Dual alternator as a generator

Oops!! As a 7.1 PSD guy, I forgot about the modern DEF engines.

steve68steve wrote:
You'd have to put quite a few hours on it until you started realizing a savings over idling diesel (provided your diesel was already set-up to charge).

Big diesel engines (trains, ships, back up power generators, etc.) run/ idle continuously - or at least used to, unless they're brought down for service. Idling is child's play for a diesel.

Yeah, but one repair bill for a coked-up turbo will buy multiple Hondas.

Diesel pickup trucks are not locomotives or ships. They have very fussy emissions equipment on them nowadays. Anything made in the last 8 model years (2007-2014) came from the factory with the new emissions equipment.

A "150 Amp" alternator is not designed to run 100% duty cycle at 150 Amps. You'd burn it up running it at full output overnight anyway.

Starting from equal footing, where both systems would have to be set up from scratch, both will cost you about the same, but the generator will over time save you money on fuel and wear/tear on your truck's engine.

Hodag1 wrote:
I have a 2011 F350 6.7 diesel with dual alternators. Has anyone on this forum done this? Is there a source of premade cables and ancillary hardware to accomplish this?

I don't have a F350, but I do have a high output DC Power alternator in my RAM that is wired to the batteries in my TC with 2Ga cable. I regularly see 100+A charge current @ 14.7V from truck to camper when I drive or engage high idle (1100 motor RPMs)... so that's ~1.5kW with just one alternator. It seems reasonable enough, with a big budget, the right alternators, wiring, inverter, and a load to operate... that you could have yourself a 3.7kW "generator".

The real benefit of a high current (and/or dual) alternator set up is the ability to re-charge a large house battery bank very quickly while driving. Personally, I wouldn't choose to use my truck as a stationary "generator" on a daily basis, though I'd certainly high-idle the engine long enough to cook dinner in the microwave if I ever needed to.

With regard to the hardware you need to make it work;
- You will need a way to isolate the truck and camper electrical systems... You can use a simple high current solenoid or manual disconnect switch, or you can choose a battery isolator like the ones manufactured by Hellroaring. I went the manual disconnect route:


- There are several online businesses that will make custom cables for you, for example; Custom Battery Cables and 2X Power... but you can also go to a local reputable welding supply shop to get them made up.

- Assuming you intend to remove the TC from your truck from time to time, you'll also need a connector that is rated for the amount of current you plan to pass through it. Anderson PowerPole connectors are popular with TC owners, but I chose to use a 200A "lift gate connector":


- And finally, don't forget to install some circuit protection on each end of the cabling. VTE is a good source for fuses, fuse holders, and cable boots.

Cheers,
-Mark

Thanks all.I will send Earthroamer an email. Hopefully they will share. I already have the Xantrex 2000W 3 atate charger/inverter.

Wes Tausend wrote:
The 3.7 kWh claim seems a bit high. 3700watts/12volts = 308 amps, so such an output would require slightly over two 150 alternators run at maximum. What is the amp rating on the Ford alternators?

It's actually spot on. It's a normal Ford option called the Ambulance package. Nothing special. Each alternator is 160amps. They call it the ambulance package because it's standard on the ambulance chassis models.
They run a high end pure-sinewave inverter to run the medical equipment, as well as for redundancy.

Let's face it, it you're riding in the back of an ambulance and the alternator dies, there's a good chance you will too.

Boatycall wrote:

Wes Tausend wrote:
The 3.7 kWh claim seems a bit high. 3700watts/12volts = 308 amps, so such an output would require slightly over two 150 alternators run at maximum. What is the amp rating on the Ford alternators?

It's actually spot on. It's a normal Ford option called the Ambulance package. Nothing special. Each alternator is 160amps. They call it the ambulance package because it's standard on the ambulance chassis models.
They run a high end pure-sinewave inverter to run the medical equipment, as well as for redundancy.

Let's face it, it you're riding in the back of an ambulance and the alternator dies, there's a good chance you will too.

Yeah but we try not to idle them for prolonged periods of time. The rigs break down enough as it is. Last year on our E350 based ambulances 2 engines ( one gas, one diesel) one transmission. 2 alternators, enumerable elctrical wire chafes to the lines that feed the ambulance boxes, two egrs, one water pump, 2 ACs. There is a reason a lot of folks are moving away from the fords to sprinters for ambulances

Hodag1 wrote:
On the EarthRoamer site they say;
"We order Ford F-550 turbocharged diesel Power Stroke trucks with the dual alternator option which provides a quiet, fuel efficient, factory installed 3.7 kWh generator. We install an advanced battery isolation system and connect the factory alternators using low resistance, #4/0 tinned copper marine cable to the massive absorbed glass mat (AGM)camper battery bank. Whenever driving or the engine is idling, the AGM battery bank is being charged by the high output dual engine alternators. At idle, the Power Stroke diesel burns approximately .5 gallons of diesel per hour which is significantly less than many RV generators at full load."



I have a 2011 F350 6.7 diesel with dual alternators. Has anyone on this forum done this? Is there a source of premade cables and ancillary hardware to accomplish this?

0.5gph is a lot for 3.7kW. For comparison, my Kubota diesel generator (3.5kW) runs at 0.1 gph.

Also, those dual 185Amp alternators (which is what I think they are) would have to be operating at max load to make that much power. The motor is not going to be running at idle / 0.5 gph with that type of load on it.

A couple of other questionable things: automotive alternators rated at 160A will not produce that as soon as they get warm. And they will get VERY warm, since alternators are only around 60% efficient. Second, it would take a good quality AGM bank of maybe 800 AH to absorb 300 amps for very long. That's pretty big for even an Earthroamer. Since those are blank check vehicles, they really should be using LiFe batteries, if they have that charge capacity.

By the time you retrofit the truck, the stand alone generator is probably going to be cheaper to start with.

You are burning a lot more fuel than an equivalent generator.

You are putting more wear and tear on a device that costs tens of thousands of dollars to try and save a small number of dollars.

It's one of those things that sounds great until you dig into the details. I'm talking about using the truck as a stand alone generator. Beefing up the cables so more amps go to the house battery bank while driving can be a reasonable option but you likely aren't getting 300 amps to the battery bank and that would likely overload the battery bank anyway.