VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt 2 x 6 = 12

so maybe this is really dumb, but...

if I wanted to run a small 12v accessory, why couldn't or shouldn't I buy two small 6v batteries and wire them in series to get 12v when I need it...while charging each individually by having them in parallel with the car's 6v battery?..

what am I missing?..

epi

It will not work, because when ever you have the 12 volt accessory connected you will have 12 volts everywhere in your system, possibly causing smoke to escape. :eek:

I have learned that electricity is nothing more than smoke flowing inside the wires, and if you let the smoke out things stop working.

I would suggest if you want to use a "small 12 v accessory" you get a portable power pack (available in auto parts stores or sporting good shops). They are a small box with a handle and two jumper cable clamps coming out of it. I have one from B J's Wholesale Club, ($75.00). I can jump start a car, plug in a 12v accessory with a "lighter plug", it has a light for emergencys. Mine also has a 300 W inverter so I can run a laptop, or a small appliance on house current. These can be recharged by plugging it in at home with the supplied charger. Here is one from Aubuchon Hardware to give you an idea of what they look like.
battery pack
Dan.

k1dan,

thanks for the lesson in contained smoke...

the battery pack sounds too easy...I guess my scheme would only work if I had a switch where it would disconnect it from the car while providing 12v to the output terminal...so as not to let the genie out of the bottle...

epi

I like the booster battery to run 12v accessories on the 53, it also has an air compressor, a trouble light, two 12volt accessory jacks (cigarette lighter style) jumper cables and a 300 watt 110ac outlet just like Dan says, We charge it up at night in the motel room. It will run a Dremmel tool, a small electric drill and I have a set of Dixie air horns and a CB radio to use on tours. I think it is better than jerry rigging another 6volt battery and having to worry about the high pressure smoke getting loose, and they are spill proof, so far anyway! (IMHO)

Radio Shack used to sell a 12v to 6 v inverter I had one in an old vw to run the radio and cb for years

What you want to do with the 2 6 volt batteries should work fine providing you have a proper switchover arrangement wired up. You could not be charging the second battery at the same time you were using it for the 12 volt accessories though.

There is a way to do the 6 volt system and some 12 volt stuff with 2 six volt batterys in series and in parallel with out having the 12v come into your 6 volt items, however you will have to maintain all the 12 volt stuff above ground, otherwise you will have to isolate the 12 volt items from the chassis ground that your 6 volt items utilize. I have done the same thing to use 12v lights on a 36 volt golf cart.

Actually, the whole concept is much simpler than what a lot o fpeople belive.

The "Mysterious 12 volt to 6 volt converter" is nothing more than a resistor of about 2 Ohms resistance.

The 12 volt light on a 36 volt golf cart would not have to be isolated as long as the tapped voltage (IE battery post chosen) were 12 volts with respect to ground.

In the matter of 2 six volt batteries to power a 12 volt accessory can work, and can be tied to chassis ground if the car itself is a negative ground (assumes accesory is a 12 volt negative ground. NOTE: there were some Blaupunkt manufacture radios, and a few Japanese made radios that could be switched, or were a 12 volt positive ground.)

With all of that said, in light of the complexity of the relay wiring that would need to be made, it might be easier to buy or build what is called a "DC to DC" convertor, which is nothing more than the same type of circuit used for a DC to AC power invertor, incorporating an AC to DC 12 power supply.

Depending on power requirements for the accessory, one could construct a converter with a 6 volt vibrator, or a "Monostable Multivibrator" circuit. run it to a transformer of 1:2.5 turns ratio, and then into a bridge rectifier into "PI" filtering- add a voltage regulator, and you are done. The transformer will determine the final size of the package, but in most of the vehicles that had a 6 volt system, you should find plenty of room under the dash, or bury it in the trunk. Figure about the size of a football, or smaller. If you are running with a 6 volt negative ground- no one would be the wiser, as the unit's output negative could be tied to chassis ground- hence- one wire to run the radio, or other item(s).

The problem with the relays is that the one that would be required to switch the two six volt batteries alternately from parallel (for charging) and then to series for 12 volt usage would require an expensive contactor. plus it would look like Rube Goldberg got a hold of it.

About golf carts...nothing on a golf cart is "grounded to chassis". The entire system is a closed circuit.

Further research on my battery pack. I was able to run my laptop from the built in inverter for over two hours with moderate usage as a Packet Radio terminal.
The adaptor for the Laptop indicates 75 Watts max.

Dan.

Was just browsing the Filling Station online catalog and came across a 6 to 12 volt converter. No picture but I'm sure it would easily mount behind the dash. Part number CAS-1 and $89.

K1 Dan, ( This is worth saying again....) I think... I have used my Vector Booster, 300 watt AC converter (it can be detached and used in any 12 volt supply), air compressor, work light and 12vdc supply to power a CB, a set of Dixie air horns, a Dremmel tool, drill and several other 12 vdc tools and then just charge it up in the motel room for a couple of hours. The air compressor is very handy for airing up tires and blowing out fuel lines. It does a real fine job of powering the CB all day without the noise that ignitions usually cause. I have had it three years and it only cost about $80.
I used an old extension cord and a cigarette lighter plug to make a accessory connector with a switch for the dixie horns and the CB I just used some bayonet connectors to plug in the battery pac, the dixie horns and the CB, then I sit the battery pac in the rear floor-board, run the wire under the front seat and to the small plastic console that you use for a drink holder, cassetee holder, etc. that is where I mounted the switch. The cigarette lighter plug can be quickly removed to use the booster, air compressor and trouble light. It is the cat's meow as far I am concerned for touring with our old cars!

mrmack,

can you recommend a website where I can go to look at this vector booster?..

