Rods 'n' Sods - UK Hot Rod & Street Rod Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
Hi all, Busy re-wiring my 49 chevy truck, using a rebel wiring kit, but i'm going to need to reduce the voltage to the heater blower ( recon about 4 amps) and the gauges/feul guage. I can source the necessary parts in the states, but have drawn a blank over here so far, Anyone out ther know of any supplier over here please ?? Regards,,Gaz
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #5 ·
Thanks Darren, was makin sure that whatever there was that would reduce the voltage, would handle the amperage, . thanks for link, hopeng for a uk supplier, but looks like am gonna have to be patient !
 

·
I'm Not Jed Clampett
Joined
·
2,725 Posts
to provide 6V @ 4 amps from a 12V supply you'll need a 1.5 ohm resistor like this: 5% 50W 1.5 Ohm Chassis Mount Wirewound Aluminium Housed Resistor | eBay it needs to be bolted to a metal surface to act as a heat sink, mine is fitted to the top of the heater box - but mine is there with some other electrickery to provide a two speed fan.

Arithmetic is voltage to drop divided by desired current in circuit = series resistor value. So 6V ÷ 4A = 1.5Ω

Voltage dropping resistors only work in a circuit where the current is constant, so not really any good for fuel gauges etc. Digital converters like the one Darren has linked are ideal for low current stuff.
 

·
Semi Proffessional Prat
Joined
·
3,489 Posts
A resistor ( or dropper) as described will only work if the resistance of the dropper is the same as the resistance of the motor it is feeding.
A better way would be a solid state dropper, that gets fed with 12 volts, and give 6 volts out. Much the same way as a 24 volt to 12 volt dropper for lorries to run 12 volt accessories.

Fuel gauge dropper is relatively easy also, providing you are on negative earth, and can use a soldering iron.
 

·
Registered
Joined
·
1,416 Posts
If you use one of the classic batteries with external bars across the top you can tap off 6 volts at the mid point. The 6 volt tap is either + or - depending on which end of the battery you put the other connector. I got mine professionally tapped by Lincon at no extra as far as I recall. The 6 volt line has its own fused circuit and powers the fuel gauge and semaphore solenoids and I would think it could deal with much more than you need. Dave
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #11 ·
Thanks guys, much appreciated, wouldhave had to obtain from the states, but the mort n postage gats silly, thatl do te job tanks for the links ! Gaz
 

·
Premium Member
Joined
·
1,662 Posts
If you use one of the classic batteries with external bars across the top you can tap off 6 volts at the mid point. The 6 volt tap is either + or - depending on which end of the battery you put the other connector. I got mine professionally tapped by Lincon at no extra as far as I recall. The 6 volt line has its own fused circuit and powers the fuel gauge and semaphore solenoids and I would think it could deal with much more than you need. Dave
That or run two six volt batteries in series , then just pull the six volt supply off one of them and the car still gets the 12 volts off the pair. Nothing else needed.

Bob
 

·
Semi Proffessional Prat
Joined
·
3,489 Posts
Can't you change the motor for a 12 volt one?
 

·
Rekindled Dream
Joined
·
2,064 Posts
If you use one of the classic batteries with external bars across the top you can tap off 6 volts at the mid point. The 6 volt tap is either + or - depending on which end of the battery you put the other connector. I got mine professionally tapped by Lincon at no extra as far as I recall. The 6 volt line has its own fused circuit and powers the fuel gauge and semaphore solenoids and I would think it could deal with much more than you need. Dave
:yeahthat: beat me to it. :shake:
 

·
Registered
Joined
·
140 Posts
Geordie Paul keeps 12v - 6v droppers in stock, ones for motors and also the ones for gauges.
 
1 - 16 of 16 Posts
Top