Some quick background: I have a '50 F1 that was my daily but got pretty smashed up on the highway a few years back. Been rebuilding it for a while and just got it back on the road. The gauges have always been nice but I had converted to 12v and just never got around to hooking them up properly. Enter the IVR. So I read that Ford – for whatever reason – used gauges designed for 6 volts well into the 70's and I think even early 80's. And the IVR (or instrument voltage regulator) is this fantastic piece of equipment that takes 12 volts and pulses it off and back on again through a set of points to average somewhere in the neighborhood of 5 or 6 volts. DONE. So I got one with the proper spade terminals, took great care in mounting it, wiring it, and proceeded to burn the (presumably) Chinese piece of junk out in the space of five minutes. Enter the solid state step-down regulator. And there it is. Also plastic. And VERY Chinese. I know for sure – it came straight from the country to my door. Much cheaper at around $7 to the IVR's 20-ish. But there has definitely been some thought put into this piece. The input can be anywhere from 3 to 40 volts, and output anywhere in that range. (Obviously you can't make more than what you put in) and the trickest thing is you have that dumb looking digital readout built right in! I actually laughed at the thought of that little display hidden under my dash but I'm here to say, I was able to wire it up and dial it in to 5.75 volts and my gauges have been ROCK SOLID for a few weeks now. Time will tell on the longevity but it's already outlasted the IVR by a mile. I bought a couple of them so I'd have a spare on hand but haven't needed it yet. The dash lights are all 12v in this pic. Only the gauges are running from the step-down.
Found mine on eBay searching "step down regulator" or maybe "adjustable voltage regulator". There are a few configurations. This one just looked to be the easiest to deal with. I did look for one stateside but couldn't find anything and even then, no guarantee it wasn't just someone buying in bulk from China and reselling. And here's the warm glow of 5.64 volts as seen through my empty speaker grille. I had also heard early ford fuel gauges read "hot" with certain sending units. That was another reason I bought a few of these. Figured I could use one at each gauge to tune them individually. But no issues – everything is currently running off of one reg and reading within a reasonable range.
Oh man, haven't hooked the amp gauge up to know if I'm charging yet. Left the key to my late model in Missy's car so had to just polarize everything and cross my fingers today! But I got to work, to an offsite meeting and back to the office and home so... so far so good.
The IVR is in the trash can now. All gauges are running through a single, adjustable, solid state regulator. (Check the last sentence two posts ago)
The regulator Kevin used should have more current capacity than is needed for just some gauges. I used LM7806 regulators - the 6V version of the usual 3 terminal non-adjustable regulators. I suspect that's what is inside the "runtz" units. At $0.63 each it is easy to use more than one and avoid the need for heat sinks. Wiring is the same as for the LM7805 or 7812 devices. Schematics are everywhere on the web - power in, out, and ground. Just another option. I use the imported switching regulators for other things and like them.
I also used the LM7806 for my 37 Chevy Ute gas gage, the only electrical gage, and it works flawlessly. I did mount mine to a piece of alum strip as heat sink, easy enough to ensure it stays good temp.
The Jalopy Journal
