LAST EDITED ON Jul-24-04 AT 04:12 PM (EST)LAST EDITED ON Jul-24-04 AT 04:07�PM (EST)
LAST EDITED ON Jul-24-04 AT 03:25�PM (EST)
I just read what I wrote earlier, and thank God you can understand jibberish.
You have the right idea, HOWEVER...
What I am attempting is to eventually use the DR's as primary power (eventually - other elements are in the works) with the gen-set for battery charging. For now, if I can get the DR's set up the way I want, I can use a 30A relay to switch the battery charging function from the grid to the gen-set whenever the gen-set is started. Thus, the DR's will be short-term backup (up to several days) for the grid until I start the gen-set when I get home. Once started, the gen-set will continue running and charging the batteries until either they are fully charged, or the grid comes back on line. At that point it will shut down.
The power drain from the DR's will be continuous whenever I'm off the grid (i.e. during power outages), but not constant. For the most part, I don't use very much power...mostly just the furnace blower motor and the occasional repressuring of the well. When I'm gone, all I want the system to do is to protect the trailer from freezing in the winter and to keep the well primed.
However, when I'm home for several hours (or on the weekend), I'm doing laundry (both washer and dryer) as well as showering. If the power goes out during this time, I need a larger output capability to keep everything up and running until I finish showering or whatever activities I'm involved in.
Remember, I drive truck. It is often the case that I leave for work immediately after completing these activities.
If I have significantly drained the batteries, and the grid is still off line, the batteries have to be charged back up, and the generator will handle this during the low power drain period that I am gone.
The primary advantage of the system using a smaller gen-set is that there is far less wasted energy going out the exhaust as would be the case with a larger gen-set. I know several people who use large gen-sets of 7 KW and more, and when the power goes out, their fuel usage is horrendous. It is far less expensive to operate a DR @ 80% efficiency than to use a gen-set at 10% efficiency.
No, I haven't asked Trace. Every time I talk to some company about modifying some of their equipment, they freak out, try to dissuade me and then never do answer my question. After that, I usually find someone who has already pulled off what I want to do, so I figured I would forego their inevitable freaking out.
Besides, it looks as if Exceltech has solved my dilemma even as we communicate. They have a brand new true sine wave inverter system that is n+1 expandable up to 20 KW on 120v single phase and 40 KW on 240v bi-phase (what a strange term). Unfortunately, it's a bit more salty. Oh, well...