TheSamba.com :: View topic - anyone tried dual 6v batteries to power 12v??

Sun Dec 03, 2006 10:21 pm

i was wondering if ayone had tried running 2 6v bateries in series in a 6v car to keep it stock and have a 12v radio too without converting the car to 12v system?? I would like to figure out how to do this. either a 12v porsche generator with two 6v batteries in series , or some kin of battery isolater. any ideas?? i would like to keep the car all stock 6v electrics sapphire radio included, however, i want to put a 12v radio under the seat and use relays from the headligt plugs with 12v to put h4 12v headlights in. other then that, i want all 6v, and done in such a way as its easily removable from the car. i need help with this one!!!

Sun Dec 03, 2006 10:42 pm

I don't think it works that way....but nice idea. :lol:

Mon Dec 04, 2006 12:39 am

why not it works with 2 small 6v batteries?

Mon Dec 04, 2006 2:50 am

my old 63 MGB had originally 2 x 6 volt batteries under the rear seat. i can't magine any reason why it wouldn't work on a bug.

Mon Dec 04, 2006 4:45 am

Yes it would work... It's all in how you wire it up... Charging both battery's from a 6v. generator is the sticker...

Mon Dec 04, 2006 5:46 am

I don't think it can be done. You can have one or the other. You can't have 6v going in and 12v coming out.
You could have a voltage drop for everything 6v but that wouldn't be cost effective.

Mon Dec 04, 2006 6:36 am

Connect the 2 batteries together in parallel, + to +, - to -, and run your 12 volt accessories off of the batteries in series. I think that will work. Or, I have wondered if you can use a 1:2 step up transformer on a 6 volt battery. If you can you could find the transformer at RadioShack.

Mon Dec 04, 2006 11:07 am

You could wire the batteries in parallel (+ to + / - to -), but it may place to much draw on a 30A 6V generator, plus when you go to wire the battery in series to make 12V you would create a dead short to ground. You could install 2 6V batteries in series to make 12V, convert to a 12V generator / alternator to charge the two batteries, and then drive the 6V items off of a single 6V battery and the 12V items off of both batteries. The other option would be to get a DC-DC converter to make 12V from the 6V battery(s), but it would be pricey for one that could provide enough amperage to drive a car stereo.

Mon Dec 04, 2006 12:10 pm

Years ago I purchased a US manufactured switch by "Orpin" from (of all places) JC Whitney. It was a 6 volt-12 volt switch. I still have it installed and use it daily on my '65. Basically, I have two 6 volt batteries connected to the switch. It is wired such that when you turn the ignition key, it draws 12 volts (6+6 in series) to spin the 6 volt starter like a whirlwind. Release the key and the switch puts the two batteries into a parallel mode and everything runs on 6 volts and the generator charges the two batteries in a parallel but isolated manner. That is, the failure of one battery won't affect the other.

For running an individual component on 12 volts (Like a radio) I use an old Archer (radio shack) voltage converter. It takes in 6 volts and puts out 12. The Archer units are no longer manufactured but there are modern equivalents. Try a google on "6 volt to 12 volt". The Archer is limited to a 3 amp load as I recall, so it might not be robust enough to run a big stereo system.

Full conversion to a 12 volt system is on my long list of things to do....

Recreation vehicles have battery isolaters to charge 2 (or more) 12 volt batteries and then run items on 24. You might want to search the RV sites.

Good luck.

Mon Dec 04, 2006 12:33 pm

I can't imagine why you would want to do this.
Quote: either a 12v porsche generator with two 6v batteries in series , or some kin of battery isolater.
If you switched to the Porsche altenator, then that would no longer be stock. If it is a valuable car, then I would only drive it occassionally and wouldn't be worried with a 12VDC radio. If it's a driver, then I would do a proper 12 volt conversion and keep the OG radio for looks only. I wouldn't think that it would take too much away from the value of the car. Just keep all the 6-volt stuff if you wanted to go back.

