Anybody know anything about Kill-A-Watt failures?

Big Brother sent me that one a few years ago, and he had had it for some years before that so I don’t know how old it is. I kept it in the powershed for occasional use until a few months ago but got tired of having to shuttle it in and out of the Lair. Since I always used it at the same outlet and it uses next to no juice I finally left it plugged in. That was apparently a mistake: I noticed yesterday that it no longer displayed and I can’t figure any way to get it to change its mind. I’m afraid I’ve killed it.

They’re less than $20 on Amazon so it’s not an irreplaceable family member. But very useful when you’ve built your own off-grid power system and need to pay attention to watts. I definitely want to fix this one or get another just like it.

If this is a known phenomenon and there’s a known way to bring it back to life, I’d appreciate somebody lending me a clue. But right now …

About Joel

You shouldn't ask these questions of a paranoid recluse, you know.
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8 Responses to Anybody know anything about Kill-A-Watt failures?

  1. LibertyNews says:

    I haven’t had any problems with the one I’ve had for, I think, 6 or so years at least. It’s possible that it doesn’t play well with your inverter, but that’s just speculation since I only use mine with grid power.

  2. Malatrope says:

    Mine has a battery in it that runs the display and sensing electronics. It looks like you have the same model. Just take it apart and replace it (probably means a trip to town so, as Amazon would say, “it’s an add-on item”).

  3. Ben says:

    That’s interesting! The KAW brochure clearly advertises that the unit has a backup battery, but the operation manual says nothing about changing it. There are multiple UTube videos about replacing the thermal fuse inside the KAW, but unless you have done something to overload it, that is unlikely to be your problem. In the end, it’s only $20,00.

  4. Jim Price says:

    I have exactly that model, the KAW P3. I have had mine apart and I can assure you there is NO battery inside. These things don’t store or retain any information, so there is no need for a backup battery.

  5. Mike says:

    You killed a Kill-A-Watt, shame on you… At a guess, since I have very little knowledge of how these work, could it have been a power surge? After all, your system is admittedly a cobbled together one at that.

  6. Joel says:

    It is lightning season, and it wouldn’t be the first time a surge killed a digital display. But I’m not aware of any recent close strikes.

  7. bmq215 says:

    I’d say pop it open and take a look. If the thermal fuse melted you should be able to tell by looking and definitely with a multimeter. They’re supposed to go at 200F or 15A, but obviously that’s the kind of thing that you want to design conservatively and the cheap wax-based ones can break down with age. Otherwise it’s probably a dead capacitor which are super cheap to replace but probably fiddlier than you want to get into (the thermal fuse may be too, for that matter).

    Might also be a broken wire, also easy to diagnose and fix.

    There’s nothing inside that’s dangerous when it’s unplugged, although I’d be a little careful with the 1uF capacitor (the big green rectangle next to the 120V socket).

  8. Robert says:

    You owe DeForest Kelly some royalty fee. Funny. Good luck with the KAW.

To the stake with the heretic!