Power Converter Question

[csheath]

I am wondering if one of you brainiacs can answer a question for me.

I have a tractor with a 12 volt AGM battery rated at 540 cranking amps and a 55 amp alternator.
I want to connect a 750 continuous, 1500 max watt power converter and run a 500 watt load at 120 volts on it.
Would my battery and charging system hold up under that condition?

 

[DieselAddict]

I'd say that won't quite cut it. 55 amp @ 13v is just over 700w. Your 500w load will draw ~600w of input power to the inverter. In my opinion that doesn't leave enough overhead to maintain the battery or any other power loads on the vehicle. It won't be good to run the alternator at max output for long periods either.

 

[Coug]

I'll second the above. You really don't want to run an alternator near max continuously.

Depending on what type of tractor it is, you might be able to swap out the alternator for one with a larger output.

 

[csheath]

Thanks for the replies. I kind of figured as much but didn't know if the numbers I was finding on the intenet were accurate and wasn't smrt nuff too figure it out for myself.

 

[Triple Jim]

What is the 500 watt load?

 

[Scoobyshep]

runable but not recommended.

for future reference P/I*V. In your case 55*13= 715watt. this leaves 215 watts for the tractor and tractor accessories IF you run full load. Rule of thumb for continuous is 80%.

 

[MarkM]

What are you running that draws a constant 500w draw?

Mark

 

[csheath]

Was thinking about running a 5000 BTU AC unit. Actual draw should be below 500 watts. Probably 1000 to start it briefly. The inverter I was considering is rated for 750 continuous with 1500 intermittent.

I could probably mount a 2000 watt generator to run it. Fuel consumption on a 2000 watt inverter generator is about 7 hours per gallon.

 

[nextalcupfan]

Was thinking about running a 5000 BTU AC unit. Actual draw should be below 500 watts. Probably 1000 to start it briefly. The inverter I was considering is rated for 750 continuous with 1500 intermittent.

I could probably mount a 2000 watt generator to run it. Fuel consumption on a 2000 watt inverter generator is about 7 hours per gallon.

Sorry to inform you but the startup on that AC is probably 4-5x the running watts.
If you get me a pic of the data plate I could probably give you an accurate number.

Also in general inverters REALLY don't like a big spike in inductive load. (Motors and compressors)

Unless your AC has a "Soft-Start".

 

[DieselAddict]

Starting an AC is pretty tough on an inverter. I'd say to try it but don't be surprised if it can't kick the AC off. If you have one of the inverter based ACs they are a totally different story. They ramp up slowly and don't put a heavy surge on the inverter. I bought one for the house to use in the summer for auxiliary cooling and it works great on the inverter here. Its a 16kbtu 120v unit.

Even so I'd recommend against using DC power from the tractor. I don't think it will be good for its long term health.

 

[nextalcupfan]

My recommendation is buy a cheap tractor PTO generator.

 

[kloppk]

If you looking at a High Frequency inverter then it's way less likely to be able to start it. HF inverters can only put out their surge capacity for a very brief time before tripping.
On the other hand Low Frequency inverters are much more suited for starting motor loads. They can put out their surge rating for an extended period.

 

[DieselAddict]

If you looking at a High Frequency inverter then it's way less likely to be able to start it. HF inverters can only put out their surge capacity for a very brief time before tripping.
On the other hand Low Frequency inverters are much more suited for starting motor loads. They can put out their surge rating for an extended period.

The way to know the difference is if you can pick it up without causing a hernia then it not a low frequency inverter!