6-Volts to 42-Volts: Progress in an Electric World

My, how electrical systems for internal combustion engines have changed in the last century. Of course, we all know electricity is a necessity, because it’s an electrical spark that ignites the gasoline that makes the motor run.

The very first automotive electrical system was fired by a magneto, a simple device that requires no battery. Simply stated, the engine spins a magnet inside a coil, which creates electricity. A contact breaker, or switch, controls the release of electricity to the spark plug, creating a spark to ignite the fuel making the piston(s) go up and down accordingly.

As a matter of fact, to this very day, piston-driven motors such as those found in lawnmowers, chainsaws, and snowblowers, to name a few, all have a magneto creating the spark that drives the engine. Magnetos are used on a variety of aircraft. A single-engine plane would have two magnetos, for safety and an extra power boost to save fuel.

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The magneto was introduced to automobiles in 1899, and was used on many vehicles until the early 1900’s, when electrical systems on vehicles began demanding more power to operate headlights, interior and tail/stop lights. I don’t know if you’ve seen the very old movies that show a man cranking an engine to get it started. Lots of broken arms in those days, and that’s when the 6-volt battery, a generator to keep it charged, starter, distributor, coil and other components became the norm.

I remember as a kid in high school, taking my date to a movie, the drug store for a soda, and then a few tender moments on a lonely country road, trying to get to know one another better. Note that “trying” is the operative word here. That’s my car in the picture, a 1939 Studebaker Commander. What a ride.

It was necessary to have the radio on of course, but there was a caveat. Radios in those days required vacuum tubes to create their sound, and they were very energy intensive. So, it was necessary to park on a fair-sized incline, just in case we listened to the radio too long and the battery ran down.

I parked on the incline so she wouldn’t have to push so hard to get the car rolling fast enough so I could “pop” the clutch to start the engine. And of course, she wouldn’t have to walk uphill after all that pushing.

After the war, the 1950’s saw advances in car technology, and more demand on the electrical system, so 6-volt batteries and generators were replaced by 12-volt systems and alternators. Little has changed in the past 50 years, except more demands are being placed on those same systems today.

Now, it looks like the 42-volt system is the next step, possibly within the next couple of years. Cars will have 36-volt batteries and 42-volt electric systems, which will be integral to the development of hybrid-electric and fuel-cell vehicles.

If you’re wondering about the necessity for greater voltage, maybe I can help a bit.

I liken the flow of electricity through wires to the flow of water through a pipe. There are similarities, and it helped me understand the process.

Let’s go back to the 6-volt battery. In electrical terms, a volt is the amount of “push” electrons are given to flow through a wire, better known as current flow, which is measured in amperes.

A 6-volt battery, then, would supply a finite number of amperes to operate a car’s electrical system.

If you had a pump that created six-pounds of pressure on water in a pipe, the water would flow through the pipe with enough force to power, let’s say, a water-wheel designed to carry out a process requiring that much energy.

Increasing the load on the water wheel beyond what the six-pound pump could produce, you’d need a larger water pump. It’s the same with electricity. A larger load requires a more powerful pump.

Today’s vehicles have pushed electrical systems to the max, and it’s time for a change. There are on-board computers to run, ear-splitting sound systems, seat warmers, heated steering wheels, power windows, seats, rear-view mirrors, heads-up displays, global positioning and whatever else they can think of to use power.

Factor in the new electric cars and we’re faced with electric power steering and brakes, electric heating and cooling units, and those batteries to keep charged and running, to name a few.

42-volt systems are complex, and the changeover will undoubtedly create confusion not only to the general public, but to technicians who may not fully understand electricity. The ones who do should be cherished and celebrated.

The day of the shade-tree mechanic is slowly coming to an end. Much the pity, I found it a lot of fun.

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