What effect of 12volt batt used on electrical system

Well, I had my first S120 Travelall in 1972. It was 6V Negative ground, OEM, when I got it. I converted it to 12V. I did not change the starter, which lasted for another 60,000 miles. I did not change the wiper motor, but the wipers ran faster, so I always used the low speed selection. Never had a problem. BTW, I intentionally did not change the light bulbs. The ones that did not burn out, when first connected to 12V, lasted for several thousand miles ( true "proof" test). I gradually replaced them all. I carried 12V replacement bulbs and just made the change as needed. The 6V head lights were spectacularly bright at 12V, but they still lasted nearly a year.

I did NOT change my gauges. They worked perfectly through the following 20 years while I put 250,000 miles on the vehicle. I did not change the coil for the first 30,000 miles. The coil never failed, but the points were subjected to too much current and burned up about every 1500 to 2000 miles until I installed two ballast resisters in series on it. The two resisters stopped the burned points, but the engine was more difficult to start. Eventually installed a 12V coil, which still required a ballast resister.

The S120 I have now was converted by the previous owner. He installed voltage converters for the gauges and apparently the wrong ohm rated fuel sending unit(s). The gauge only reads half full when tank(s) are full, and empty when there is still half full, (yes both a right and left tank installed by previous owner, a conversion I also made on my first S120)

A Question to all on this post, not to steal it but for info to all. Why did IHC Trucks use a step down voltage regulator on the gauges with 12 volt trucks in the late fifties early 60s with this unit. I am curiuos to get some opinons. Thanks
kevin

Prior to the mid fiftys the King Seeley gauges were fed 6 volts and had pulseing senders. A change was made in the mid fiftys to all King Seeley gauges (whether they were used on 6 or 12 volt) and they used a pulsed current limiter ahead of the gauge with a flat resistance type sender after the guage. This later system was used up to the end of the light-line and on Ford and Chry vehicles as well.
The pulsed current regulator was not needed on the earlyer system because that function was included in the sender itself. This made the senders more difficult to make and more expensive then a flat resistance type that was used later.
It should be noted the that the current limiter is NOT a voltage regulator. It will give a pulsed current that will adv at around 5 volts if read with a meter, but is a CURRENT limiting device. It has a resistance wire and bi metalic strip with a set of points that open and close.
You cannot mix the two systems, each has its own guage head and matching senders. You can replace the whole system (can fit newer gauge head, current limiter, and sender) to an older truck, but cannot use a newer (and more avaiable) senders on the old system and expect any accuracy. Nor can use the pulsed current limiter on older style guages and expect any accuracy ( in this case you have two pulsed devices that will be in conflict with eachother, one in the sender and one you added)

Info only, 1 of these units are listed in all 12 volt trucks, 1956 S series, I will be using this unit and have everything from a 180 gauge set, the correct term is regulator voltage asm. pictured below. I like the feedback on the 2 posts, dont know if I will go 12 volt this year or next, life is busy. Again info only

It is not a true voltage regulator in the sense that it does not give a constant output voltage, the output varys between input and a very low voltage that adv to around 5 volt. Many think that it provides a contant 5 volts, which it does not. Years ago before I knew how these operated I tried useing (aa then new device) a 5 volt IC regulator in place of one of these "regulators" and no amount of adjusting the output would make the gauges work correctly. There really isn't a correct term for what the things are, they are not a true voltage regulator, and not really a true current regulator, but there output is based more on currrent draw then voltage.