Cheap and easy 24 to 12V?

[Lax]

I know this subject has been talked about a great deal but has there been any really good ideas to get a 12V from 24V that does not cost hundreds of dollars? I am particularly interested in 12 volt for high powered driving/spot lights, an emergency light bar, CB radio, mobile phone charger, etc. Not necessarily all of those at one time but maybe. Any ideas out there that have been tried and done with success? Thanks.

 

[m16ty]

Not that I know of. The cheapest is going to be a 12/24 volt converter but there's no way it will handle the loads you have in mind. If you could find some 24 volt spotlights a converter would run your radio, phone charger and such.

You could convert everything to 12 volt. You would have to change all your gauges, bulbs, and maybe your starter.

About the only other option would to add another separate 12 volt system ( 12 volt alt. and another battery completly separate from your 24 volt system). I know of some that have done it this way but I think it really complicates your electrical system and cost a lot to install and keep up. I'm of the opinion to keep everything 24 volt ( maybe a converter to run light 12 volt loads) or change everything to 12 volts.

 

[rosco]

Where do you get the converters? Sounds like your describing something that has a "fixed load"? Thanks

Lee in Alaska

 

[mangus580]

LAX... come check out my 12/24v alternator sometime... I think thats the ideal way... or maybe an add-on alternator.

 

[m16ty]

Where do you get the converters? Sounds like your describing something that has a "fixed load"? Thanks

Lee in Alaska

I don't have one in my deuce but my m715 had one in it when I got it. You just hook 24V in and out comes 12V. Since my m715 had one in it when I got it I'm not sure where to get one. I've heard of people buying them off e-bay.
To further answer you're question, It's not just a resistor where when the load goes up the voltage will drop. I don't know what's in there but it looks kind of like a radio amp and supplies a constant 12 volts to whatever you hook onto it as long as you don't exceed the max amp draw.

 

[bottleworks]

A battery equalizer can handle the loads you need...But you will need $300-800 for one. With it, you can pull current off of the lower battery. The equalizer will then keep both batteries charged evenly with the 24V alternator. A Vanner 60 Amp unit is on eBay for $300. Most transit buses use them because half the bus runs on 24VDC and the other on 12VDC.

Just another thing I wish I could afford...

 

[bottleworks]

P.S. Opcom Installed a battery equalizer in his Deuce. And added a relay to kill it with the accessory switch off.

http://www.bunkerofdoom.com/mil/m35/vic4/index.html

 

[cranetruck]

I like, what I call a Point of Load (POL) regulator. It is a regulator, which is designed for particular load ranges and used where needed.
I have one for the CB, which can handle 3 amps max. If one was needed for another load, spot light or whatever, a different regulator would be used for that application alone. Redundancy adds reliability and there is no need for one high capacity regulator, which may be very costly.

My CB regulator is home made, so it only cost me left over parts...got a picture somewhere....

I did see Patrick's "balancer" thread and left him a question, that wasn't answered, it had to do with balancing the batteries after the truck was shut down.

 

[OD_Coyote]

I was thinking about buying one of these....

http://www.powerstream.com/dc1-isolated.htm

 

[Big Mike's Motor Pool]

for the lights you can run 12v lights on 24v system if you wire them in series. i have spotlights hooked up on the back of my truck in series for reverse lights wired like that. they work nicely

 

[bottleworks]

I did see Patrick's "balancer" thread and left him a question, that wasn't answered, it had to do with balancing the batteries after the truck was shut down.

I guess the key is to design the system for your needs. If you install an equalizer that handles only 20 amps and you have been averaging a load of 50 amps, you didn't setup the system to meet your needs. In the transit buses, the battery equalizer is always powered (Not with Opcom's setup). Even if you turn off the battery disconnect, the equalizer will still have power. Even if the engine was turned off with the batteries not at the same voltage, the equalizer will equalize them. This also allows you to run 12V accessories with the engine off, but keep the batteries even.

 

[Crazyguyla]

There are 12v/24v military alternators. I seen them on newer Humvee's with electronic transmission controls. The alternators are not cheap tho. I don't have a price figure for these alternators.

 

[therbert]

Does the alt have the 3 screws the allow connections to the AC side of the rectifier? I know on newer leece-neville alts come with these connections. I use to work for someone that made high freq transformers just for this purpose. It would be the cheapest way to go. Everything is analog and the internal requlator keeps the voltage already. So it just need to be rectified at 12V.

 

[m16ty]

A battery equalizer can handle the loads you need...But you will need $300-800 for one. With it, you can pull current off of the lower battery. The equalizer will then keep both batteries charged evenly with the 24V alternator. A Vanner 60 Amp unit is on eBay for $300. Most transit buses use them because half the bus runs on 24VDC and the other on 12VDC.

Just another thing I wish I could afford...

There's a local guy that just bought a bunch of transit busses for scrap. If anyone is interested I'll stop by and see if I can find some equalizers for a good price. Do you know where they would be on the bus or what they look like?

 

[m-35tom]

they are probably near the batteries and most likely made by vanner. i would love to have one........

 

[m16ty]

they are probably near the batteries and most likely made by vanner. i would love to have one........

I'll see what I can find out. Was there last week and they were taking the engines out to resell and were going to scrap the rest.

 

[goldneagle]

I would be interested in one for the right price too.

 

[bottleworks]

If anyone is interested I'll stop by and see if I can find some equalizers for a good price.

PM Sent!