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24 volt alternator ( auxiliary )

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HarryN

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I have been involved in some van projects where we added 24 and 48 volt alternators.

The 48 volt work, but it can be a lot more complex than 24 volt versions due to products availability.

Since my auxiliary battery pack will be 24 volt, gathering together info on what it takes to add on an after market alternator on the 25+ cummins / 3500.

The reason is that it is fairly easy to get 3 kW from a 24 volt alternator and much easier to move it around.

Right now just gathering information.

Thanks

WARNING - This is just information gathering and some of it will not be correct. Please double check before using anything and feel free to contribute anything related to the OEM setup for p/n's etc as this will lead to other parts, brackets, etc.
 
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I have a 2024 Rebel 6.7 and it has 2 alternators. It was an option. Now I am trying to figure out how to harness that DC power for my RV trailer. What I mean is the wire with constant power on the 7 pin trailer connecter is maybe a 12 gauge which would limit the current going to the trailer to about 20 amps.
 
Haggs said:
I have a 2024 Rebel 6.7 and it has 2 alternators. It was an option. Now I am trying to figure out how to harness that DC power for my RV trailer. What I mean is the wire with constant power on the 7 pin trailer connecter is maybe a 12 gauge which would limit the current going to the trailer to about 20 amps.
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The wire in the 7 pin connector are just not useful for moving significant power from the truck to the trailer. I can run the math for you but you are right that it just is not useful.

If we target moving ( 100 amps ) x ( 12 volts ) ~ 1200 watts using DC - DC chargers, then the absolute minimum wire size ( reading from the left column of this ampacity charge ) is ~ 2 awg. This is possibly feasible, but disconnecting a live DC wire like that is - not ideal. The spark is substantial and can be quite damaging.

A more common approach is to use 120 vac, so 10 amps can easily be carried by 10 awg wire.

So put a 1500 or 2000 watt inverter in the truck, and run the wire to the RV trailer. Many trailers have a 120 vac charger in them that can be used to charge the battery.

This approach is very common in the van up-fit world that I play in.

Most consumer inverters are rated for "occasional duty" vs "continuous duty" so it is important to substantially oversize it.
 
Haggs said:
I have a 2024 Rebel 6.7 and it has 2 alternators. It was an option. Now I am trying to figure out how to harness that DC power for my RV trailer. What I mean is the wire with constant power on the 7 pin trailer connecter is maybe a 12 gauge which would limit the current going to the trailer to about 20 amps.
Click to expand...

It probably is not easy, but if you can get any photos of how the dual alternator it is implemented that would be interesting.
 
Haggs said:
I have a 2024 Rebel 6.7 and it has 2 alternators. It was an option. Now I am trying to figure out how to harness that DC power for my RV trailer. What I mean is the wire with constant power on the 7 pin trailer connecter is maybe a 12 gauge which would limit the current going to the trailer to about 20 amps.
Click to expand...

Most common approach is to run a separate set of cables to the RV with an Anderson style disconnect at the bumper and then use a larger DC-DC converter.

HarryN said:
It probably is not easy, but if you can get any photos of how the dual alternator it is implemented that would be interesting.
Click to expand...

What do you want to know? There isn't much to learn from a photo with how they are integrated. Pass alternator has the field wire coming from a wire harness on the pass side and feeds directly to the pass battery, the 2nd alternator is on the drivers side and has it's field wire from that side and ties into the drivers side battery. Not much to it, both are ECM controlled.
 
AH64ID said:
Most common approach is to run a separate set of cables to the RV with an Anderson style disconnect at the bumper and then use a larger DC-DC converter.



What do you want to know? There isn't much to learn from a photo with how they are integrated. Pass alternator has the field wire coming from a wire harness on the pass side and feeds directly to the pass battery, the 2nd alternator is on the drivers side and has it's field wire from that side and ties into the drivers side battery. Not much to it, both are ECM controlled.
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This is what I do. My trailer system is 24v so I’m running a Victron Orion XS1400 in the trailer because it can do any 12 or 24v on either side at a max of 50A. There’s a 2AWG run from my truck battery to the Anderson connector on the bumper, and at the Orion it hits a fuse block that drops it to 4AWG as that’s the largest wire that fits in the Orion. It also leaves me room to add a second Orion if I want to send 100A back there.

