6 Volt System or 12 Volt System?

Yesterday, I spent some time with my 1957 Century Resorter and started to ponder. I was told that the boat currently has a 6 volt system in it. Is it worth converting to a 12 volt system. In all honesty, I no longer get out on the water much. I’ve heard the 12 volts start easier, but really, I would rather work on the boat than float in it right now. Given my situation, would you convert to 12 volt or leave it a 6 volt boat? Thank you for your input.

1 Like

Yes!

Is that YES! change to 12 volt or YES! to keeping it 6 volt? As far as conversion to 12 volt goes, I have done some searching but have not found anything great, concerning what it takes to accomplish this task. If anyone has any info on where I might find a good source of info on this…preferably with pictures it would be much appreciated!

Yes do it. If your plan is to use the boat regularly . The 6 volt is fine and will work great, but 12 is better. You can make a 12 v look like a 6 volt if you like. That slow cranking stuff gets old!

Ok, 12 volt it is! Now all I have to do is find information on how to make the change. The search is posing a bit of a challenge.

I say convert to 12 volts. Without delving into Georg Ohm’s finer points of his law, there will always be voltage losses (voltage drop) in any circuits carrying current through a conductor. When you start off at 6 volts, even a 10% drop from battery to starter would mean the starter only sees 5.4 volts. If you start at 12 volts in the same scenario, the starter sees around 10.8 volts. This would give a lot more available cranking volts trying to turn over a cold engine. Also, lower voltage means higher amperage in the circuit necessitating larger cables for the starting circuit. I used to have a Chris Craft Sportsman with the 6 volt system. Keeping the battery cables as short as possible, I still used 1/0 gauge copper. At 12 volts I could have used a #2 gauge copper. You may also have some challenges in finding a 6 volt battery charger since 12 volt is so common.

1 Like

Thank you for the insight. I think I am going to convert to 12V.

12V brings the question to stay with the generator, or go to alternator. I don’t remember what engine you have, that would be a factor. Find a re-builder with an old guy there, youngsters nowadays don’t know what a generator is. They can usually rebuild your starter and generator to 12V. Make sure the generator is done to marine standards, (a spark screen) you don’t want a bunch of sparks in that engine compartment. You will need a 12V regulator also.

Things to take into account. I need to know this stuff. Thank you!

Converting to 12 V makes a lot of sense. Faster engine cranking certainly makes it easier to start. 12 V electronic ignition is more reliable than a 6 V system. Electronics modules. Don’t like to work below. 5 V. and it’s easy to pull a 6 V battery down that low in which case your spark will not be reliable. Adding accessories like bilge pumps and bilge blowers as easier as 12 V versions are more available. As for converting generators from 6 to 12 V it’s some thing we do on a regular basis. We change both the field coils and rewind the armature. It’s quite successful, and in most cases for small boats you can get by without the addition of an alternator.

1 Like

Thanks! Is there any other considerations? You mentioned upgrade bilge and blower units to 12V, but what about the various lights, the cigarette lighter and does 12v affect any of the dash gauges?

So that’s a good question. If you have an oil pressure gauge in your boat, it probably is a mechanical gauge so that does not matter. Your ammeter does not care whether you’re running on six or 12 V. It’s only measuring current. Your temperature gauge may need addressing. Some gauges have a capillary tube, which would be a solid heavy wire, going to the side of the cylinder head. If you have that again, the gauge wouldn’t care. If you have an electric gauge, there is a small voltage regulator that attaches to the back of the gauge. That would also be true for a gasoline gauge. Those are very simple devices to install. A cigarette lighter might cause a little more of a problem because they draw a fair amount of current and those voltage regulators would not be adequate. It would be possible to keep the knob and convert the cigarette lighter to a 12 V element.
The process is really quite simple and the only reason I can see not to do it is if you are shooting for 100% originality,. In general, they really aren’t any downsides.

Thank you for all the great information! I guess my next job is to find some one locally to rewind the generator armature! Thanks again!

I think most if not all 1957 Century boats had electric oil pressure and water temp gauges, if you do have factory electric gauges, Mark Clawson makes the step down resistors for your conversion.

1 Like

Thank you for the info!