From: Jim (W7LS@BLARG.net)
Date: Thu Nov 11 2004 - 10:19:00 PST
Hi, Everett.
That technique works just fine for something like a siren, a heater, or a motor. However, for radios and other electronic equipment, it could blow the radio because the 'voltage reducers' act by sharing the load, and when the radio is not drawing much load, the voltage across it will rise above safe levels.
A 'voltage converter' is an electronic box that contains some whiz-bang (technical term) parts that charge up a coil and then discharge it at different rates and so on, such that it creates a smooth, constant 12v output, irregardless of the load you put on it. It does this at a very fast rate, like a few thousand times a second. Sometimes you can hear the whine, not unlike an alternator whine on the car radio.
The 'voltage reducer' is maybe $20 and the 'voltage converter' is more like a hundred bucks, depending on what ratings you need. Hope this helps. Jim
On Thu, Nov 11, 2004 at 6:30am everette <194cbteng@bellsouth.net> wrote:
> I do not know that this would help; however this is what I did
>
> I was a volunteer fireman several years ago and the only siren I had was 6
> volt, and my truck was 12 volt, I purchased some "voltage reducers" which
> were a ceramic device with a coil made into them, you put 12 in one side and
> got less on the other, I had to use 3 of them in series before the output
> voltage on last was 6 volts, I do not know all there is to know about this,
> only that I used it for several years without any difficulties with siren or
> with truck electrical system
>
> Everette
>
> .
> ----- Original Message -----
> From: "brian fowler" <bjlf@hotmail.com>
> To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
> Sent: Wednesday, November 10, 2004 11:05 PM
> Subject: [MV] 24volt to 12 volt converter
>
>
> A few days ago someone posted a link to a site that had a 24 volt to 12 volt
> converter with a sustained load of 25 amps. I have lost the link could you
> repost?
>
> I am with a volunteer fire department that has been given a 5ton m927 we are
> making into a tanker, That is coming along very well.
>
> We have seen the options on roscommons site for 12 volt changes. We were
> originally going to go right off the last battery to run a 2way radio and
> some warning lights. But if the converter is reliable we would use one.
>
> What suggestions do you have?
>
> Thanks
>
> Brian Fowler
> New London VFD
> New London Missouri.
>
>
>
>
>
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