3 tons wrote:
StirCrazy wrote:
3 tons wrote:
I have a similar set-up (at 400a/h LFP and 660w) and get the temptation but in the vagaries of the real world harvest, not too sure it’ll always pencil out -
In theory something like this: a gallon of propane has about 91,400 BTU’s, while 325w (ac power) at say a more conservative 75% duty cycle (considering local and inverter losses…) would equal 5850w over 24hrs equals 15.6 hrs refer operation per gallon of propane or 78 hrs per 5 gal tank…Just saying…
3 tons
Im not sure what your trying to say, but my fridge in my camper is a old one where the burner stays on all the time and I can easily let it go 3 months running 24/7 on a single 5 gal tank. once I start it up in the spring it stays going all summer until I winterize it in the fall, so three years now it has done this. I do this with my 5th wheel also and same thing, I fill my bottles in the spring and they don't get filled untill winter when I am doing inclimate camping. the 5th wheel does have a DSI large fridge, but it has 7lb bottles.
Well, in retrospect it does seem oddly high but was only a rapid back of the napkin calc..
However, I believe converting BTU’s into watts is the proper way to draw conclusions…
3 tons
Im not sure, I think the electrical elements are way more power then the system needs and are sized that way because its a contact transfer and only part of the heating element is making contact with the piping. A flame gives you a much more efficient localized heat transfer so it doesnt need as many BTUs, but I am not 100% positive thats the reason. I know with my tent trailer, my old 29 foot trailer my 5th and my camper every one would go all summer running the fridge only on propane and not use up 1 20lb bottle. might be somthing interesting for me to dig into a bit. I am almost wondering now if you could redesign the electrical element could you get more efficient transfer and lower the amount of power used.. my little 2510 dometic in my camper just has a little pilot flame that burns constantly , but on 12V power it is up over 11 amps.
Steve
