12-volt vs. 6-volt Police/Fire Equipment

Jim McDaniel

Jim McDaniel

Junior Member
I have a 1951 Ford Tudor police car, essentially all original or stock. Six-volt system. I have a perfect siren I'd like to add to the car but it's 12-volt. Most 6-volt equipment is too large for the space I'm trying to put it. Can an inverter of some sort be used to "step-down" the 12-volt to 6-volt? I'm told re-wiring is not really an option. If so, anyone have a product and source? This car was originally a public use vehicle in North Carolina, and I've restored it as a Lee County Florida Sheriff's cruiser. Original 1950s decals and Model 17 Beacon Ray (bubble). The red spotlight is the original light that was on the car in '51. Main non-stock items are seat belts and headers with dual glaspacks. Sorry, but I love the sound!
 
Check on e-bay , they have a 6 volt pos ground to 12 volt neg ground inverter for about $59.00, they are supposed to work fine .
 
Just be real careful where you put it. I had one for a 12 volt radio and and the inverter would get very hot. Almost burn your fingers.
 
Make sure the inverter will handle the starting current of the siren.
The instantaneous starting current is considerably higher than the running current.
Solid state converters don't like big spikes.
 
I was thinking the same, that siren will take a big pull on the system. As it's only used occasionally for a bit of fun, could you just carry a 12V battery just for the siren? It's not like you wouldn't get home if it went flat.

Mart.
 
"Can an inverter of some sort be used to "step-down" the 12-volt to 6-volt?"

Umm, the converter steps up 6v from the battery to 12v with a transformer and goes DC to AC and back to DC.
 
Hi just a note: If you want some more fun, check out the suspension specs for a '53 Police car. They used all station wagon chassis parts, springs, wheels, swaybar 3/4 "or 7/8, also heavy seat springs and a bigger generator. I used the suspension spec's in a '53 coupe and it made a real difference. Newc
 
Thanks to all for your input and thoughts. I'll try e-bay to see if they have anything that will work. I do only use it occasionally, but the separate 12v battery idea sounds a bit awkward to install and use. At least it sounds like the inverter idea will work. I'll check around to see an I can find on. Thanks again to all.
 
The old siren I had used the windings similar to a starter motor, many amps, at least 50, buy one of those cheap jumper boxes, keep it with your modern car except when you want it for the siren---then clip it to siren connections, a voltage converter for the siren amps will be $$
 
Kurt has a good idea but instead of clipping it you could wire a male connector that plugs into a powerpoint on it. Similar to a cigarette lighter. I personally would stay away from an inverter I needed to start up an electric motor due to the high start up current.
 
If you have a tar top battery if you can tap into the middle of battery you will have all the power you need and 6 volts.I did this to my 51 ford, went to 312 v8 12 volts and needed the radio.Had to liston Fuff the Dargon.
 
mrtexas said:
"Can an inverter of some sort be used to "step-down" the 12-volt to 6-volt?"

Umm, the converter steps up 6v from the battery to 12v with a transformer and goes DC to AC and back to DC.
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Rats! I indeed stated that backwards. I need to step up my 6-v positive ground to 12'v to run the siren. Thanks for the catch. ~Jim
 
Kurt in NJ said:
The old siren I had used the windings similar to a starter motor, many amps, at least 50, buy one of those cheap jumper boxes, keep it with your modern car except when you want it for the siren---then clip it to siren connections, a voltage converter for the siren amps will be $$
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Good suggestion. I have two of those jumper boxes. I might just try that. Will try to not "Better" be the enemy of "Good Enough." Sound like this might just work.
 
Well thats a different story.
I would get a marine battery 12 volt and play with the siren tell it goes dead.How many cars you going to pull over. LOL
 
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