Hi folks. Your fuel gauge cares much less about voltage than you might think. After a long and involved study of these (and some other balanced magnetic schemes), I can tell you 12v will only harm your fuel gauge in one particular aspect: there is an hourglass shaped permanent magnet at the base of the needle in your fuel gauge...this is very important in determining the accuracy of your gauge. I've written about this before and I've posted images of it here. If your gauge has been run on 12v the magnetism of that hourglass shaped piece of metal will be changed...increased, actually. And nobody has any way of telling us how long it will take...there are too many important variables. Some people think it could only take a few hours and some think it could take about 1 day. This means it (your gauge) will never again register correctly if run on voltage less than 12...but your fuel gauge won't be burned out. So for anyone buying a Runtz device, it is probably not necessary. However, if you think you want a voltage reducer, please send me a PM or an email and we can talk. I made a sophisticated but small voltage regulator a couple of years ago. It is adjustable from about 2v up to 12v and tolerates amperage up to around 2 amps. You simply install it (just like the Runtz). Then adjust it with a tiny screwdriver so that your fuel gauge registers F when your tank is completely full and when you know your fuel gauge sending unit is working correctly and your gauge circuit is wired correctly and grounded correctly. And then you're done.
Also...Some have said the AD fuel gauge isn't any good. Some have said it was never accurate in the first place. In my experience it is actually a well-designed gauge capable of impressive accuracy and very long life. On the other hand the AD fuel gauge sender was designed to fail right from the start. It only had one wobbly pivot point and the case was made of cheap potmetal...which allowed it to wear out very rapidly. And when the case inevitably wore, the float arm would rub against the narrow sides of the tank. A bad recipe. Looking at it, I doubt any of the senders lasted more than 5 years. Some of you may recall I re-engineered the original sender adding an extra pivot point and making it work again.
Last edited by Peggy M; 12/06/2022 8:06 PM.
