Compact Refrigerators

small fridge running off a 600ah battery for camping trips?

how long approx would a small countertop fridge (rated at 0.8kw-h/24h) run off a 600ah car battery with a 2000w inverter ? Would it be worth getting a 40w solar panel to charge the battery - or would that not be enough?

Public Comments

1. too late in the day for me to do the maths, but the solar panel is a waste of time, Your fridge uses 800 watts so how will a 40w solar panel charge the battery quick enough? (it cant) But are you sure about your fridge using 800w? sounds more like a small heater did you know you can also get gas fridges for caravans (no, i am not joking)
2. NOTE: Poster is in UK, AC is 220V NOTE: Estimate total inefficiency at 0.75 Normalize:0.8KW/H = 800W/Hr Calc for day:800 * 24 = 19200W/Day Convert Amps:i=p/e, 19200W/220V=87.3Amps/Day Inefficiency:pf=0.75, 87.3 / 0.75 = 116.4Amps/Day Assuming a deep cycle 600A/Hr battery and no more than 75% depletion to avoid premature battery failure, you could run the fridge for 600 * .75 / 116.4 = 3.8 days without a solar charger. The 40W solar charger only provides 5% of the power required to run the fridge, and assuming 16 hours/day of full power output, would theoretically extend the operational time to about 4.1 days. But 600A/Hr would be a honking-big battery. Standard automative starting batteries are not rated in Amps/Hr, but rather in CCA -- Cold Cranking Amps -- the amount of power that can be supplied in a short period to start a car. These batteries are not designed to provide long-term power supply, and their performance in such a situation will be very poor. Better for the application would be a Deep Cycle battery. But standard size Deep Cycle batteries put out around 80-120AH, and following the 75% max discharge rule, neither would run the fridge as calculated above. The next issue is whether the fridge really consumes 800W/Hr, or whether this is variable depending on how frequently the compressor cycles. I have no way to tell without access to your fridge and the conditions where you expect to camp. How to overcome these obstacles: * Extend runtime by connecting 2 or more batteries in parallel * Recharge from car, generator or shore power * Use a lower-power 12V/DC unit, such as from Engel, ARB, Coleman * Use a 2-Way/3-Way RV fridge that can run off Propane, AC or DC