semi-scientific experiment

[TrainChaser]

OP....   Would you mind posting your conclusion so that it's obvious to those of us (aka 'me') with poorly functioning mental processes in math and electronics?   Was the NuWave2 better or worse than your kitchen range?  Small words and short sentences are good.  Thank you.   (we also need an emoji with rolley eyes+shaking head+blush).

[Optimistic Paranoid]

OP....   Would you mind posting your conclusion so that it's obvious to those of us (aka 'me') with poorly functioning mental processes in math and electronics?   Was the NuWave2 better or worse than your kitchen range?  Small words and short sentences are good.  Thank you.   (we also need an emoji with rolley eyes+shaking head+blush).

The problem is, that I have no idea how much power the kitchen range used to boil the 4 cups of water.  So all I can say is that the induction cooker was faster.

Somewhere around here, I have one of the old style tabletop electric burners, which SHOULD have a sticker with watts or amps on it.  We used to use it when there was a power outage, running it off our emergency generator.  (My mother was deathly afraid of gas appliances.  She was certain that the house would blow up if we had a gas range or water heater.  So even during a power outage we couldn't bring a gas lantern or stove in the house.)

If I can find it this weekend, I'll run a comparison test on it, so I can say that it would have drawn X number of amp hours from the house battery, that way we'll be comparing apples to apples.

Come to think of it, I could also see how long it takes to bring 4 cups of water to a boil in our microwave. Then we'd have a three way comparison of both time and electric power.

I'll try to get this posted by next week.

[Scott7022]

Great idea I want to have all three, induction for water, micro for the forty-second reheat and virus nuke, and propane for BBQ. I figured Induction for water as it will be quicker but realized I pulled that out of the air with zero science. looking forward to it!!

[TrainChaser]

Looking forward to the results!

[Optimistic Paranoid]

Well, as promised, I found the old tabletop electric burner.  It dates from the 50s or 60s, I guess, and has a fabric covered two-prong non-polarized plug. (Danger Will Robinson!)

The label on the back was faded to illegibility, although the plate on the front said it was an 1100 watt unit.  But I have a Kill-A-Watt meter, so I decide to plug it in through that.  I also found an inexpensive digital kitchen thermometer, and my Android tablet has a stopwatch app.

So, 4 measured cups of cold tap water into a cold tea kettle.  Measured temp of the water was 71 degrees F.
 
Put the kettle on the burner and started the burner (on high) and the stopwatch simultaneously.

The wall outlet measured 121.1 volts at start, falling to 119.9 under load, and the amps measured 9.4 amps, dropping slowly to 8.9 by the time we were whistling.

Time:  8 minutes, 3 seconds.  I pulled the top off of the kettle and measured the temperature, it was 202 degrees F.  I’m GUESSING that means the thermometer is off by 10 degrees, or so.
 
Of course, I couldn’t put a metal teakettle into a microwave, so I measured 4 cups of cold tap water into a Corning Ware bowl.  It also measured 71 degrees F.

The microwave is a Sharp unit, marked at 1100 watts also (coincidence) and I also plugged THAT in through the Kill-A-Watt meter.  It also started at 121.1 volts, and fell steadily during the test, down to 118 volts eventually.  Amp reading started at 15.2 amps and eventually fell to 14.6 amps.

I ran the microwave for 5 minutes straight, then stopped it and measured the water temp.  It was 172 degrees.  I then ran it for another 2 minutes, and it only went up to 192 degrees.  Another 2 minutes and it was 199 degrees.  One more minute, and it was still 199 degrees.

I’m not sure what to make of all that.  Do microwaves become less efficient the hotter the item they are trying to heat is?  Five minutes to raise the water from 71 to 172, and then 5 more to raise it to 199?

Perhaps some of you, who have access to a microwave and a cooking thermometer, could repeat the experiment with 4 cups of water and report back here?  Don’t worry about the volts and amps.

