12vdc to 6vdc Constant Voltage Regulator

[Stringy]

Looking for a 12vdc to 6vdc Constant Voltage Regulator!

Just been looking for a Vintage Car Forum in OZ, but no luck so will ask here!

I have a timber ski boat built in the late 50's, which I am rebuilding. The electrical system is 6v. I am converting to 12v to run the mallory ignition and starter. All of my gauges are 6v which I am keeping. I have been told that a 12vdc to 6vdc Constant Voltage Regulator is the way to go, but can't find one in Australia!

[watson]

G'day Stringy,
Have you tried the electronic sites like Jaycar or Altronics or maybe Oatley electronics?

[Wood Borer]

It will depend on how much current your instuments draw.

If there are globes in the instuments for night time, it would pay to run the globes off 12V (after replacing them with 12V globes) and just running the instruments on 6V using this regulator from Dick Smith. It is only a 1A regulator but it might be OK. If not, use one for each instument. At $1.20 each it won't break the budget.

6V Regulator from DSE (http://www.dse.com.au/cgi-bin/dse.storefront/4826990109c3ef962740c0a87f9c06f1/Product/View/Z6549)

[scanfor]

This one will do up to 1.5A which should be enough for your gauges.

http://jaycar.com.au/productView.asp?ID=AA0218&CATID=&keywords=converter&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

[Stringy]

Tried Jaycar in Newcastle a few weeks ago and due to me not knowing "exactly" what to ask for, had no luck!

Scanfor, the adjustable dc to dc converter looks the go
are these true CVR's & not choppers (I have been on the flathead ford site and they discourage the use of choppers).

I have the following gauges;
2 water temp (one for either side of the block)
speed/knots
Oil
Amps

Is there a way that i can tell how many amps the gauges draw?

Good idea about running the gauge lights on 12v. It looks like the gauges had never run bulbs but have the provision for them. It's a ski boat so has no navigation lights either!

[Wood Borer]

If it hasn't got it written on them, you may need to measure the current using a multimeter with a suitable current range in series with each gauge.

I suspect that you will be OK. For the cheap price of the regulators, you could hook them up in a temporary fashion to see if they work. they generally have over current and thermal shutdown.

[Wood Borer]

Another solution to your problem is to use two 6V batteries in series to give you the 12V and then tap off 6V from one battery for your instruments.

No regulators and no worries about if the regulator can handle the current.

[Stringy]

One of the suggestions on the US flathead ford site was to use a centre tap battery. Had a search for one in OZ but could'nt find one, two 6v's are exactly the same thing only in 2 seperate cases ay! Nice deduction Watson, no, Wood Borer:2tsup:!

[scanfor]

Stringy

Not sure about them being "choppers". I suspect that they are just a Voltage Regulator component (in a package like a transistor) that has been ruggedised by potting it in an epoxy filled box and addin some leads. If that's the case, then the very same components are used for sensitive electronics without any problems.

Choppers are usually for AC applications, like motor speed controls, light dimmers etc. and they get their name by the process they use to "chop" a part of the sine-curve off and therfore reduce the power going to the appliance.

Jaycar's catalogue lists the output as DC. Of course it may not be pure DC, but I would think i would be near-enough for instruments, especially analogue gauges.

Good luck.

[DavidG]

You want about 6.9 volts anyway. Not 6.0.

[Chipman]

As I understand it, if you tap a 12Vbattery after 3 cells you get 6V. A long time ago they used to make batteries with the lead connections between cells on the top or outside of the battery. Havent seen one for a long time but the connections are still there only under the plastic top. I wonder if you drilled in the right place you could connect to this with a brass screw and there is your centre tap.

Ask a battery shop if this might work. Otherwise, go the two 6V batteries

What about this
http://www.snaptec.com.au/dcdc/pdf/t3.pdf

If the current draw is the same for any two 6V items, they may be wired in series to run off 12 V. BE REALLY REALLY SURE BEFORE YOU TRY THIS!! Ideal for globes mainly

Chipman

[DavidG]

Just re-reading what gauges you have and the age I am suspecting that the gauges may only need 6v for the lights.

Possible exception is the temp gauges, but they may be bulb type.

Check what wiring is behind each gauge.

[Stringy]

Have just checked the wiring;
Water temps are wired.

Speed is by water line into back of gauge-no wires
Oil is oil line into back of gauge-no wires

Amp meter, wired, but - will it matter what Volts this runs on?

Found 1962 on one of the temp gauges, it's starting to look as though this is when it was built, not the late 50's as first thaught!

[DavidG]

Amps is Amps regardless.

The temp guages will need a regulator but should not need much current.

The lights can be changed to 12v

You can buy Cig lighter plug in 12v to Various volt regulators 1Amp from Dick Smiths for $20 - $30. Possibly the easiest way.