I'm not saying I'm giving up on 2x6=12, as all the fellows here have given good insight into this rube goldberg adventure...

however, your vector booster sounds good, too...

thanks,

epi

The comments on this subject are amazing. It depends on what you want to use the 12 volts for but I observed an installation recently that was economical and simple.
I am going to install a FM converter on an AM radio. The car is of course 6 volts and the converter is 12 volts. I plan to buy a 12 volt dry cell battery (the type used for electric fence, etc)install it in the trunk and have 12volts just for the converter. It will work and no more than I will use the FM it will last for a long time.
good luck JIM

I got the booster from SAM'S Wholesale Club, they do have a website, most discount home and auto centers sell several different ones from a single feature to multi-function ones.

I think we may have scared the original poster away.

My description, while intended as a technical shortcut is best described as combining the power inverter (Tripp Lite, 300Watt for example) to a 12 volt power supply( Say a Radio Shack 12 volt regulated supply, or a Tripp-Lite PR-3 for example). But in the interest in reducing losses, and minimizing space, I simplified it by describing a circuit that rather than boosts to 120 volts and then back down to twelve, it just boosts to 12 volts. DC to DC converters are manufactured, and could be utilized too, but costs start to figure in, and Tripp-lite only makes 12 volt to 12 volt invertors, not any 6 volt to 120 volt invertors.

For a hard wired system, the one I described is the most convenient in the long run. The hassle is in the begining, and some people just do not want to start dealing with that aspect of electronics. Most of the other solutions, which do work, result in a demonstration of the different levels of inconvenience that people accept on top of the inconveniences that some old cars can present at times.

A double relay system would work, to charge a pair of 6 volt batteries and then allow for 12 volt operation, but that reults in a lot of aditional wiring, even though you can still utilize the chassis ground as one set of wires up to a point. The relays themselves present their own concerns if contacts fuse, or if the contacts are burned. Not to mention the eyes crossing when or if you ever needed to trace the circuit again in the future.

In total seriousness, I would consider producing 6 volt to 12 volt power invertors myself if I knew there were a market, or if enough people showed interest to the point where any testing and design costs are defrayed enough so that I could see some degree of compensation for my time spent putting them together. The real cost would lie in the transformer.

odd parts,

nope, I'm still here...soaking in all of the great ideas being posted here and mulling my options on my kooky idea...

thanks,

epi

Depending on the amount of amps that you need look into a 6v-12v INVERTER.I used to use one to power my CB in the 6V cars.They increase 6 v to 12V.Now I use a booster pac and it will power a CB for a week plus you have a emergency jumper with you.I guess it all depends on what you want to run off from it.

I have seen the inverters used they are commonaly in 10 amp or 6 amp versions, but, the main thing I wanted to get away from was having to have the 6 volt generator have to power any extra stuff, it works just jim-dandy with the original accessories, but I don't want the old girl to be over worked , therefore the idea of the independant 12vdc supply for the CB and any novelty item I may have, the booster pac took care of that nicely and a big plus is having a handy-dandy 110 va/c outlet, a light and a very useful cordless air compressor, it beats a tire pump all to blazes!

I guess I'm a little late reading this thread but the first thing that came to mind for me was something like this:



Of course you would throw the switch up to charge and down to use 12V accessories. Probably want the switch in neutral for starting the car depending on the size of the wiring used.

-R

Don't overlook the root problem presented here ,running a 12 volt accessory from a vehicle with a 6 volt system. When you convert from 6 volts to 12 volts you will require twice the amperage from your system as the 12 volt accessory demands, a 10 amp 12 volt accessory will require an input from the six volt system of 20 amps in order to get the wattage required to power the 12 volt accessory, that quickly overloads the six volt chargeing system and is a death sentence for the old generator. Therefore my argument for the 12 volt booster battery, completely apart from the cars electrical system is the best way to go to power your 12 volt accessory, whether it be a CB, CD player or other 12 volt accessorys of medium power requirements. When you need to power anything larger like an A/C system consider going to a more modern car, like a 1965 up with a high capacity alternator charging device (IMHO) or converting the car to 12 volts and a single wire alternator of ample charging capacity

Point taken. However, if you examine my circuit, I am not converting 6 to 12 volts. I am adding 6 volts to the six volt system supplied by the car via series connection. Therefore, the car battery supplies 1X the current required by the 12V device not 2X. Assuming this battery is smaller, it will go flat before the car battery especially if the engine is running and keeping a charge on the car battery. At that time, you turn off your 12V accessories, throw the switch up, and charge your supplemental battery.

Cheers,
-R

Correct RF ,However you can only use a % of the energy you put in, some is lost in the charging and discharging of the batteries,The same old low output generator will have to replace the power you drained out but it will have to do two batteries at one time instead of the one,also your two batteries will maintain a level voltage between them and will both go flat at the same time if hooked in series, but you can use a battery charger to recharge at night, That is what those of us that use the 12 volt boosters do and they also have built in chargers, that will either charge the battery from 12 volt (I use my tow vehicle's 12 system to charge it) and also a 110Vac charger for use in the motel, you pay for the electricity used in your room anyway, that is if you use motels!.

I once had a 12 volt 1960s Delco AM-FM radio in my 1932 Chevrolet. I had a 6 volt motorcycle battery in series with the + to the radio. It worked ok and did not affect the rest of the electrical system. All I had to do was remove the motorcycle battery and recharge it after a few days.

I did that with my Dixie horns as a test and they worked ok, I never used them very steady, like a radio or CB. I kept them above ground, but probably didn't need to.