Engine speed for 200 AMP generator?

[mgFray]

Was wondering if anyone knew how fast the engine needed to be spinning for the 200 AMP generator, to actually output 200 AMP - 24V?

I'm assuming there is some sort of rule for shelter carriers or other similar high amp users to pulling the throttle out and having it enough to power various usages.

I've got a wild idea to buy a 24V - split phase inverter, hook it up via the NATO Slave port to the rig and use that either for camping or as a 'generator' for the house in the event of a power outage. Figure a 5000 or 6000 watt, 240V split phase would be enough power.. and is close to the 200 AMP - 24V (as long as I don't run it maxed out) that it would be able to power anything I need.

(I've looked at 240V split phase generators in the same wattage range, and none of them seems to be clear on power. They use the RPMS of the generator to handle the 60 Hz... an inverter would provide MUCH cleaner power, should it be needed.)

 

[Coug]

Some points to think about below.

So it's actually an alternator, not a generator. A generator is happy to pull 80% or higher load all day long no problems. An alternator won't be happy that high, and is much more likely to fail if operated under constant heavy loads for extended periods.

Ideally, you're going to only draw 1/3-1/2 of max load, which would put you in the 2k-2.5kw constant output range.

The batteries will act as a buffer if you use a larger inverter for surge loading.

The high amp draw trucks all use the 400 amp system, which has a smaller pulley and will do full output near idle.

So as to what RPMs you should run it under heavy load, probably around 1500 RPMs should give you plenty of power output. I don't know what RPMs are max output, but commonly in the civilian world max output is rated at 6k rpms, so you'd need to measure engine pulley and alternator pulley to figure out the ratio.

If it does fail, the cost will be much higher than purchasing an occasional use generator would, and if the generator fails, your truck will still be functional, unlike if your alternator fails. For the price of a good 6kw inverter, you should be able to buy a nice generator. A used Honda liquid cooled unit can sometimes be found in the $1k-1.5k range and are decently quiet for house use.

Another thing to consider is how close can you park your truck to your electrical system at your house? Are you going to mount the inverter in the truck, make it portable with slave cable hookup, or mount it in the house and run a heavy 24V cable out to the truck? Any way you slice it, copper ain't cheap.

For camping you're also better off with something like a small Honda suitcase generator if you need power. Or for half the price or less one of the off brands. Unless you're doing a LOT of camping and use a lot of electrical appliances, you really don't need the power. A couple USB outlets for recharging electronics cover most people's needs, or maybe a 500 watt inverter. For shorter trips you can buy pretty much anything you might need with built in batteries.

 

[TOBASH]

My only response would be that a small generator is a great idea, but I would consider a small diesel generator rather than a small Honda generator so you only need to carry one type of fuel

 

[mgFray]

Ya, I certainly misunderstood that it was a generator and thus had a higher duty cycle....

The big problem I have with traditional generators is the power is dirty between voltage and Hz. For a lot of usages that isn't a problem, but for motors (like a well pump), I'd be concerned it could cause damage if I had to use it for an extended period.

But with that said, 100 AMP @ 24V capability would still give me 10 AMP @ 240 (roughly). Certainly changes my thoughts on it though.. Thanks for the info.

 

[Coug]

compare pricing between true sine wave inverters and modified sine wave. Also a huge difference in cost, same as going between small gasoline generators and larger ones.

As for motors and clean power, they don't care much. Electronics and radios care about clean power, but motors, heaters, breakers, and many other items don't really care as long as the voltage and amperage are within design specs.

There are lots of off grid people that use cheap little generators at the well house to refill the storage tank, and run everything else of off solar and batteries.
Also, most modern generators are actually pretty clean power compared to what they were a few decades ago. A generator with an electronic type governor will be even more stable, but cost more.



In the end though, all I was trying to point out is in my opinion, the initial setup expense is much higher than other available options to accomplish the same goals.

 

[mgFray]

For me it's well pump, fridge, networking gear and computers. In the past I had a portable generator that fried my UPS, the voltage and Hz swings were just too much and killed the regulator in the UPS. (I work from home, so the computers and house not freezing in the winter are keys!)

I was looking at the 24V true sine wave inverters. 5000 watts is around $1000-$1500, my typical power usage is around 1500-2000 watts so would be good from a duty cycle point of view. (Note, I had originally assumed near 200 AMP generation was actually reasonable, which it's not.) As you mentioned, the batteries could buffer spikes (motor starts, etc), but I'm no longer thinking this is a good idea.

Someone asked about proximity to the panel. I live on a rural property, the main property panel, not on a building, has a manual 50 AMP transfer switch built into it. The utility pole it's mounted to is right off my driveway, which is what got me thinking HMMWV originally. The other option I have is a PTO driven generator, but I'm still concerned about the power quality, and that doesn't fix my 'I want it for camping and other projects where there may not be power!' problem.