DonaldSmith Posted June 19, 2014 Report Posted June 19, 2014 (edited) I've got two 6-volt batteries in series, to power my 12-volt pusher fan, in addition to the usual electronic stuff. Otherwise a small battery or battery pack would work fine for the 12-volt stuff. The main battery is positive ground and powers the starter, lights, radio, and other original stuff. A 6-volt positive ground alternator keeps this battery charged. The auxiliary battery is negative ground, so that I get 12 volts between the two batteries. i have isolated the ground of the power ports (formerly called cigarette lighter outlets). I have an old trouble light with a grounded shell. I had to wrap the shell with electric tape so that I wouldn't get a 6-volt short if it touched grounded metal on the car. I have to charge the auxiliary battery occasionally. My main battery is three years old and the auxiliary one is six. I may buy a new battery and use the three-year-old as the auxiliary battery and the six-year-old as the core to return. Edited June 19, 2014 by DonaldSmith Quote
Don Coatney Posted June 19, 2014 Report Posted June 19, 2014 battery I looked at first gives 12V for starting only & can't be used for 12V accessories. What reason was given for not using the battery for 12V accessories? Quote
Oldguy48 Posted June 19, 2014 Report Posted June 19, 2014 From what I have read, the radios don;t care about polarity. The humming you hear when you first turn one on is the vibrator, its job is to turn 6 V DC into an AC pattern so its swapping polarity when its on. They may not even be that fussy about input voltage. http://en.wikipedia.org/wiki/Vibrator_(electronic) The filaments in the vacuum tubes are designed for 6 volts. Applying 12 volts would likely cause them to fail, and the higher voltage in the B+ (vibrator) circuitry would upset the various voltage levels needed by the tubes to perform correctly. A good radio shop or savvy technician could make modifications to address those issues, but it would take time and money, and you'd still have an AM radio. Wayne Quote
Young Ed Posted June 20, 2014 Report Posted June 20, 2014 From what I have read, the radios don;t care about polarity. The humming you hear when you first turn one on is the vibrator, its job is to turn 6 V DC into an AC pattern so its swapping polarity when its on. They may not even be that fussy about input voltage. http://en.wikipedia.org/wiki/Vibrator_(electronic) Odd from what I've heard the radio is the only piece that does care about the polarity. Quote
Furylee2 Posted June 20, 2014 Report Posted June 20, 2014 Odd from what I've heard the radio is the only piece that does care about the polarity. A couple of years ago I had the radio in my 41 fixed (Model 800). Guy fought it for a few days, then remembered it was + ground. He had to re-order the vibrator, he got one for a – ground. After he switched it, it worked fine. Quote
DonaldSmith Posted June 20, 2014 Report Posted June 20, 2014 Among the generators listed in my DeSoto shop manual are three "For negative ground 2-Way Radio", one 45-amp and two 50-amp. So polarity was critical. Quote
JDaniel64 Posted June 20, 2014 Report Posted June 20, 2014 The filaments in the vacuum tubes are designed for 6 volts. Applying 12 volts would likely cause them to fail, and the higher voltage in the B+ (vibrator) circuitry would upset the various voltage levels needed by the tubes to perform correctly. A good radio shop or savvy technician could make modifications to address those issues, but it would take time and money, and you'd still have an AM radio. Wayne Yup yup, 12vdc would definitely fry the tube heater filaments and cause the 6v vibrator to fail with increased arcing in the contacts along with almost doubling its operating frequency. The Mopar 813 radio has an output voltage of 250vdc at the rectifier, which would be doubled to 500vdc using 12v supply. You'd need a new transformer, vibrator, and to rewire the tubes filaments in series (of two) to get it working in 12vdc. Quote
1941Rick Posted June 20, 2014 Report Posted June 20, 2014 Unfortunately I have a hyd electrically shifted M6 semi automatic in my chrysler product. It has a solenoid and a and another part that runs on 6 volts. The downshifting involves momentary cutout of the coil and ignition system. This just does not work if 12 volts is used. The only way I can convert to 12 v is to change the trans to a newer 727 with a 12 v starter and custom made bellhousing to bolt it all togather. Way more money than I have. I will just put the 12 v battery in and isolate the system from the car and hook up my Radio and maybe a gps. Not sure how the M6 works......I have a R10 OD 6 volt and it is operating on 12 volts with no issues at all......Down shifting was set up the same, cutting out ignition momentarily. I have done away with that and have a downshift button on the gear shift knob. Quote
janan5243 Posted June 20, 2014 Author Report Posted June 20, 2014 Appreciate all replies & advice. Think I will go with 2 6V batteries in series. Convert car to negative ground. will use 6v charger for 2nd battery temporarily, the install 12V generator or alternator during winter. Regarding original radios, I spoke with two shops that do restorations. The stock radio didn't care about polarity but if changing vibrator to solid state must be correct polarity. one shop in Freeport, Long Island, NY does job for around $200.00 plus shipping if no major repairs are necessary. 2nd shop is in Texas. He was $180.00 for basic resto. He replaces all the paper covered capacitors & stuff that I have read should be replaced. He would also install modern electronics in stock shell. AM/FM MP3 capability & Bluetooth about $400.00. both plus shipping. I'm going to check with guy on L.I. to see if he replaces recommended parts also. Regarding original post, I think switching grounds would be smartest move. Only very savvy guy would notice it, if you worried about originality. Quote
martybose Posted June 20, 2014 Report Posted June 20, 2014 Odd from what I've heard the radio is the only piece that does care about the polarity. When I was still running 6V a long time ago I installed a 6V negative ground alternator. All I changed was switching the leads on my ammeter and coil, and the rebuilt OEM radio worked just fine with a negative ground. I was told that it was only an issue if you had an electronic vibrator instead of the stock mechanical one. Marty Quote
janan5243 Posted June 21, 2014 Author Report Posted June 21, 2014 Some members mentioned using Optima 6V red top batteries. Could you post the model # of the one you have. They make a narrow one with 800 CCA. 2of those would fit side by side in the battery tray easily. There's an online site that has them for $112.80 w/free shipping. Mod. # 8010-044 Quote
janan5243 Posted June 24, 2014 Author Report Posted June 24, 2014 The online site is Streetside auto. I saw them on Amazon but some reviews stated that Optima wouldn't honor the Warranty unless you bought them from an authorized distributer. This site would honor warranty. I would pay shipping back to them but they ship replacement battery free. The price is $112.59 w/free shipping. Quote
janan5243 Posted June 27, 2014 Author Report Posted June 27, 2014 will my wipers & clock still work if I change from + to -- grd? Or will I have to reverse wires on them ? Quote
Plymouthy Adams Posted June 27, 2014 Report Posted June 27, 2014 wipers are non permanent magnet motor....polarity not a problem..the clock is just an electromagnet coil that energizes momentarily..also not a polarity issue.. Quote
rusty_apache Posted June 27, 2014 Report Posted June 27, 2014 I would toss a 12v battery in the trunk, a $13 Harbor Freight solar battery charger on the shelf under the back glass, and call it a day... Quote
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