Any know wher I can get a 12volt to 6 volt transformer......
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For an 50yr old car that i'm thinking of rebuilding, it's currently 6v, but I would like to rewire it to 12volt, but some of the equipment cannot be replaced due to being too rare, so therefore i'd need to run a dual voltage system...... could be a tad complicated, but it must be do-able, manily the charging, starting, lighting and convenince things that need to be 12volt......
Ron.
Ron.
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you could do it with a big **** resistor. What bits are 6v?
forgot to say.... 2 x 6v batteries should sit in the space you have and if you size them correctly should give you enough cranking amps. I saw a guy the other day with a 2.0L turbo westfield - the battery ( 12V ) was tiny in comparison to the normal ones.
forgot to say.... 2 x 6v batteries should sit in the space you have and if you size them correctly should give you enough cranking amps. I saw a guy the other day with a 2.0L turbo westfield - the battery ( 12V ) was tiny in comparison to the normal ones.
Last edited by mj; 15 February 2005 at 09:17 PM.
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There's the problem, the original 6v battery is quite big, the engine is an old 3.6 ltr flathead V8! the original wiring is falling apart, and there's not a single fuse in the car!! there are lote of bi-metalic strips though! wipers, heater blower, and ignition may not be able to be changed to 12volt!
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any big meaty loads will mean you have to have a dobber of a power supply/ trannie = bulky/ expensive. 2 x 6v batteries will give you 2 big dobbing power supplies, for the 12v circuit you are just using them both at once.
I cant say I know much about auto electrics, I had a quick look at RS, there doesent seem to be anything to suit.
what voltage is the alternator?
I cant say I know much about auto electrics, I had a quick look at RS, there doesent seem to be anything to suit.
what voltage is the alternator?
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yuuuhuh!
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one battery link too many
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RON - ignore anything I post about batteries from now on
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There is no alternator, it has a dynamo!! i would change that to 12 volt aswell........ it's a massive job though, the car has more switches and things than a supercar of today......... gulp!
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ajm's diagram is correct, that'll do the job.
The scary thing is, when i first looked at the original picture i couldn't see anything wrong with it.
BTW, i'm an electronics engineer.
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Time for some sleep i think.
The scary thing is, when i first looked at the original picture i couldn't see anything wrong with it.
BTW, i'm an electronics engineer.
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Time for some sleep i think.
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What needs to be 6V? Do you have any idea how much power is required?
I think you'd be better off with a conventional 12V battery and a DC/DC converter to power your 6V accessories. You could even run a separate 6V battery and charge it from the mains in between journeys - presumably the car isn't going to get all that much use.
I think you'd be better off with a conventional 12V battery and a DC/DC converter to power your 6V accessories. You could even run a separate 6V battery and charge it from the mains in between journeys - presumably the car isn't going to get all that much use.
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the first diagram does indeed show about the best way to destroy a pair of lead-acid batteries in a cloud of acid vapour and steam. Not a good idea
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I hereby promise never to offer electrical *advice* after booze again.
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shocking
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Originally Posted by mj
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I hereby promise never to offer electrical *advice* after booze again.
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shocking
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There's a place called CPC Batteries in Twickenham (google says phone 020 8898 6972) which I used when I had the dutton. It had a tiny battery compartment, and kept killing the new batteries I kept putting in. When I went there I said I need a battery that starts a Ford Kent engine and fits these dimensions. Turns out a Kent needs a lot of cranking power and the Mini batteries I was buying off the shelf just couldn't handle it!!
Chap looked up the requirements on a chart, found an appropriate battery and sold it to me at a respectable price. I never needed another one.
They've always stuck in my mind as a useful place to know, after that
Chap looked up the requirements on a chart, found an appropriate battery and sold it to me at a respectable price. I never needed another one.
They've always stuck in my mind as a useful place to know, after that
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wouldnt it be less hassle to lob a 12 volt battery in and take a feed to all the circuits requiring 12 v then take another feed to a 6v or variable voltage transformer (clairtronic sell these)to power the 6v circuits. on your diagram there you have a wire connected straight from live to neutral still.
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You can't transform dc, you need a switched mode PSU or dc/dc converter to produce a steady 6V from a 12V supply. You also need to know how much power will be required from the 6V supply before you can choose an appropriate converter.
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Originally Posted by AndyC_772
You can't transform dc, you need a switched mode PSU or dc/dc converter to produce a steady 6V from a 12V supply. You also need to know how much power will be required from the 6V supply before you can choose an appropriate converter.
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It should be perfectly possibly with current DC-DC converters but they are usually made to power computers & electronics rather than motors etc. so tend to give 3.3 or 5v DC outputs.
You may be able to use a much simpler solution if the current requirement is less than 5A. A 7805 Voltage regulator, with a couple of diodes will give you a 6v output at 1-2A depending on the model and a suitable heatsink. This little baby http://www.farnell.com/datasheets/55775.pdf can handle larger currents up to 5A and they cost 78p each.
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What type of car is it? Is it negative earth already?
Last edited by CharlieWhiskey; 16 February 2005 at 08:46 PM.
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You can't transform dc, you need a switched mode PSU or dc/dc converter to produce a steady 6V from a 12V supply. You also need to know how much power will be required from the 6V supply before you can choose an appropriate converter.
I knew that, that's why I suggested 2 batteries.
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