6 to 12v

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Martin Benade
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6 to 12v

#1 Post by Martin Benade »

Does anybody know if the voltage reducer that Zims sells for wiper/sunroof motors can be used for wipers and 6v feed for the temp and fuel gauge? It seems like it would be workable. I talked to somebody at Zims today but he didn't know much about it.
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Brad K

Re: 6 to 12v

#2 Post by Brad K »

hey martin - i don't remember where (i'll check) but i thought a 356 vendor sold an entire conversion kit with the resistors for the gauges - i'll see where it was - brad

Kevin Wills
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Re: 6 to 12v

#3 Post by Kevin Wills »

I tried to reduce the voltage for my fuel gauge using a wiper motor resistor and it did not work. I ended up building a simple voltage reducer circuit for mine. Might make more sense to get it reworked by a gauge rebuilder.

Brad K

Re: 6 to 12v

#4 Post by Brad K »

Kevin Wills wrote:. . .Might make more sense to get it reworked by a gauge rebuilder.
it makes more sense to get 12V gauges!

i found these at Zim's - i don't know why the guy there didn't know - ask for Al next time

Drop down resistor for clocks, relays:

http://www.allzim.com/acatalog/Drop_Dow ... elays.html

Drop down resistor for instruments:

http://www.allzim.com/acatalog/Voltage_ ... 2e000_2eXX

hope this helps - brad

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C J Murray
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Re: 6 to 12v

#5 Post by C J Murray »

If you look on-line there are a variety of these sold for various uses. They are cheap.
'57 Speedster
'59 Sunroof
'60 Devin D Porsche Race Car
'63 Cabriolet "Norm"
'67 911 S Original Owner
'03 Ferrari 575M
'09 Smart Passion

Kevin Wills
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Re: 6 to 12v

#6 Post by Kevin Wills »

If you want to build something, here is what I based my circuit on: http://www.voltagecurrent.info/lm7806-datasheet/

The advantage of using a step down circuit was that it was so much cheaper than new gauges or getting mine reworked. It was less than $20 worth of parts to build and was an hour long project. A resistor will work too, but must be sized correctly; the wiper motor resistor is just too big for gauges. This is because the draw of the circuit alters the output voltage when using a resistor - more resistance is required with more current needed. A step down circuit with a transistor like the LM7806 will have a steady output voltage within the limits of the chip (for this one, about 1.5 amps).

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Martin Benade
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Re: 6 to 12v

#7 Post by Martin Benade »

Looks good. The LM7806 (and possibly a heat sink) is all that is needed to feed the gauges? I take it that the block diagram shown in the link just shows the inner workings of it?
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Kevin Wills
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Re: 6 to 12v

#8 Post by Kevin Wills »

Martin, it will need a couple of other components, but it is a simple circuit to build. I will try to dig up the diagram I used and post it this weekend.

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Martin Benade
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Re: 6 to 12v

#9 Post by Martin Benade »

I found a description of the wiring on the H.A.M.B. saying only that two capacitors (optional) were needed. Does that sound correct? Online elsewhere I found no diagram, but did pick up a virus!
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Martin Benade
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Re: 6 to 12v

#10 Post by Martin Benade »

One more question- will an electric tach work on 12 V using the 6 v power feed? And any circuit diagram for the LM 7806?
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Kevin Wills
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Re: 6 to 12v

#11 Post by Kevin Wills »

Martin, I checked mine last night because I could not find a diagram that looked like what I built. Turns out mine was based on a slightly different chip. Here is a link to the schematic:

http://www.electronics-lab.com/articles/LM317/

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Re: 6 to 12v

#12 Post by Kevin Wills »

Oh, and I'm not sure on the tach. Mine is mechanical...

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Jim Liberty
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Re: 6 to 12v

#13 Post by Jim Liberty »

Guys, I convert all my cars to 12V. The Tach., and speedo. only need bulb changes if they are mechanical. N. Hollywood will convert the combo. gauge. Brad Ripley sells a very nice step down for the wipers.

.....................................Jim.
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Conrad Carter
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Re: 6 to 12v

#14 Post by Conrad Carter »

Cool!

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Re: 6 to 12v

#15 Post by Conrad Carter »

How do I find Brad Ripleys site?

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