by sunfun » Fri Aug 16, 2013 1:38 pm
An excellent point for using propane Snowball, yet I wonder if using solar and wind with batteries can provide reliable power for some campers that don't want to rely on propane fuels.
I can support panels with a frame (do it yourself) and as far as the power requirements goes, I feel like years of research into solar learning leaves me with a few uncertainties nonetheless. It appears that a 1000 watts system ought to cover my needs, yet I am not sure. I don't mind conserving on hot water heater or other items if needed, as long as food storage* stays good. The fridge and freezer (one chest freezer requires .50 kw each 24 hour period, and one chest freezer to fridge conversion .80kw) seem to take 1300 watts total daily. That is running 24 hours.
Therefore the fridge and freezer ought to run on solar during day (6 hours) and run off wind and batteries at night (18 hours). With wind production being an unknown factor to me, I can plan to count on the batteries for reliable night time use. So my query is how much battery amps supports 18 hours of fridge and freezer use?
Can anyone confirm this calculation? 1300 watts / 24 hours = 54 watts per hour I need to support x 18 hours of night time use = 975 watts. Also, I must allow for no sun days and battery charging which I can add in next but first are my calculations correct?
Can anyone agree on this calculation for battery power needed? If 975 watts is the overnight load to be supported by battery, and freezer and fridge use 120 volts, than watts=volts x amps 975= 120 x 8.125 amp, so is 8 amphours the battery power needed to run fridge and freezer overnight for 18 hours? If this calculation is correct, I can add in my other loads to figure out how much battery bank is needed. I just need to know if the theoretical battery amount is estimatedly correctly here.
And if I need 8 amp hour from batteries each night, do I need to double that so I don't use more than 50% of the batteries?
*This food storage system refers to chest freezer and chest freezer conversion to fridge. Both very economical food storage systems for boondcking for seasons at a time.
GE 8 cubic foot chest freezer $400 uses 292 kwh yearly. that is .80 watts in 24 hours each day. The conversion of one chest freezer to a fridge provides economical fridge at less energy use of regular fridge.