gauge is good for a few decades of use.

I've had my '66 for twenty years now.

Sat Oct 20, 2012 2:38 pm

Id bet you couldnt find my voltage drop unless you had a half hour to find it, :lol: . Since Im already good in electronics its nothing for me to bust out a voltage drop, plus as long as my og to the bus guage works, Im giving it what it wants. I already have run it 10 mor more years on 12 volts.

Fri Apr 11, 2014 7:33 am

I put a 12 volt 2speed wiper motor in my 65 sc. I thought I could install a 2 speed wiper switch but that idea doesn't work so easily work in the 65 dash.
Can I still use the original 6volt single speed switch with the 2 speed motor ?

Fri Apr 11, 2014 10:12 am

Only if you pick one of the speeds to run it with.

But you cold put a double-pole single-throw switch behind your switch and run the "on" wire to the middle terminal then each outer terminals to the slow and fast connections on the motor. Reach under to pick which speed you wanted.

Fri Apr 11, 2014 12:28 pm

far rider wrote: I put a 12 volt 2speed wiper motor in my 65 sc. I thought I could install a 2 speed wiper switch but that idea doesn't work so easily work in the 65 dash.
Can I still use the original 6volt single speed switch with the 2 speed motor ?
use a headlight switch and a single pole double throw relay and you will have 2 speeds. I use the chevy blower motor relay but doesn't matter what style of relay. Relay function separates parking lights and headlights of switch. So parking lights is low speed with relay coil not energized. High speed triggers relay coil to switch relay contacts to the high speed only relay terminal. Suppose if you wanted, you could take apart the headlight switch and modify the contacts.

Fri Apr 11, 2014 6:53 pm

Sheesh; I meant single pole double throw. So, quartermilecamel, why would he need the spdt switch with a headlight switch? Couldn't the parking light be low and the headlight be high wired straight up to the wiper motor?

Fri Apr 11, 2014 10:36 pm

my switch has the parking lights on when the headlights are on so that's what I used. 1st pull of the headlight switch has the parking light terminal on. 2nd pull of the switch has the parking light terminal and the headlight terminal on. So if I pulled the switch out to the 2nd position, it would turn on both low and hi of the motor. My wiper motor needed low or high speed but not both on at same time. I do remember someone saying in another thread that their parking lamps weren't on when headlights were on so not sure why or what switch they had.

Sun Apr 13, 2014 2:30 am

^^ So what if you ran it the wiper motor to a headlight switch and used the dimmer pole to the higher speed pole of the wiper motor ??
Thus giving you an adjustable speed motor ... :)

I've been wondering this ever since I set up a blower motor for a heater
on Kevin "The Key Guy's " bus for the shasta trip Using a headlight switch on the dimmer pole so he could control the fan speed on the blower motor...

Seems to work great !!
And so far no issues to date ...

One of us needs to go & try it out on a wiper now , LOL :lol:
Be pretty cool IMO to be able to fine tune the speed when needed :wink:

Plus , it would be using stock VW parts & no volt drops / etc. !!! 8)

Hmmmm ..... :-k :) :)

Sun Apr 13, 2014 5:40 am

My bus has a volt-o-drop thingy on it, very small, finned( for cooling I think) and works nicely. That said I will more than likely change the Arm. in the wiper motor over to a WW 12 Volt Arm. Have any of you guys used one??

Sun Apr 13, 2014 6:19 am

Big Bill wrote: My bus has a volt-o-drop thingy on it, very small, finned( for cooling I think) and works nicely. That said I will more than likely change the Arm. in the wiper motor over to a WW 12 Volt Arm. Have any of you guys used one??

I just did the WW armature replacement about a month ago, super easy and works great. It was a little noisy at first not bad and I did notice the more I ran it the quieter it got.
Now I want to replace it with a two speed motor and healight switch combo.

Sun Apr 13, 2014 12:08 pm

fresno james wrote: ^^ So what if you ran it the wiper motor to a headlight switch and used the dimmer pole to the higher speed pole of the wiper motor ??
Thus giving you an adjustable speed motor ... :)

I've been wondering this ever since I set up a blower motor for a heater
on Kevin "The Key Guy's " bus for the shasta trip Using a headlight switch on the dimmer pole so he could control the fan speed on the blower motor...

Seems to work great !!
And so far no issues to date ...

One of us needs to go & try it out on a wiper now , LOL :lol:
Be pretty cool IMO to be able to fine tune the speed when needed :wink:

Plus , it would be using stock VW parts & no volt drops / etc. !!! 8)

Hmmmm ..... :-k :) :)
Well Im using a beetle 2 speed wiper motor. High speed is faster than the single 12v speed motors that I have. Would like to know what kind of blower motor and amperage the blower motor pulled cause the dimmer was meant to power 3 small light bulbs, fuel guage and 2 for the speedo. Too much load and the nichrome wire in the dimmer will burn up. I remember vaguely thinking about trying just that....wiper and dimmer. Cannot remember if I did. That was 1997 before samba time.