OK I know this can be done but I don't want to fry anything, so I am asking for help from others that are more knowledgeable than I.

 

I have a set of KC HID lights that my nephew gave me. They are bright as noon day sun. 

My problem is that they are setup for 24 volts for a HMMWV. 

Can I get 24 volts to these lights out of my 2 batteries already on the truck? What kind of diode (is that what I need?) will I need to get 24 volts without backfeeding 24 volts into the trucks 12 volt system.

 

If I need to I could add another battery to make a 24 volt system separate from the 12 volt system. If I do that how do I wire in the extra battery so I can charge it but again not feed 24 volts back into my 12 volt system?

 

I'm open to some suggestions and any help you can give me here.

 

Charlie

The short answer is NO.  Our trucks have 2 batteries to increase the amperage available but it's still 2 batteries in parallel for 12 volts.  If you rewire to series you get 24 volts (or slightly higher) but is wrong for your alternator, starter, computers, etc.  There are such things as step up transformers but I think it's counter productive & undoubtedly costly.

I wonder if these lights can be converted to 12V? 

The easiest thing would be to get a set of 12V bulbs for it.

 

I am sure it could be done with some diodes and wiring, but ultimately I am not sure it's worth it.

It can be done but as stated the amount of relays and added wiring that will be needed to add just 2 lights will not be worth the effort unless you can find a 12 to 24 converter.

AH64ID they are HID so you can not just change the bulb, HID lights run off of a ballast so the entire light system is different and they are very expensive to replace parts in plus HID has a high initial amp draw to get the ballast to warm up and then they warm up and come to life the amp draw drops off.

I missed the HID part.... I hadn't had enough coffee I guess.

I know like our old Military Fire Trucks are 24V system and we break out of the the batteries with 12V for all the electronics.

 

But trying to go from 12V to 24V is tougher yet because of the requirements of the truck. Even if you did there is no way for the alternator to keep up with 24V system (12V alternator). So the easiest plan is getting a 12V to 24V converter box like Wild and Free suggest.

It can be done, but like W&F said, the amount of wiring and relays make it real tough to to. I recall some semi trucks had a 12/24 system in them. 24v was for the starter and 12v to run everything else. All batteries were 12v and charged by the alternator.

edit: I got to thinking about this..... Why not just put a transformer in to increase the voltage? Something like this: http://www.ebay.com/itm/24VCT-24V-12V-Transformer-12V-0-12V-CT-1A-110Vac-220Vac-to-24Vac-12Vac-free-shi-/270826572472

Transformers only work with AC power. DC has to be converted to AC the stepped up then converted back to DC by diodes.

Well, shoot. I forgot about the need for AC and transformers.........