Where to find accessory power on a deuce...

Hi,

I built a little 24V to 12V regulator to handle cell phones, and gps load, but I am wondering where I could easily find 24V to power it.

Is there a terminal board somewhere in the cabin that is easily accessible?

Thanks!

-Chuck

On my deuce (fire truck) there is a series of breakers that are in front of the gear shift lever on the fire wall (cabin side) there are at least 2 unused that are full time 24v (THAT i CAN RECALL) Either one will work, specially if you feed it through the 20A breaker. That is where I am getting most of my power for my radios and strobes for my truck. Cannot get any easier than that! Good luck

Hi Scootertrs,

Thanks for the info! Do the terminals take bare wires, or do they want to see spade lugs?... Or something else?

-Chuck

These are threaded lugs. I put closed end wire connectors with holes just big enough to slip over the stud. I try to use at least 12 ga. wire. you can also attach several power outs from the "breaker" side of the breaker as long as they do not exceed the breaker capacity. working with 24 volts is very forgiving when you have to deal with amperage... a 20 amp circuit goes a long way. Good luck

Thanks for the info! Now I know what to look for. I was quite concerned that I wasn't going to be able to keep my gps and cell phone charged up.

The little adapter I made fits in a small ammo box, and has two cigarette lighter sockets mounted in it. The adapter drops 24V down to 13.7V, and float charges a 12V 7.5AH sealed lead acid battery. That way the cell phones and gps can be used regardless of the state of the deuce's electrical system.

-Chuck

Just went and gave mine a quick look and saw no breakers. Are they under the dash behind something?? It would be nice to have.

I got concerned when I saw Ride2Kill's statement that his deuce has no breakers under the dash. I took a look at the -34 for the deuce, and the wiring harness has no accessory taps anywhere that aren't already in use.

So, I guess the question is answered for red fire truck deuces, but is still open for plain old M35A2 deuces.

Where do I get accessory power to run my 24V to 12V converter?

-Chuck

Ok, I see that. It appears to have waterproof connectors on it.

Where would one go to power a more significant load, such as a tactical radio? Is there a common lug somewhere where all of those sorts of circuits are intended to be connected?

-Chuck

You can connect to the terminals on the slave recepticle, located next to the passenger seat.

That would probably be the most convenient location. I had best make sure I fuse the wire, though.

Thanks!

-Chuck

you could install a few accessory buss bars. Tie in at main ground and at same point slave cable is connected to the battery.

AN/ARC186 said:

you could install a few accessory buss bars. Tie in at main ground and at same point slave cable is connected to the battery.

Click to expand...

Very clean install, sweet.

stumps said:

Ok, I see that. It appears to have waterproof connectors on it.

Where would one go to power a more significant load, such as a tactical radio? Is there a common lug somewhere where all of those sorts of circuits are intended to be connected?

-Chuck

Click to expand...

Use the MX7777 suppressor for all your supplies, it's wired to the battery and provides the protection you need for all your accessories. Problem may be finding the cables, but they are out there.
Image below shows location of the unit (disregard the mess around it).

Generally, you don't want to put accessory loads right on your battery. Doing so causes the voltage regulator to raise the voltage on the real accessory point.... wherever that is. My puny little adapter wouldn't matter, but I am thinking for the long term.

Where do the tactical radio loads get connected?

I'd work out these problems for myself, but I don't have my deuce yet, and I am trying to prepare for its recovery. To that end, I need a simple, safe place to hook up, that doesn't require butchering anything up.... Preferably something within the passenger compartment.

-Chuck

I always thought that you place the fused load as close to the battery as possible if not right on it. The battery actually then acts as a voltage regulator/dampner of spikes of sorts from the rest of the truck. That way if the accessory causes a voltage drop, the alternator/regulator can compensate and keep the battery up to snuff. If I am doing it wrong... please don't be bashful and let me know... I have a bizillion watts going to my strobes, girenes and radios in my fire truck... (sorry... can't help it... always been a sucker for strobes and girenes...) would really get depressed if I had a smoke test ... specially in this economy... On my truck I have 24 Acc. power coming from the battery-direct- through a breaker-to a relay that is wired to activate from the accessory post... Good luck

stumps said:

.....
Where do the tactical radio loads get connected?
.....Chuck

Click to expand...

Via the MX7777, perhaps I wasn't clear on that point in the post above.

The battery's primary purpose is to start the vehicle. Its secondary purpose is to take up the accessory load, at idle (or off), if the generator can't handle it. The generator is supposed to supply the accessory power exclusively.

To make all of the regulation work, the generator senses the voltage at the accessory point, and adjusts itself to keep that voltage at a nominal value that will keep the battery charged. A single wire, with no other loads, is supposed to go from the accessory point, to the battery to charge the battery.

The battery takes relatively little current to keep its charge topped off. It will take a fair burst of current if the battery is down from starting, or running a load with the engine off. But once the battery is up to charge, it settles down to a float charge current.

If you take your accessory load off of the battery, you will be dropping more voltage in the charging wire, and that could cause the battery to discharge somewhat.

The accessory point can be anywhere, including at the battery terminals. I haven't studied the deuce's electrical system yet, so I don't know how they are doing things, but I would expect it to be pretty much like any farm tractor

The accessory point is wherever the alternator regulator senses battery voltage.
I hear that many deuces have a one terminal alternator. If that is true, the accessory point on those deuces is wherever that big alternator wire goes.

-Chuck

I usually just use a portable cig recepticle with clips and hook it to one battery, then run the cable for the GPS/phone out the pass door and plug it in. I just found a slave cable plug that has two cig recepticle made for the military. Haven't pluged anything into it to test yet. If it works and drops the voltage, I will just plug that into the slave recepticle and run the plugs out the window for now.

the breaker on the firewall in front of the driver (engine side) is the main circuit breaker. You can tap off of that for power, either on the batt side if you are going to add another fuse or breaker, or after if your load isn't that big. I tapped it and added another breaker when I had my convoy lights on the m35.

What Bjorn is trying to say, is a radio or VIC-1 (intercom) system is powered through a surge/polarity protector, the XM 7777. There is a cable that connects to the batteries, and then to the XM7777. The XM7777 has two outlets. If you can find the cables, you can tap off one outlet to run and power your voltage converter, then it will also be protected. And you would still have a power connection available to connect a radio/intercom in the future.

There isn't an easy way to connect things right under the dash unless you get a Y spliter for the waterproof connections or splice into the wires the hard way.

cranetruck said:

Via the MX7777, perhaps I wasn't clear on that point in the post above.

Click to expand...

I understood that, but I am pretty sure my deuce doesn't have an MX7777 installed... unless they were a standard item, and then I would have to wonder why they aren't shown in the -34 manual.

So, maybe the correct question is where does the MX7777 get its power?

You said it was wired to the battery, but is that directly to the battery terminals, or some other point?

-Chuck