Talk:Kill A Watt

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Page move[edit]

I've moved the page from "Kill-A-Watt" to "Kill A Watt". This is because the product's name as per its website is "Kill A Watt". --AB (talk) 19:24, 6 February 2008 (UTC)

Unsourced claims about model 4460[edit]

The Sept 14, 2008 edit adds this line, "The 4460 adds a battery backup and data download port" however it is clear that P3I has not put out a Kill-A-Watt product with a data port. Is there a newer revision to this product, or does this line need to be changed? --Atamido (talk) 16:51, 17 September 2008 (UTC)

I've now reverted that edit. --AB (talk) 19:58, 17 September 2008 (UTC)

Claim about reading errors[edit]

The following paragraph was added, but it provides no WP:RS to support the major claims. (Source cited is a forum posting, no indication given that this is a common or significant problem.) Moved here pending better sourcing. Zodon (talk) 08:20, 10 April 2009 (UTC)

One significant problem with the Kill A Watt is that it has been observed to give falsely low power readings for power supplies with active power factor correction. Despite its 0.2% accuracy claimKill-a-Watt manufacturer product page, the Kill A Watt has efficiencies over 100% have been (mis-) measured.<ref>Image of Kill A Watt measuring 220 W AC power into a power supply that is providing 229.2 W DC power out into the load tester (bottom left). A second AC power meter indicates a more plausible 289 W AC (79.3% efficiency, 24% Kill A Watt error).</ref> The inaccuracy is commonly blamed on a low sampling rate for the current waveform.[citation needed]

Just FYI, it's been observed several times by several people (google the subject matter), but that forum posting was the most authoritative that I could find, being an actual photograph of the test equipment in operation. I can add half a dozen less-good sources (at least reports from several different people shows that it's not a single faulty unit), but what exactly are we looking for? It's not important enough news that the New York Times is going to do a write-up on the subject, so expectations have to be limited. 71.41.210.146 (talk) 21:23, 11 April 2009 (UTC)

Claim that this is a "significant" problem is not substantiated by the references. The blog posting is so terse that hard to understand, and impossible to replicate. (What were the devices involved, what basis for trusting the other power meter, etc. How widespread the problem is.)
If this is indeed a significant problem, why isn't it mentioned in any of the reviews of the Kill A Watt? (And if it is mentioned, then there should be better citations). Zodon (talk) 01:33, 12 April 2009 (UTC)

Well, you might want to take a look at the whole thread. Sorry, my citation was too specific; that was part of a dialogue that makes it clearer. Here are a bunch of discussions:

Interesting trivia I found while googling around: I see that Taiwan's "Prodigit Electronics Co., Ltd." appears to make versions with other power plugs:

Nobody's really tracked it down, but it seems to be associated with active power factor correction. Typical APFC circuits run a boost converter, providing a high-frequency (> 10 kHz) ripple on the input current waveform, and that might be confusing the Kill-A-Watt's circuits. —Preceding unsigned comment added by 71.41.210.146 (talk) 22:19, 12 April 2009 (UTC)

One more mention of Kill A Watt inaccuracy:
  • Enermax Galaxy Evo 1250W Review (2009-04-19) "The Kill-A-Watt was particularly useless this time... it was consistently wrong, especially in tests 5 and CL2. Thank goodness for that Brand meter."
71.41.210.146 (talk) 00:12, 24 April 2009 (UTC)

May store kWh, hours readings[edit]

I have a 2000MU, equivalent to the basic Kill A Watt 4400. Although the leaflet makes no mention of this, the kWh and hours reading are non-volatile and cumulative (i.e., it stores them when unplugged, for many months at least), although values can only be read when plugged in. The only way to reset these values is by holding down the Volts button. This was actually a nuisance until I worked out how to reset, I wanted to zero the kWh reading before measuing another appliance. It's fairly common for cheap Chinese devices to be quite different inside though with the same case and detailed part number, so I can't say whether this applies to all 2000MUs, let alone Kill A Watts. Absolutely original research, so not going in the article unless confirmed and sourced. Pol098 (talk) 19:47, 29 April 2014 (UTC)