Cooking With Alt-Power

- Coffee -


Okay, not technically "cooking", but many will consider this just as important.  When the grid goes down, how will you make your morning brew?  Go without?  Let's take a look at a few different machines and see how they perform.


A Conventional Cuisinart Coffee Pot


This Cuisinart coffee pot has an insulated pot, and no hotplate.  When it finishes brewing, the coffee stays hot all day, without reheating it.

Peak power was approaching 1000 Watts.

Total power used to brew a full pot, 0.16 KWH, or 160 WH.

Total time to brew, 15 minutes.

Most coffee pots keep the brewed coffee warm by constantly warming it with a hotplate under the pot.  This wastes energy, and doesn't help the quality of the brew.  This particular coffee pot is very well insulated.  Any leftover coffee at the end of the day is still hot enough to drink, despite not being reheated..  160 WH / 12 V = 13.3 AH from the battery bank.  Note that this was for a FULL pot, not merely a single cup.


A Keurig Single Cup Coffee Pot


On the left side of the machine is a water hopper.  About half full in this picture.  Inside the machine is a tank that keeps about a quart of water hot all the time.

During the periodic reheat cycle, it draws about 460W.  When called upon to brew a cup, the power spikes a lot higher.

Since the water is already hot, the brew time is a matter of seconds.

It also reheats the water very quickly.  About the time you can swap the cup, and the pod, it's ready to go again.  Nice machine for an office environment.

The Keurig coffee makers are intended to brew a single cup at a time.  By looking at the numbers, it appears to be a much better way to go.  That's true as long as you turn it off when done.  Otherwise it keeps reheating the water in the reservoir periodically.  Only 0.01 KWH, or 10 WH.  10WH / 12V = 0.83 AH.  That's pretty good, but what you didn't see is this had been heating the water periodically all day.  In the long run, this one uses more power than either of the other two.


A Keurig Mini Coffee Pot


The Keurig Mini is intended for travel.  We bought the optional carry bag, which has enough room for the coffee pot and a box of coffee pods.  Unlike the full sized model, it does not have a water reservior.  Pour a cup of cold water in the top, put in the coffee (tea, or even hot chocolate) pod, push the button.  A minute and a half later, it's done.  Unplug it, no parasitic load.  Total power to brew a cup, 0.02 KWH, or 20 WH.  20 WH / 12V = 1.67 AH.   


You could certainly brew coffee the old fashioned way, with a fire, on top of a fireplace, on a grill, etc.  But those use resources you might not have during an outage.  This is so easy and convenient with an inverter connected to a battery bank.  My lead engineer also has a Keurig Mini, and brews coffee while traveling.  He put a battery and inverter in the back of his pickup truck.  Fresh coffee everytime they stop.  The battery is recharged each time the engine is started.  We often take ours when camping (okay, RVing).  Who says you can't have coffee when the power goes off?


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Last updated 04/05/11    All rights reserved.