6 v neg + 6 v neg = 12 v?

[DonaldSmith]

My 47 DeSoto is running happily on its 6 volt positive setup. Leave well enough alone? But- my son got me a Garmin, which works on 12 volts, not to mention other modern accessories. (I can't think of any, so I won't mention them.) Am I really going to drive the DeSoto far enough that I would need the Garmin? Never mind. We don't have to be practical to play mind games.

I have a spare 6 volt battery to play with. What if? What if? If I converted the car to 6 volt negative ground, I could add the other 6 volt battery in series, to get 12 volts negative ground, for the Garmin, etc. The 12 volt circuit would share the same negative ground. The starter, lights, etc. would remain 6 volts. I would have to trickle charge the second battery occasionally, depending on usage.

What to change?

Reverse the gas gauge wires and the ammeter wires.

Starters, wiper motors and fans don't care about the polarity. Something about how the motor is wound determines its direction.

The radio? I checked the circuitry on my Colonial 602, and I didn't see any diodes in the 6-volt circuit. The high voltage circuit is negative ground anyway. (I found that out when I blew out some large capacitors, thinking that they should be positive ground.)

I remember reading that Chrysler provided police cars in negative ground because that's what the Motorola radios took. Those radios must have been polarity sensitive.

The charging circut? Hmm... Does the generator's output polarity depend on the polarity of the field circuit? (the thin green wire at the generator) Does the regulator care what the polarity it is?

Does the coil care?

Has anyone changed the polarity while maintining 6 volts? What does it take?

[Merle Coggins]

I think you'd be better off installing a 6volt to 12 volt converter. I got one from Meyers Electronics http://www.pressenter.com/~cmeyer/ And although I haven't installed it yet, I plan to hook it up to a 12 volt power outlet (cigerette lighter socket) so that I can plug in my GPS, a cell phone, or etc.

I think you're asking for problems if you attempt what you have in mind.

Merle

[greg g]

why not use a 12 V jumper pack? they usually have a cigarette lighter type acc plug. Mine will run a radio about a week on a full charge. It would probably run bitchin betty (recalculating, make the nearest safe U turn) for a good long time. Jus tneed to charge it overnight for those long road trips. a splitter and your cell phone/cd player is in business also.

[Normspeed]

I have the Meyers converter and I'm real happy with it. I rigged up a triple cigarette lighter plug so I can plug in my XM radio, an LED map light, etc. The Meyer unit can handle up to 6 amps at 12V neg ground while the original system remains 6V pos ground.

[Don Coatney]

I have driven several miles using my GPS on its own battery. Not sure how long it will last on its own but my guess is several hundred miles. However Gregs suggestion is the best. Get a 12 volt battery pack and drive away.

[Dennis_MN]

The referenced thread contains the source of my little -6 to +12 inverter.

Works like a charm for my GPS (speedometer) and the radio.

http://www430.pair.com/p15d24/mopar_...light=inverter

By the way, the twist locks were just temporary and are now soldered.

Dennis Sullivan

[123.gramps]

Morning Guys! I have a 48 that a previous owner converted to neg ground. Cause mush confusion, but...changed wires on ammeter and coil. Don't know what else was done, but runs great, charg system works fine. Long time ago I fixed my daughters old VW up w/2 6v batts in series. Worked fine.

[James_Douglas]

Don,

Don't waste the time and effort. I have a friend who just got a Garmin GPS and he purchased one of those tote battery packs to use in his 6 volt Cars. Just stick it under the seat.

The tote has a battery in it and a mini AC charger. You just plug it in a night at home or in a hotel room and it is ready in the AM.

He used it for a week and v=never came close to running it down.

Cheaper, quicker, and works...

James

[wayfarerstranger]

where can you buy one like that on your firewall ?? thanx

[Dennis_MN]

where can you buy one like that on your firewall ?? thanx

I used this source and paid about $55 for it. I've since added a switch to shut it off during winter storage.

http://www.rgclassictunes.com/