In the summer this thing cranks out all day long at 50A as I run the trailer ACs off of my battery when I drive. I also highly recommend the Orion XS models as they’re extremely efficient. There’s only a 13W loss at 700W throughput, so it never gets hot enough that you can’t put your hand on it. Find an inverter setup that’s anywhere close to that efficient.
 
jsalbre said:
This is what I do. My trailer system is 24v so I’m running a Victron Orion XS1400 in the trailer because it can do any 12 or 24v on either side at a max of 50A. There’s a 2AWG run from my truck battery to the Anderson connector on the bumper, and at the Orion it hits a fuse block that drops it to 4AWG as that’s the largest wire that fits in the Orion. It also leaves me room to add a second Orion if I want to send 100A back there.

In the summer this thing cranks out all day long at 50A as I run the trailer ACs off of my battery when I drive. I also highly recommend the Orion XS models as they’re extremely efficient. There’s only a 13W loss at 700W throughput, so it never gets hot enough that you can’t put your hand on it. Find an inverter setup that’s anywhere close to that efficient.
Click to expand...

I've only ever read good things about the Orion XS. If I wasn't installing a 24V alternator on my van (it gets here tomorrow :p) that's the route I would be going.

I thought that the output was limited to ~25A when going 12 to 24V due to the 50A inlet limit, and the only way to get 50A @ 24V was to go 24-24. Are you seeing 50A 12-12?
 
AH64ID said:
I've only ever read good things about the Orion XS. If I wasn't installing a 24V alternator on my van (it gets here tomorrow :p) that's the route I would be going.

I thought that the output was limited to ~25A when going 12 to 24V due to the 50A inlet limit, and the only way to get 50A @ 24V was to go 24-24. Are you seeing 50A 12-12?
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It’s 50A max in or out. So 12/12 you get 50A in and out at 12V (really 14V nominal, so 700W), 24/24 you get 50 24V (really 28V nominal, so 1400W), 12/24 you get 50A in at 12V and 25A out at 24V, 24/12 you get 25A in at 24V and 50A out at 12V.

I ran the plain Orion XS 12V only model for over a year in the last trailer and it did great as well.

I should also add that my 12V stuff in the trailer is running off an older Orion 24/12 70A converter. It’s rock solid, but less efficient than an Orion XS and provides no data. It was also less than half the price.

Rumor is there will be a 70A Orion XS coming out soon.
 
jsalbre said:
It’s 50A max in or out. So 12/12 you get 50A in and out at 12V (really 14V nominal, so 700W), 24/24 you get 50 24V (really 28V nominal, so 1400W), 12/24 you get 50A in at 12V and 25A out at 24V, 24/12 you get 25A in at 24V and 50A out at 12V.

I ran the plain Orion XS 12V only model for over a year in the last trailer and it did great as well.

I should also add that my 12V stuff in the trailer is running off an older Orion 24/12 70A converter. It’s rock solid, but less efficient than an Orion XS and provides no data. It was also less than half the price.

Rumor is there will be a 70A Orion XS coming out soon.
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Ok, that's what I was thinking. When you said it cranks out all day at 50A I was thinking you meant output, which didn't make sense for 12-24.

I am pretty sure a 70A unit would sell very well.
 
AH64ID said:
Ok, that's what I was thinking. When you said it cranks out all day at 50A I was thinking you meant output, which didn't make sense for 12-24.

I am pretty sure a 70A unit would sell very well.
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Yeah, I can see how my wording was confusing.

If a 70A version comes out I’d be tempted to swap out my current one. Of course, with 1200W of solar on my roofs with plans for more, and Furion Chill Cubes for ACs I’ve barely needed the 50A.
 
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