Otherwise, I went to school with a guy that drove a 6-volt Desoto. He had a 12-volt deep cycle battery in the trunk to power the stereo. He charged it overnight every few days.

Mon Dec 04, 2006 2:12 pm

Convert to 12 volt, and drop the wiper and radio with a voltage reducer. Seems like you want a 12 volt radio and headlights. Those are the two primary reasons to convert anyway. Keep all your 6 volt parts and switch back when you want to go stock again. Jut my 2 cents by the way, i'm no expert, but going with dual 6 volts and doing all the converting just seems like a waste of time and $$$ when you can buy a conversion kit for cheap.

Tue Dec 05, 2006 12:08 am

joeljohn001 wrote: You could wire the batteries in parallel (+ to + / - to -), but it may place to much draw on a 30A 6V generator, plus when you go to wire the battery in series to make 12V you would create a dead short to ground. You could install 2 6V batteries in series to make 12V, convert to a 12V generator / alternator to charge the two batteries, and then drive the 6V items off of a single 6V battery and the 12V items off of both batteries. The other option would be to get a DC-DC converter to make 12V from the 6V battery(s), but it would be pricey for one that could provide enough amperage to drive a car stereo.

You've got good and bad advise here.... NO offense intended. You won't be able to run the 6 volt items off of one of the batteries. I had a similar problem and tried this when I had my BJ42 Landcruiser. It was 24 volt and I tried the same thing to run a stereo. The problem arises with the charging end of things. Since one battery is being drained the system tries to charge it. Unfortunately the other battery isn't being drained and then gets BOILED! Go with the Battery Isolator system. They are easy to come by.

Tue Dec 05, 2006 6:02 am

L572 wrote: Recreation vehicles have battery isolaters to charge 2 (or more) 12 volt batteries and then run items on 24. You might want to search the RV sites.

That's not why RVs run battery isolators. They run multiple batteries to have a higher power reserve and higher cranking amps.

In my semi-tractor, I run 4 deep cycle industrial batteries, wired parallel. This increases amperage and yields a longer power reserve, but still only produces 12 volts.

Tue Dec 05, 2006 10:24 am

don3751 wrote:
That's not why RVs run battery isolators. They run multiple batteries to have a higher power reserve and higher cranking amps.....

sorry....my mistake..... :oops: I really need to stay away from theorizing.... :oops: :oops:

Tue Dec 05, 2006 11:58 am

Why go to all the trouble ? I converted the car(s) to 12 volts, used a replacement 12v wiper armeture and a 12v Saphire V radio and installed the Saphire I's face plate & dial lens on it. I mounted the 12v regulator on the top of the generator too.

Tue Jan 09, 2007 11:02 pm

i want to do this so under the hood and everywhere else is bone stock. i want a hidden stereo under my seat and bright headlights. i want the original radio to function on its own with its 1 dash speaker. i dont mind if undei. hr the back seat isnt stock. this is a rare 58 i year only color convertible, i want it nice anc stock , and will be driving it a lot, thats why i bought it. i hate trailer queens. i want to be as stock as possible, but i will go crazy with only AM radio and dim headlights on the freeway. if my high beams are on its ok. and i dont need a big stereo, just a 60w headunit with 2 speakers under the seat that can easily be removed at the shows.

Thu Jan 11, 2007 2:10 am

If simpllicity is what you are after. Do what you feel you need to to get the 12v system. Don't bother with a second "hidden" head unit. Put in an amp and speakers; then run it off an Ipod or like. Seen it alot lately and it's great as there is nothing to worry about. the Ipod fits in your pocket and the rest is bolted in.

