12v Gauges

I've been around dropping and regulating systems for a long time and all of them generate heat. Most are insulated from making contact with flammables. The flea-pay stuff doesn't look like it has any way to get rid of the heat plus it has a two wire input and a two wire output. How are you supposed to insulate your load from ground?

I would be skeptical about the longevity of those products and whether they are safe to use or not. You certainly don't want your car to catch fire due to a poorly made product. -Caveat Emptor-
 
rotorwrench,
I'm with you on the "flea-pay" stuff. I don't understand why everybody wants to complicate things. The NAPA #IR1 is what Ford did when they went to 12v. Works fine and lasts a long time and safe too. This is what I have on the two old Fords I have that are now 12v. Also, my '88 Ranger has this same unit to run the gauges!
 
rotorwrench said:
I've been around dropping and regulating systems for a long time and all of them generate heat. Most are insulated from making contact with flammables. The flea-pay stuff doesn't look like it has any way to get rid of the heat plus it has a two wire input and a two wire output. How are you supposed to insulate your load from ground?

I would be skeptical about the longevity of those products and whether they are safe to use or not. You certainly don't want your car to catch fire due to a poorly made product. -Caveat Emptor-
Click to expand...

Certainly doing what you know works is a good bet. "switching" power supplies and "buck-boost" converters are much more efficient than a dropping resistor of some kind, and really don't generate hots of heat. They are used in all kinds of electronics.
 
I used gauges from 70-80's ford trucks. they are exactly like , in appearance, to 40's stock movements. Also got matching senders. Used a Ron Francis VR-1 voltage reducer.
Newer gauge movements will fit exactly into the stock housings. Reassemble with the stock faces and no one will know the difference. May not match stock readings marked on the glass but once I got used to where they were reading, no problem.
 
I converted the gauges in my 47 ford coupe to 12 volt. Rodtechhrp.com provided a custom round hole plate that looks just like the original but with round holes for the gauges. I went with vdo Cockpit Royale gauges and they fit perfect and looks great.you will need to file the 90 degree corners of the dash hole just enough so they don't show through the gauge plate, but it was easy to do.

Sent from my SM-T800 using Tapatalk
 
Dug these out of the rat's nest. Some heavy ceramic resistors measuring 3.5 ohms each. I assume they were to supply gauge voltage.
 

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The big resistors are usually for fan motors or accessories with higher amp loading. They have high in-rush current and can damage intricate instruments in some cases. The old King Seeley type systems are pretty heavy duty but no point taking a risk.
 
I'm using NOS 46 gauges with a 12 Volt system. I just use a reduce I got from Drake. Its one that takes care of all the gauges. Works fine.
 

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Even though I'm getting ahead of myself here a bit, I've been playing with gauges. I plan a new thread to share what I learn. My instrument panel is really messed up, while removing all the nasty wire, I noticed that there wasn't anything holding it in so I just removed the whole thing.
 

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drolston said:
The horn is the trickiest. The horn relay must be changed, and that is not a big deal. But I have found no way to reduce voltage to the horn itself for which the horn still works. The horn actually works on +12 volts but sounds more intense. It might burn out if you laid on it too long.
Click to expand...

You can, and probably should use the 6V horn relay. It doesn't care about polarity and the 6V units had heavier contacts. The horn will be much louder and 'angrier' (I like it that way), but short blasts are the order of the day. The 12V relays can and often do stick 'on' and you have to pull a wire off the horn or relay to get the horns to stop. Never had that problem with 6V relays.

wga said:
From Ron Francis Wiring: VR1 is a clean easy setup for 12V to 6V conversion. No resistors to heat up. Connect to 12V, clean consistent 6V out the other end will take
care of all you gauges.
Next to what oil to use, the most discussed on this board. OP should take
some time and search for previous posts on 12V conversions.
https://www.ronfrancis.com/prodinfo.asp?number=VR-1 $60.00


https://www.napaonline.com/en/p/ECHIR1

$72.00 from NAPA
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That's the same kind of unit that Ford used up into the '80s. It's a chopper unit. It basically turns the full 12V on and off over and over again so that the gauges think they're only getting 6V. Works pretty good, but there are better solutions...that are cheaper.

I'm a fan of the fully electronic L7806 CVR. These little gems cost less than $0.10 each and can take anything up to about 19V and always output exactly 6V.

Only a CVR (constant voltage regulator) will produce a constant output of 6V. The choppers and dropping resistors will output some lower amount around 6V based on whatever input voltage it gets. So if your chopper puts out 6V when only the battery is connected at 12V, but your alternator is putting out 14V, the chopper will now put out 7V (or thereabouts). The only gauge that this matters on is the gas gauge. Even the stock systems will show one reading when going down the road at speed, but when you stop and idle and the generator cuts out and voltage drops slightly, the gauge drops too. With a CVR, this is eliminated.

You can get them at any decent electronics store, order online, and even eBay sellers have them. 1 will run the three gauges most of our old cars have, but they're so cheap, I always run one for each gauge. Simple 3-wire hookup - 12V in, ground, 6V out.
 
TJ.......I live just down the road from Classic and went to their OpenHouse last year. Very nice stuff, but you're right.....very expensive ! They had a '40 Standard unit that included a tach in the lower area of speedometer for $750 at the time. Really kool, but too much $$

Mike
 
What you really want for as little heat as possible is a series regulator as in 7806-8.
It just turns out enough for what you need instead of burning of the excessive like in a resistor or dropping diode (what you call runtz).
Next issue with a diode is that you got 2 failuremodes...open gages just stop working...shorting out gages have a chance of burning up...so make sure it´s big enough to cope with the dissipation.
Surrounding temperature is a big factor in how good any solid state dissipating heat works so dont stuff it in to tight.
 
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