Anyway, if we assume the thermometer is off by 10 degrees, then that 199 degrees was 209 degrees.  There were bubbles rising in the water slowly, but it wasn’t what I would call a “rolling boil”.  In any event, the water was definitely hot enough to make coffee, tea, or cocoa.

BTW, the 15.1 amps at 121 volts the microwave started out drawing calculates to 1827 watts and at 14.6 amps at 118 volts is 1722 watts.  So the 1100 watts marked on the microwave must indicated how much microwave power it puts into the food it is cooking.  It sure isn’t how much power it’s drawing from the wall outlet.
 
I decided to run the induction cooker again, once the tea kettle cooled, using the Kill-A-Watt, stopwatch and thermometer.

4 cups of cold water, measured temperature 69 degrees F.  Induction cooker on “High”.  Starting voltage 122 volts, falling to 119.6 under load.  Amp reading bouncing between 9.5 and 9.6 amps the whole time.

6 minutes 20 seconds to whistling.  Measured water temperature 199 degrees, which makes me certain the thermometer is off by probably 10 degrees.

Conclusions:

Induction Cooker:  9.5 amps X 6.33 minutes = 60 amp minutes
Electric Burner: 9 amps X 8 minutes = 72 amp minutes
Microwave Oven:  15 amps X 10 minutes = 150 amp minutes

Of course, 60 amp minutes = 1 amp hour.

So the induction cooker would use 1 amp hour from your battery bank.
The microwave oven would use 2.5 amp hours from your battery bank.
And the plain electric burner would use 1 and 1/5th amp hours from your battery bank.

These numbers all ignore inverter losses due to the fact that no inverter is 100% efficient.  And keep in mind, for a 15 amp load like the microwave oven draws, you would need a BIG battery bank, probably four 6 volt golf cart batteries wired together in series-parallel at a minimum.  And a pair of 6 volt batteries in series or two 12 volt batteries in parallel for the 9 volt loads.  Unless you have a LOT of solar panels, and only use one of these while the sun is shining.

So to answer Train Chaser’s question, the induction cooker is both faster and uses less energy than either the microwave or the plain burner.

Also, I happened to notice that when the induction cooker was plugged into the Kill-A-Watt meter, it was drawing 4.8 amps even when it wasn’t cooking.  If you left your inverter on, and left this induction cooker plugged in, it would use 12 amp hours from your battery every day while doing absolutely nothing!

I noticed the microwave oven was drawing power, too, even when it was off, but I didn’t note how much.  So neither of those should be left plugged in when you aren’t using them.  The plain burner didn’t draw any power when it was off.

Finally, I can also report that there is absolutely NO truth to the claim that a watched pot never boils!  This experiment clearly demonstrated that watched pots WILL boil!

[Seawolf1090]

Excellent lab experiment! Gotta love real world data!

[Snikwahjm]

I’d like to know how much the vitamix draws...

[Optimistic Paranoid]

I’d like to know how much the vitamix draws...

Sorry, I don't have a vitamix.  A Kill-A-Watt meter is only $20 at Amazon.

[Scott7022]

Errisson (yes correct spelling) Rated at 1000 watts But of course, this is plugged into 220. All the thermometers are metric as no one but the USA uses imperial measurements despite the whole T-party affair in Boston and not being part of the Empire...Well, I guess for accuracy it really isn't the Empire's Imperial system, just parts and the rest made up. Always had to explain why visitors got better gas mileage in Canada when we both used gallons. Finally, I just said we had better air. Anyway, I tossed 945 millilitres (4 cups) of water 73 degrees American into the microwave and cranked it to ten minutes and waited for it to visibly boil. Couldn't see it boil opened the door and steam flashover and bubbles. Tried it again and ran it for four minutes stuck in thermometer and 99.3 celsius 100 is boiling. Ran it a third time for four minutes and thirty seconds and tested water 101.2.

So we have an international test. Oh, and we are basically sea-level here. As altitude will, of course, influence the data.