XR4rider wrote:
I was wondering if someone can help me do the math for running a Keurig mini single cup coffee maker off batteries. The Keurig says its 1400W. The machine, when plugged in, takes about 3 minutes to make a cup of coffee. I have a 2000W inverter to 2 6-volt batteries (225Ah). I also have a 100W solar panel on the batteries as well. I've been reading some watt-amp-amp hour formulas but get a bit confused. I am wondering if making a cup of coffee in the morning will be harmful to the batteries. During the day we do not use any power so the panels help re-charge the batteries, plus I do have generators that I can run to help re-charge. I feel I have enough time in the day to put a good re-charge to the batteries...but my concern was using the Keurig will deplete the batteries to a point where they wont re-charge or hold a charge. Thanks for the input.
I have the same Keurig as you, two 6v batts, a 2000watt ProSine 2.0 inverter and solar, so can offer you a bit of apples to apples real world experience specific to your scenario.
Per on board LinkLite metering, a cup of coffee draws approx 122 d.c. amps, but only for about 2 minutes then drops off to about 60 amps during the final minute, for a total of 3 minutes operation. A coffee maker is purely a resistive load, not nearly a severe as the somewhat inductive load of comparable wattage microwave ovens.
Battery state of charge in percentage (SOC) drops off only by about 2% of total amp/hrs per each cup brewed (note, LinkLite meter is programmed at a conservative 200 amp/hrs). I typically brew two cups back to back and sometimes a third and have never had any kind of battery or inverter problems for more than 7 years running....A bigger concern in my view would only be to make sure your cables to the inverter are sized sufficiently for the high amperage brief load - I'm using 4 ought. Other than that I might suggest another 100w panel for a quicker recovery.
