12v equipment

[comdiver]

I have a 24v-12v coverter. It is rated for 10 amps. Could that be hooked up to a 12v battery like a charger giving me a 12v system that would allow me to run larger loads than 10amps for short periods of time? Would it over charge the battery or taper down like a battery charger?

 

[6x6guy]

The general consensus is that prolonged and consistent drain on one battery will eventual
destroy one or both batteries, if your using it for a few amps for a phone charger, and other
low draw devices you should be alright, how ever if your going lets say over a few amps and a consistent drain would would want to install a power converter from Memphis Equipment
designed for 24 volt systems to 12 volts and will handle up to 25 amps and runs off of booth batteries and will not cause a unbalance in the charging system and destroy the batteries.
Now lets assume you want even more amperage -lets take one of my M35a2 for example
I have a 5000 LB crane mounted and lights with a 12 volt system in the rear of one of my trucks, along with a 12 volt heater blower defroster unit and lots of other 12 volt goodies with a amperage draw is well over 100 amps- not that the electrical amperage drain is on all the time for that scenario, you'll need another 12 volt power source- my selection
was a Delco Remy single wire -160 amp alternator- mounted above the 24 volt unit making my own mounting brackets and installing longer V belts. You will have to add a additional battery or two for storage capacity and in my case also installed a 12 volt fuse box and some 12 volt relays for the bigger draw devices.

 

[Carl_in_NH]

The simple answer is, Yes, using the 24V-12V converter as a source to charge a 12V battery used as a 'buffer' to run some 12V gear for short amounts of time is perfectly fine.

Remember, you'll want to get a nice full charge on that 12V buffer battery when you're done using it - and that may not happen if you only power the converter to charge it while running the truck. If you leave the converter running all the time, you'll discharge your 24V system - so that's not an option. It would be up to you to put a charger on the 12V battery to insure you've got it fully charged now and then. It all depends on your usage of the 12V system - if you use light loads and not very often, it will be charged just fine by the 10A converter.

Think of it this way; the 24V battery system takes care of itself, you need to exercise some manual care for the 12V system.

To insure you don't damage the 12V battery, make certain your no load output voltage on the converter is no greater than 13.8V, and you'll be just fine.

 

[cbvet]

I believe Carl has it exactly right.

 

[comdiver]

Do you think with a light load or limited use and long trip would it overcharge? Deep Cycle or regular starting battery?

 

[Carl_in_NH]

As long as you have your 24V-to-12V converter set so that it never puts out more than 13.8V when disconnected from all loads (and the 12V battery), it will never overcharge your 12V battery.

It would be emulating a 10A alternator / charging system if configured this way.

Most DC-DC converters have an adjustment to set the output voltage, and that's what you want to tweak to 13.8V unloaded.

 

[tennmogger]

I concur. That's the setup I use in my 24v vehicle. A Wilmore 24 to 12 converter float charges a 110 AH deep discharge storage battery. I have not had to do any maintenance on the 12v battery. The average charge from the converter more than offsets the drains from my radios. Most batteries of this type can be float charged indefinitely, but a good equalizing charge every few months is a good idea.

The type 24-12 converter is important. It must have over current protection (not just a fuse) and must tolerate a battery connected to it's output. Some converters will act as a load if turned off (no 24v input). Cheap converters will discharge the 12v battery back into the converter. A diode in series will fix that but the converter output must then be turned up enough to compensate for the diode drop (0.6 v approx). Or you can put a relay on the output of the converter also, to disconnect it when the truck is off.

The converter I use has a 24v 'logic' terminal to turn it on and off from the key, and allows batteries to be connected without reverse flow, so I don't need any relays. It only drains a few mA when it's off.

FYI check out Wilmore at Wilmore Electronics-Home Page: dc-dc converters, dc-ac inverters and power supplies

I also use some Newmar converters, and I think someone on the SS sells Newmar converters at a good price.

Bob

As long as you have your 24V-to-12V converter set so that it never puts out more than 13.8V when disconnected from all loads (and the 12V battery), it will never overcharge your 12V battery.

It would be emulating a 10A alternator / charging system if configured this way.

Most DC-DC converters have an adjustment to set the output voltage, and that's what you want to tweak to 13.8V unloaded.