Select Page

In the early part of the 1900s, all cars had 6 volt electrical systems.  Back then a 6 volt system was perfectly capable of powering the starter, lights and other accessories that the cars and trucks of the time had in them. Things changed in the 1950s, though.

In the 1950s, the power accessory revolution. Things like power windows, power seats, power antennas, radios, air conditioning and other accessories all started to appear. Unfortunately, this caused a problem for engineers who were taxed with the task of designing an electrical system that could power all these accessories.

The solution came from General Motors who in 1954 offered the first 12 volt system in their Cadillac Series 62 models. The rest of the American car industry quickly followed suit and soon every passenger car and truck made had a 12 volt electrical system. The results were significant. Alfa Romeo of Patchogue, NY tells us that vehicles with 12 volt systems started faster and multiple accessories, like the radio and AC could be used at the same time.

Today, though, we may be at another watershed. As the number of automotive gadgets climbs, the industry is wondering what to do. Today’s cars offer a buffet of new electronic technology and the car engines themselves, which traditionally used little electrical power, now have lots of electrically powered components (power steering, power cams, etc.).

So, wouldn’t a simple solution be to just beef up the existing 12 volt system? Let’s do a little math and see how it all adds up. Take all the power consumed by all the electrical accessories in a new car-the power windows, the defroster, the heated seats-and the total will probably be between some 1.5 and 2.0 kilowatts of power needed. To supply 2.0 kilowatts of power, a standard alternator must be capable of churning out more than 140 amps. Not a problem, especially with the new water-cooled designs. But size up an alternator to feed the 3.0 kilowatts of power expected in cars built later this decade, and you’re looking at 200 amps. This is an entirely different matter because that’s becoming a really big alternator and the wiring that is capable of carrying 200 amps is extremely thick and expensive.

So, as any electrical technician will tell you, to drop the cable and alternator size issues, one simply needs to increase the voltage of the system. More volts means less amps are needed.  The number being thrown around currently is 36 volts. It has been calculated that 36 volt systems would be just about right to power the complex demands of today’s automobiles and provide plenty of reserve for the future.

That being said, the car companies are hesitant to switch to 36 volts because there are some downsides. For example, electrical components will corrode more quickly and potential arcing are two major reliability issues. Plus, many devices in an automobile just prefer fewer volts. Light-bulb filaments, for example, grow too long and flimsy if designed to handle more than 12 volts and smaller, low-amp electric motors must be wound with special extra-thin wire that increases cost.

So, today we have a wait-and-see going on. Several manufacturers are experimenting with 36 volt systems but none have decided to go into production yet.

Earthgarage – Greener Car. Fatter Wallet.