6 volts DC to 12 volts DC

[Don W/Norfolk]

I'd like to install a couple of 12 volt dc items to my recently acquired '41 pickup running a 6 volt electrical system.
The additions are low load LEDs, a tachometer and a clock.
How is the best way to accomplish and what items do I need?
dw

[tubman]

It's a little more complicated than one would initially think. Amazon has many devices that will bump 6 volts to 12 volts no problem. They are not expensive, and cost depends on capacity (watts). With that bridge crossed, you still have to deal with dirty power and polarity. Most modern devices have plastic cases, so dealing with polarity is a simple matter of being careful when mounting the devices and "crossing the wires" when hooking them up. I have found that most modern devices (disc players etc.) will handle "dirty" power quite well. If they won't, you're on your own. We marketed a device several years ago that boosted the power to an accurate "clean" 12 volts, as well as changed the polarity. We found there was no market for it at anything above Amazon pricing, so we gave up on the venture.
"Low load" LED's are probably good (unless they are of the wrong polarity; most LED's are polarity sensitive). It is mainly up to you to choose compatible devices. Just about anything you buy these days are very low draw, so that shouldn't be a problem.

Tachometers are a whole other story. About 10 years ago, I had the mistaken idea that there was a significant demand for 6 volt tachometers, so I worked with a friend of mine who was an experienced EE to make a simple device to raise the voltage and change the polarity of the power driving the tach logic circuit. It wasn't that simple.

To make a long story short, you have to have a device that :

1. Raises the voltage and changes the polarity to the tach logic.

2. Raises the voltage and changes the polarity of the signal from the distributor.

3. Has added circuitry to filter out the dirty power supplied by older automotive electrical systems.

We were able to do this, but we ended up with a device that cost us (in quantities of 10) about $150 each. We priced the first batch of 10 at cost, and sold them out almost immediately. We made a second run of 10, and found that we had saturated the market at this price. I ended up keeping two for myself (one on my car and one on my engine test stand) and ended up selling the rest at $120 each. We realized that there was no money to be made and moved on.

For proof, here's a video of our device on my engine test stand :https://youtu.be/TaxpuDkWAqc.

[Scott52]

I put a 6V tach on my Power Wagon

[RalphG]

The old six volt systems were positive ground and that is a big problem when plugging in any modern device. Some of them do not survive.

[petehoovie]

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Originally Posted by Scott52

I put a 6V tach on my Power Wagon