Rods 'n' Sods - UK Hot Rod & Street Rod Forums banner
1 - 9 of 9 Posts

·
MR UN-POPULAR
Joined
·
2,680 Posts
Discussion Starter · #3 ·
is that what you have to do!! thats why im asking as ive no idea when it comes to electric's .... i want to run all the standerd pop dash plus the fuel sender in the tank but using a 12 volt battrey, what do i need to do or am i better ditching it all and getting new stuff!
 

·
Premium Member
Joined
·
2,455 Posts
Hi

Yes, you need tp place a dropper in the circuit line.
This VW place sells them http://www.coolairvw.co.uk/ca/mia/d/6v+12v+voltage+dropper+static/pid/6554318
or try ebay. I think Demon tweeks supply them too, and 'Mart' on the NSRA. Pop Browns and NAMCO sell them too.

The smaller items such as fuel sender and water gauge (If electric) only require small droppers. The heater circuits though draw high loads, so a large dropper is required. This causes lots of heat, so a good heat sink is also required.

Dont forget you need a 12v coil, as well as light bulbs inside and out.
The 6v starter is ok, it just spins faster which most people find is a bonus!

I have stayed on 6v with my car. You can get a 6v alternator, 6v halogen lights, 6v electronic ignitionand coil, and for those important items you can buy a 6v to 12v Voltage Booster to power up a cd/radio or cigarette lighter to power your sat nav/ mobile phone. I think this is a better option personally.

I have 'borrowed' the following from a post on the other channel
For small stuff, you can use a resistor in the circuit. A heater motor would be OK for this method if it's not really powerful.

Unlike using an electronic voltage dropping device, which will power a number of devices; you'll need to fit a voltage dropping resistor to each circuit individually.

To work out what resister you need, you have to know the current the device uses and the voltage you want to drop. So, for 6v device using 1 amp, you need to drop 6v on a 12v system.

Voltage to drop
______________ = Resistance you need in series with your device
I (current)

6 volts to drop
_____________ = 6 ohm resistor needed
1 amp for the device

You need to work out the power rating for the resistor: DC Watts = Volts x Current

So in this example you'd need a 6W resistor - The power is calculated from the 6v that you have across the resistor x the 1 amp current in the circuit

Using resistors works well for small devices that use a constant current, but if you're dropping the voltage for a 10A device, you need a resistor rated at 60W power, that's quite a bit of heat to get rid of and the resistor will need a heat sink fitted.

Also if the current isn't constant, e.g. a fuel guage circuit, you'll only get a correct reading at empty or full on the guage according to whether you drop the voltage against the "empty" or "full" current.

RS components are a good supplier for power resistors and heat sinks.
 

·
MR UN-POPULAR
Joined
·
2,680 Posts
Discussion Starter · #5 ·
thanks for the help mate :tup: wont be a heater in the car and the engine isnt the standerd item..... ill be getting a new loom made but was'nt sure if the 6v guages would be ok.
 

·
Semi Proffessional Prat
Joined
·
3,489 Posts
That thing on VW site would be noo more than about a quid, if you bought it direct from electronics place.

As mentioned, your gauges need 6 volts, a dropper is relatively straightforward. If Mart can't make you one, gimme a shout and I will knock you some up. I take it you are going negative earth?

Andy
 

·
Registered
Joined
·
267 Posts
Pop gauges work fine on 12V. Swap the bulbs to 12V ones and the fuel gauge will read full until there's about 1/4 left, when it drops quite quickly. Put a resistor inline with the fuel gauge and it's a lot more progressive.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top