When I ordered my F 250 in 2015 i purchased the 67D 200 Amp upgrade.
I plan to run a 2000Watt inverter off the battery.The question is.
What engine RPM to get the 200 Amp output to the battery ??
Plan to run truck camper A.C going down the road.

Thanks

 

Assume your alternator puts out at the normal (~14.2 VDC) 14.2*200 = 2840W at ~1200 engine rpm.

You should assume circuit losses of at least 5% and more likely 10% for your inverter, so your 2kW inverter will actually need around 2100W - 2200W (minimum) DC to output 2kW AC.

That only leaves you 640W to 740W or between 45 and 52 Amps to recharge the battery, and run all of your other electrical loads.

While it may work, I strongly suspect that you will have a very short life on that alternator.

 

this is basically correct......but also consider the voltage drop across both the alternator and the battery.....you will always be discharging both...unless you put in a battery isolator.

 

Thanks Guys for the input
I would only be using the A.C.on the camper a few hours at a time,maybe 10 - 20 days per summer.Like when we are camping off the grid.The other choice a portable generator.Then have to mess with gas cans ,noise,and smell.Is the lifetime of an alternator dependent on load ?

 

HEAT,
brushes
bearings/bushings

and gas mileage. nothing is free..

did I say Heat... !.

heat in alternator.. inverter, wiring.... lots of power wasted in heat.
long stop lights might be a problem...

 

Ah, the age-old question when it comes to powered accessories - to drive them from a common power source, or self-powered? In almost all cases from wood splitters to generators, I've found that self-powered is usually better. Unless you really need the power of something like a 50hp tractor for a 25KW generator, the convenience of having a self contained unit wins. And the economy. In your case, the trade-off of hauling a standalone generator vs. the fuel of running a truck engine to generate 2kw of power is worth considering. You can buy a 2kw inverter generator about the size of a 5 gallon can for under $500 - that would be my choice.

 

Also remember most portable generators are listed at their peak wattage or surge load capacity not their running or constant load capacity. For what you are looking for I'd suggest something in the 3500W range, and that will give you a bit left over to run the tv, coffee pot, microwave etc. The Predator series from Harbor Freight is pretty highly rated. I've got an 8750 and I'm really happy with it. They've got a 4kw Surge unit (3200W running) for $299.99 that would probably suit your needs pretty well.

 

I would highly recommend an inverter generator for this application, even though they are a little more pricey. If you're like me the last thing you want is the constant roar of a generator in the background making noise and burning lots of fuel even when you are using almost no juice!

 

I have had inverters on my last 3 trucks, I have a 1200 watt inverter to recharge batteries and also have a 6000 watt inverter to run a 2 hp air compressor, and also power saws and such. I have never had an alternator failure and the batteries hold up fine. I would imagine it is not the wattage rating of the inverter, but the amperage draw of the load plugged into the inverter that would load the alternator. Also my last two trucks had the 110 amp alternator and it did fine. It also depends on the quality of the power inverter and your batteries in the truck, I always run the highest amperage rated batteries on my last 2 I ran the 1000 amp rated batteries but on my new truck only the 800 amp batts will fit. Remember the inverters are rated at peak output and if you are running a heavy load like your a/c in the camper you will need 2 to 3 times the watts to start the compressor. I also have a whole house generator that has run for weeks at a time and find that the microwave oven uses a f-load of wattage so if you want to run your camper I would just get a decent generator. I also have a 2500 watt inverter on my boat and I had to put a hard start kit on a small window unit a/c to get it to start with it, but the batteries have to be fully charged. Some inverters have a slow start up function also which does not work well with heavy motor loads. You will also need to run very heavy power leads to the inverter so keep that in mind. Hope this helps.