Wiring Question on M1165

[jim1131]

I have a question about keyed accessories that are 12v.

Since the starter is 24v you can’t run 12v through the off-run-start ignition correct?

So, would a smart way to run 12v stuff, that turns off with the truck, be to run a power supply straight off the dual voltage regulator? Then there would only be power when the truck is on, and it wouldn’t be causing an imbalance with the batteries.

The panel behind my batteries is always on.

The voltage regulator will keep the rear battery equalized. Since you are equalizing the rear battery through the voltage regulator wouldn't it always have power?

 

[Coug]

You would need to run it through a constant duty solenoid/relay rated for the load, that is connected to a switched power source.

The Orion 70 amp 24-12 converter has a built in relay to do exactly this (and if you're pulling more than about 30 amps of 12V you should really use a converter anyway)

 

[thoner7]

The dual voltage regulator 14V tap is connected directly to the batteries, it is hot all the time so you will need to use a relay with a 24V coil, coil goes to a switched supply (ING terminal on the regulator is one place) and ground and the contacts going between the 14V tap on the batteries (or the 14V tap on the reg, more possibility of getting noise in communications equipment) and your switched 14V load.
REMEMBER to fuse both the switched 24V tap for the relay coil and the 14V tapping point to the relay.
And of course ANY relay added needs to have a diode across the coil to reduce reverse EMF.

Thank you, what you say makes sense about the 14v lead on the alternator.

The rest of what you said is way over my head unfortunately. I don’t know what a relay, coil, diode or EMP means. Is there a diagram out there that would make sense of it?

 

[Mogman]

Thank you, what you say makes sense about the 14v lead on the alternator.

The rest of what you said is way over my head unfortunately. I don’t know what a relay, coil, diode or EMP means. Is there a diagram out there that would make sense of it?

Electromotive force (EMF) is voltage, when you energize a coil (as in a relay) it creates a magnetic field, when you remove the power the magnetic field collapses across the coil and induces a reverse polarity voltage, this can be depending on the impedance (resistance) of the circuit thousands of volts. (basically how an ignition coil works)
if you are controlling the power with a switch (IE the run switch) it causes pitting of the contacts, if you are using a semiconductor (transistor) switch it will burn out the switch.
EDIT, the diode across the coil is installed where it does not conduct when the coil is in the "on" state then it does conduct the reverse voltage when the coil is de-energized, generally keeping it under 1V, some quality relays have these diodes built in.
As far as slaving a relay off of the 24V switched power to control the 12V accessories, if you do not understand that then I would suggest finding someone familiar with automotive wiring and circuits to help you out.

 

[Autonomy_Lost]

This will explain everything

 

[jim1131]

You would need to run it through a constant duty solenoid/relay rated for the load, that is connected to a switched power source.

The Orion 70 amp 24-12 converter has a built in relay to do exactly this (and if you're pulling more than about 30 amps of 12V you should really use a converter anyway)

your 400 amp generator gives 50 amps on the 14v side

 

[Coug]

your 400 amp generator gives 50 amps on the 14v side

50 amps max. The TCM is going to use some of that 12V feed.
The reason I say 30 max is because you really don't want to max out the amount of power draw on the circuit if you can avoid it, so 30 amps plus whatever the TCM is drawing keeps you below 40 amps.

 

[thoner7]

REMEMBER to fuse both the switched 24V tap for the relay coil and the 14V tapping point to the relay.
And of course ANY relay added needs to have a diode across the coil to reduce reverse EMF.

I’ll stop at O’reilys or autozone and hopefully one of the people there can help me get the right parts and maybe even walk me through the wiring.

But if I understand right, I will take power off the ignition switch (which is 24v) , put an inline fuse in, then connect to a 24v relay (which will act as a switch that simply turns my 12v stuff from off to on). So separately I will have a fused 12v line going into the relay, and then a load going out to my accessories.

FWIW I have the 200amp alternator. Idk what amps that puts out on the 12v side.

It seems that most of these relays are 30 amps? So I’d use an 30 amp fuse on the 24v line?

My 1165 has 12v power which has an 15 amp fuse, but I hope I can step that up to 25 or 30 amps without issue? If I use that as my line into the relay, it would already be fused.

And what’s the difference in continuous duty and not? Some relays note that in the description and others don’t.

 

[Mogman]

I’ll stop at O’reilys or autozone and hopefully one of the people there can help me get the right parts and maybe even walk me through the wiring.

But if I understand right, I will take power off the ignition switch (which is 24v) , put an inline fuse in, then connect to a 24v relay (which will act as a switch that simply turns my 12v stuff from off to on). So separately I will have a fused 12v line going into the relay, and then a load going out to my accessories.

FWIW I have the 200amp alternator. Idk what amps that puts out on the 12v side.

It seems that most of these relays are 30 amps? So I’d use an 30 amp fuse on the 24v line?

My 1165 has 12v power which has an 15 amp fuse, but I hope I can step that up to 25 or 30 amps without issue? If I use that as my line into the relay, it would already be fused.

And what’s the difference in continuous duty and not? Some relays note that in the description and others don’t.

You got it! the relay the 24V side only needs a 3A fuse to power the coil, the 30A part is the contact (12V) side, but only use enough fuse plus at least 20% that is required by the accessories, if you need 10A total (peak) then a 15 or 20A will be more than enough.
You of course have to spec the wiring and relay out to exceed the fuse size.

 

[Autonomy_Lost]

Also make sure the wire gauge is sufficient for whatever fuse you are using. There are charts you can look it up.

