12v and 24v question...

[jeepdreamer]

So being an electrical nimrod...can someone explain somthing to me please?
If one had a diesel truck like my 99 Dodge with its 2 12v batteries...Would it be even possible to wire in a couple 24v offroad lights from the existing system? Kinda a dumb/odd question but I have a pair of military off road lights I found at the dump and wondered if they could be made to work...? Anyone?
edit- Before someone asks and since I forgot, these don't have replaceable bulbs as they look a LOT like LEDs...ahem.

 

[Deltarat]

So being an electrical nimrod...can someone explain somthing to me please?
If one had a diesel truck like my 99 Dodge with its 2 12v batteries...Would it be even possible to wire in a couple 24v offroad lights from the existing system? Kinda a dumb/odd question but I have a pair of military off road lights I found at the dump and wondered if they could be made to work...? Anyone?
edit- Before someone asks and since I forgot, these don't have replaceable bulbs as they look a LOT like LEDs...ahem.

Your two batteries are in parallel, so only 12 volts total. No way to run the 24 volt lights on the existing system.

 

[ratkin]

Maybe you could figure out how the set-up works in the Chevy CUCV's for the military. They have 24v and 12v in the same truck.

 

[Hill Bill E.]

Maybe you could figure out how the set-up works in the Chevy CUCV's for the military. They have 24v and 12v in the same truck.

When it's a 24V system, it's easy to run 12V items. I ran a CB and a car stereo in my 5 ton while in the service. (connected to just two of the four 6V batts)

But it doesn't work the other way around, as far as I know.

 

[hillbillyjake]

if you were to run a wire (fused) from the + side of one battery to teh - of the other and then to the hot of one light to the hot of the other. then run a ground wire from a good ground (frame or body) threw your switch and then to each light.

would this not work? if i am thinking correctly the lighting system would be a seperate system from the rest of the truck. and if you where to run the ground threw the switch there woudl be no extra hot wires entering the cab.

once again, please correct me if i'm wrong. just a thought

 

[ratkin]

Maybe this link will give you some modification options

From Conversion of M1008 and M1009 Electric Systems to 12 Volt:

The Commercial Utility Cargo Vehicles (CUCV) are commercial vehicles modified to meet the needs of the U.S. Military. These vehicles come in five basic configurations: Cargo, utility, ambulance, shelter carrier, and chassis versions.

In the late 80's General Motors (GM) produced them. The GM versions are the latest of the five CUCV variants. The GM models are named, the M1008 (Cargo), M1009 (Utility), M1010 (Ambulance), M1028 (Shelter Carrier), and M1031 (Chassis). This report will concern itself with the electrical systems of the M1008, which is a diesel GM pickup truck, and the M1009, known in its civilian life as the Chevrolet Blazer/GMC Jimmy.

The M1008/M1009 were originally designed for civilian use, their heritage includes a 12-volt electric system. The military, of course, uses 24-volt electric appliances. Because of this, General Motors made some changes to the electrical systems of these military models. There are two alternators and two batteries, each of which is 12-volt. The alternators and batteries are connected in series to create 24-volts. The driver's side alternator charges the vehicle's front battery. This battery and alternator supply power for all the 12-volt components/systems. Both alternators charge the rear battery.

The electrical system of the M1008/M1009 is a civilian 12-volt system modified to allow 24-volt starting and supply 24-volts for military accessories. The only true 24-volt component is the starter motor. The glow plugs and glow plug relay are 12-volt components. Their 24-volt power supply is reduced to 12-volt by the use of a resistor bank. All running lights, interior lights, and gauges are 12-volt components.

As you can see, General Motors modified what was designed as a 12-volt system into a quasi-24 volt system for the military. Converting it back to a 12-volt system is neither costly nor difficult. The M1008/M1009 electrical system can be utilized in one of three ways.​

Hope this helps!

 

[dieselcruiserhead]

It is possible to go both ways, 12V or 24V if you have two batteries. But is a little difficult and would take some relays. I wouldn't recommend it, not for a set of off road lights unless they are really really cool. That said, the whole world should be on 24V. Japan tried it for a little while, trying to right the wrong of 12v.

 

[eugene]

if you were to run a wire (fused) from the + side of one battery to teh - of the other and then to the hot of one light to the hot of the other. then run a ground wire from a good ground (frame or body) threw your switch and then to each light.

would this not work? if i am thinking correctly the lighting system would be a seperate system from the rest of the truck. and if you where to run the ground threw the switch there woudl be no extra hot wires entering the cab.

once again, please correct me if i'm wrong. just a thought

Problem you run into is then when starting the 12v batteries are paralleled so your 24v circuit shorts out.
I suppose you could get real fancy with some relays to make a 24v system then the relays disconnect that wiring and connect them in parallel for starting then back to 24v for running.
Or just see if you can find a small 12v to 24v convertor power supply.

 

[ratkin]

DC DC Converter

Or just see if you can find a small 12v to 24v convertor power supply.

CONV DC-DC 12V IN 24V OUT @2A - 9919371224
Description: Order 'conv dc-dc 12v in 24v out @2a - 9919371224' online from Digi-Key. Manufactured by Weidmuller. Digi-Key part number 281-2013-ND.
Weidmuller Dc Dc Converter Power Supply 50W Input: 9 ~ 16V Output: 9919371224
Category: Power Supplies >> DC DC Converters , 12v to 24v Converter

 

[eugene]

TI's powertrends are cheaper but you have to add a couple caps and put it in your own box, you could make a couple A one for $50. I had an old system running off one a few years ago. Just doesn't seem worth it for some lights.

 

[hillbillyjake]

after i thought about it for a little bit it seemed that the one system woudl back feed the other at some point. i think it could be done with relays though.