Thu Jan 11, 2007 3:37 am

Go here: http://www.shoptalkforums.com/viewtopic.php?t=9886...highlight=

Thu Jan 11, 2007 7:55 am

as it's been said before, take a look at what you want and work backwards from there. if you want it "original", enjoy the dim glow of the headlights, the AM of the saphire and pack a boom-box. if you want custom bright headlights and a 12V stereo then there's likely a few ways to go. the easiest, i think (and i've done it) is to swap your 6V generator for a small diameter 12V porsche generator (again, as previously mentioned) which is the same physical size and hard to tell apart from the 6V unit (you can also get the genuine VW 6V unit rewound for 12V -- there was a guy at HVWdragdays a few years ago sellign them) -- it's literally nearly a direct swap. crafty folks have even installed a dummy 6V-vreg on the top of the genny (for looks) with a hidden 12V-vreg under the rear seat. trouble is, these gennies only put out 25amps -- not really enough amperage to run a high-powered amp and halogen headlights at the same time -- you'll burn out your genny (ask me how i know, then ask me 5 more times). if you keep the 12V stereo small (less than 50 watts), you can make it work (use a 10A fuse on the amp/radio power lead just in case -- a fuse is cheaper than a toasted genny). the ipod/amp combo is a teriffic way to get sound in an old bug and there's plenty of posts on this (or PM more for specs on my set-up -- i even have 2 small stereo speakers wired in the original dash location... not true stereo because of the placement, but it's a pretty bumpin' system for being completely invisible). after the 12V conversion, you'll swap your lights (which you want to do anyway), coil, wiper motor (or use a v-drop) , and have rich langenwalter convert your saphire to 12V (or use a v-drop). the hardest part is the starter motor and tranny. your original starter will run for a few years on the 12V current (being careful -- it's a powerful kick), but this is the only swap that really takes sweat and time (again, lots of posts) -- everything else can be done in an afternoon with minimal knuckle scrapes. and if you wanted to "swap it back" (which you'll honestly never really want to do), it could be done in an afternoon as well -- or in as much time as the untested dual 6V battery idea, especially considering the brainstorming time it'd take to make it work. have fun.

Thu Jan 11, 2007 11:15 pm

hlwimmer wrote: as it's been said before, take a look at what you want and work backwards from there. if you want it "original", enjoy the dim glow of the headlights, the AM of the saphire and pack a boom-box. if you want custom bright headlights and a 12V stereo then there's likely a few ways to go. the easiest, i think (and i've done it) is to swap your 6V generator for a small diameter 12V porsche generator (again, as previously mentioned) which is the same physical size and hard to tell apart from the 6V unit (you can also get the genuine VW 6V unit rewound for 12V -- there was a guy at HVWdragdays a few years ago sellign them) -- it's literally nearly a direct swap. crafty folks have even installed a dummy 6V-vreg on the top of the genny (for looks) with a hidden 12V-vreg under the rear seat. trouble is, these gennies only put out 25amps -- not really enough amperage to run a high-powered amp and halogen headlights at the same time -- you'll burn out your genny (ask me how i know, then ask me 5 more times). if you keep the 12V stereo small (less than 50 watts), you can make it work (use a 10A fuse on the amp/radio power lead just in case -- a fuse is cheaper than a toasted genny). the ipod/amp combo is a teriffic way to get sound in an old bug and there's plenty of posts on this (or PM more for specs on my set-up -- i even have 2 small stereo speakers wired in the original dash location... not true stereo because of the placement, but it's a pretty bumpin' system for being completely invisible). after the 12V conversion, you'll swap your lights (which you want to do anyway), coil, wiper motor (or use a v-drop) , and have rich langenwalter convert your saphire to 12V (or use a v-drop). the hardest part is the starter motor and tranny. your original starter will run for a few years on the 12V current (being careful -- it's a powerful kick), but this is the only swap that really takes sweat and time (again, lots of posts) -- everything else can be done in an afternoon with minimal knuckle scrapes. and if you wanted to "swap it back" (which you'll honestly never really want to do), it could be done in an afternoon as well -- or in as much time as the untested dual 6V battery idea, especially considering the brainstorming time it'd take to make it work. have fun.

What he said!!!! He's packed all the information into one post. Well done!
In the end it's your car so do what you like. My '64 is still running on 6V. I don't see a reason to change it as I only use it for bombing around town. If I did alot of highway running I'd consider the conversion but for me it just isn't worth it.