 

[thoner7]

Ok I’m on the right track, I just can’t figure the wrong diagrams on these relays. The one at this link has two good diagrams in the pictures :

https://www.amazon.com/PACK-AMP-Waterproof-Relay-Harness/dp/B074FSZWVT/ref=gp_aw_ybh_a_sccl_1/138-0255649-1876575?pd_rd_w=s0IEt&content-id=amzn1.sym.9720001e-8f8b-4ff3-adb5-e19707d971f6&pf_rd_p=9720001e-8f8b-4ff3-adb5-e19707d971f6&pf_rd_r=Y1AHH9KFQF85NNRSN4K7&pd_rd_wg=R0AgM&pd_rd_r=2b173a37-d43c-43ac-b5ba-e683a429f2f3&pd_rd_i=B074FSZWVT&psc=1

None of the diagrams show two power sources coming in(24v and 12v). ?

Also, how will I calculate the amperage draw I need to cover. There’s two 30 amp fuses on this thing I’m installing now

 

[Mogman]

Ok I’m on the right track, I just can’t figure the wrong diagrams on these relays. The one at this link has two good diagrams in the pictures :

https://www.amazon.com/PACK-AMP-Waterproof-Relay-Harness/dp/B074FSZWVT/ref=gp_aw_ybh_a_sccl_1/138-0255649-1876575?pd_rd_w=s0IEt&content-id=amzn1.sym.9720001e-8f8b-4ff3-adb5-e19707d971f6&pf_rd_p=9720001e-8f8b-4ff3-adb5-e19707d971f6&pf_rd_r=Y1AHH9KFQF85NNRSN4K7&pd_rd_wg=R0AgM&pd_rd_r=2b173a37-d43c-43ac-b5ba-e683a429f2f3&pd_rd_i=B074FSZWVT&psc=1

None of the diagrams show two power sources coming in(24v and 12v). ?

Also, how will I calculate the amperage draw I need to cover. There’s two 30 amp fuses on this thing I’m installing now

Well then you need to find out on how much power that device needs, ask the manufacturer, if it requires anything close to 60A you need to rethink the entire project as you cannot draw that much from the 14V tap, some say 30A max, I would not go over 25A. (30A fused)
If you need 30A or more TOTAL than you need an inverter and again I would suggest you seek professional help as it gets pretty complex done right.
That relay is a 12V relay and not applicable to this project.

 

[Mogman]

I also want to caution you about 24V circuits, if you ever shorted out something on a 12V system it may not have been a big deal, on 24V using the wrong size wire, fuse and or workmanship/design can be catastrophic, even just a dirty battery connection can boil the terminal off of a battery in just a few seconds.
So please be very cautious.

 

[Autonomy_Lost]

I also want to caution you about 24V circuits, if you ever shorted out something on a 12V system it may not have been a big deal, on 24V using the wrong size wire, fuse and or workmanship/design can be catastrophic, even just a dirty battery connection can boil the terminal off of a battery in just a few seconds.
So please be very cautious.

Yes, consider the fact that you can link two 12v batteries in series to make a functional welder, that will tell you what you're dealing with.

 

[Coug]

As i mentioned before, if you're going for more than about 30 amps fused (so less than that actual draw) I would say install the Orion 70 amp converter and follow the instructions for wiring it, as it has the built in relay that you can power off of any 24V circuit that's hot with the ignition on.
For stuff like this I tend to pull off the fan circuit like they did for the Red Dot systems.

(and if you need more than 70 amps, the Orion converters can be run in parallel, up to 5 of them for a total of 350 amps 12V power)

 

[thoner7]

Ok. I checked around and it seems that 13 amps is a good ballpark for power window motors. That’s each. So all four at the same time could be 52 amps.

 

[Mogman]

Ok. I checked around and it seems that 13 amps is a good ballpark for power window motors. That’s each. So all four at the same time could be 52 amps.

Your probably OK there to use the 14V tap, not likely going to use all of them at the same time and even then it is just an intermittent load.
In fact if that is all you are going to connect I would not even put a relay on it, just a good fuse at the place you tap the 14V, would it really matter if they would operate with the key off?
If so use a relay.

 

[thoner7]

Your probably OK there to use the 14V tap, not likely going to use all of them at the same time and even then it is just an intermittent load.
In fact if that is all you are going to connect I would not even put a relay on it, just a good fuse at the place you tap the 14V, would it really matter if they would operate with the key off?
If so use a relay.

Well eventually I plan to put a radio in, which would need to turn off.

With windows if they were all being put up at once, and hit the top and loaded out, you sure that’s ok? 52amps seams ridiculous to me as entire houses have 100 amp panels, but maybe it’s a volts thing- electricity confuses me.

 

[Autonomy_Lost]

Well eventually I plan to put a radio in, which would need to turn off.

With windows if they were all being put up at once, and hit the top and loaded out, you sure that’s ok? 52amps seams ridiculous to me as entire houses have 100 amp panels, but maybe it’s a volts thing- electricity confuses me.

Yeah amps is not total power, that would be watts. Houses with 100A panels are 240V which is 10x what a humvee is.

However, amps is what burns up wires and causes fires, so dont think its not a big deal only being 24V vs 240V.

That being said, I agree 52A seems pretty high for windows. It takes time for heat to build up in wires and you wont be actuating them for very long, so its unlikely you'll have issues unless the wires are way undersized.

 

[Coug]

The battery is there to act as a buffer/power reservoir, so having 50+ amps of load for short periods of time shouldn't be an issue as long as everything is functioning normally.