The Amazing “Kill A Watt Meter”

It’s a tool designed around one of the principle philosophies of utterpower, do your own math!

The Amazing Killawatt Meter

>>> Buy a Kill A Watt Here

I’ve mentioned this handy and inexpensive device many times, it gives the DIYer a very inexpensive method to monitor Voltage, Current, Frequency, Kilowatt hours, and Power Factor, Few of us need much more, and at a cost of twenty five dollars or less, it is very difficult to pass up as your power monitoring display(s). Sure thing; a beginner starts off wanting those cool looking analog meters for each display, but at some point you learn the downsides whether it be cost, breakage, ease of replacement, lack of features, flexibility or more.

A Current Transformer is easy to find, some at surplus prices

Your hands on experience will build an appreciation for the killawatt, inexpensive enough to have spares on hand. Plug one in where ever you want to monitor your power, the kitchen, the shop, add ONE external component, and get total load information at your generator head, or at the first distribution box.

Thanks to DIYer and PE ‘Bill Rogers’, the killawatt has been tested with a Current Transformer than can extend it’s range in reading current and tracking total kilowatt hours. There will be very few serious off grid power producers that will find a need for more monitoring information, accuracy, or data collection than what the kill a watt provides.

If you watch the forums, you’ll soon see things like a person posting that he’s carrying 10KW of load with his modified DIYer 12 horsepower engine and gen head. All he did was change the compression ratio and add some of those new trick racing valves, and he’s now offering to sell you the modification and knowledge. The odds are high that he has deceived himself, he hasn’t yet learned to measure AC power with any accuracy. KVAs and KWHs are very different things. The formula for figuring AC power is not E times I as the poster likely calculated. Lucky for you, the killawatt is smarter, and it will produce running totals and even show you that all important power factor. Reality is an important thing for the true DIY Power Producer.

Let me give you a real world example of the value of the killawatt. Consider a Xantrex Inverter with a built in Charger. You read the manual and become impressed with the efficiency rating of these chargers (as you should). But you may walk away with the thought that this high efficiency is across the board. If we look at that big transformer core in the older and reliable Xantex, just what do we expect for efficiency if we are using the grid or another source of AC power to keep our batteries in float? Let’s get some hands on experience with the killawatt right now and give it the task of answering our question. With the batteries in float, we’ll ‘lockout’ all AC loads or turn the inverter section off. This will assure we don’t pull more current through our unmodified killawatt than it was designed for, and since we are studying what it takes to float the battery, we’ll be looking at power well within the range.

First we find the AC input to the charger, this may go over to a wall style plug where we see commercial power when it’s available. for off girders, it’s likely your generator output. if you are already wired this way, the study is easy, just pull the plug out, plug the killawatt in, and then plug the charger back into the front of the killawatt. With the batteries in float, push the button on the front of the killiwatt for power factor. Do you see a dot six or similar, not all that pretty huh? Now let us look at the power and compare it to the current into our batteries and then calculate the power in and the power out to the batteries. What you may find is that you are using about five times the energy to float your battery bank as a purpose built charger might use. We might see this set up in on grid installs where the inverter system is back up, if you are paying 8 cents a KWH, you may not care, if you are paying 40 cents, you may be motivated to make changes. If we look at the cost over a year, it all adds up. Locating that purpose built charger on sale or at surplus prices might be an easy thing to do. Of course, this is only an example and you will find lots of studies and experiments to conduct, especially inductive loads of all sorts. A refrigerator is full of surprises, and the mods you can make for greater efficiency and to reduce the burden on your power plant are numerous and fun. This might be an excellent topic to cover in the near future.

>>buy Kill A Watt here

All the best,

George B, Utterpower.com

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3 Responses to The Amazing “Kill A Watt Meter”

  1. rob cullen says:

    Gday George B. Hey mate just wondering if you know if there is a 240volt version of the kill a watt available and if so where i could source it. Im rebuilding a 1945 cs-6 with new st-3 gen. cheers rob .perth australia.

  2. NOKAYA says:

    YOU CAN USE A 120V KILL A WATT ON A 240VOLTS SYSTEM BY CONNECTING A STEP DOWN TRANSFORMER FROM 240V TO 120V. CONNECT THE 120 VOLTS SECONDARY TO THE KILL A WATT INPUT OUTLET.. A MODIFICATION ON CONNECTION SHOULD BE DONE BY CONNECTING THE NEUTRAL PORTION IN PAIR WITH TH OTHER 240 VOLTS TERMINAL.. THE READING SHOULD BE MULTIPLIED BY 2 AS THE REFERENCE VOLTAGE IS 120 VOLTS.. TO BE MORE ACCURATE, YOU HAVE TO TEST THE VOLTAGE ON THE 240 VOLTS AND THE 120 VOLTS TO GET THE ACTUAL RATIO.. (IT MIGHT NOT BE EXACTLY 2 240/120). ANOTHER WAY OF DOING THIS IS TO MODIFY THE TRANSFORMERLESS POWER SUPPLY SO IT WILL LOOK LIKE 240 VOLTS AND TEST IT WITH A STANDARD KWH METER TESTER SO YOU CAN HAVE A MULTIPLYING FACTOR ON ACTUAL ACCURACY. THIS MIGHT NOT BE UL STANDARD BUT GOOD ENOUGH

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