Watt Meter / Kill-A-Watt alternative - Page 1
Forum section: electronics / testgear

author: arcfault
author_rank: Contributor
timestamp: December 23, 2023, 05:17:39 pm
content: Hi everyone,I like to be able to measure appliance power usage easily. Extreme accuracy is not important. I've owned three Kill-A-Watts in the past few years, but two have died. Not even used a lot. The one I opened up had a blown fuse and looked sketchy as far as the soldering goes. Another one had burn marks on the plastic.It seems like there's some very high end equipment options. I'd like something similar, but of actually good quality (and maybe UL listed?)I'm in the US and only need to do 120VAC single phase stuff.Would appreciate any suggestions you can offer.Thank you!

author: coppice
author_rank: Super Contributor
timestamp: December 23, 2023, 05:27:22 pm
content: If you think a genuine Kill-A-Watt is bad, you'll hate most of the alternatives. Some of these don't even measure active power. They use some crude RMS voltage and RMS current measurements, then multiply the answers. So, the are calculating apparent power, and not the active power most if us are interested in. Many have terrible dynamic range. Its an easy product to make with a 20 cents utility energy measurement chip, but it still something most people make a horrible mess of. Some of them do have a really attractive case, though.

author: arcfault
author_rank: Contributor
timestamp: December 23, 2023, 06:14:10 pm
content: I'm not 100% certain they have all been genuine, but I think one was bought new from Amazon and maybe another new in packaging, so I would be surprised.I'm completely fine with the unit other than the reliability. Not sure if it's worth replacing the fuse or not, if it'll go out again. It's just that 2 out of 3 dead, with such limited usage, is really disappointing.

author: coppice
author_rank: Super Contributor
timestamp: December 23, 2023, 06:17:53 pm
content: Was the failed fuse a small value one for the electronics, or a big one between the input and output? If its a big one maybe someone just blew the fuse with an excessive load, and it just needs replacing.

author: bdunham7
author_rank: Super Contributor
timestamp: December 23, 2023, 07:10:53 pm
content: I have an old one, model P4400.01, that has worked fine for many years. It is pretty accurate and I'm not aware of anything similar that is better. I don't use it on space heaters or large electric motors though, since the 15A maximum rating is a "blows up at" spec, not a safe level for continuous operation. I don't know if newer versions are worse. If you have blown F2--the 15A fuse set way off the board--you have simply overloaded it. Keep in mind that many large appliances may have surge loads much greater than 15A, although anything designed for continuous usage, like a space heater, should be limited to 12A continuous draw.

author: HKJ
author_rank: Super Contributor
timestamp: December 23, 2023, 07:44:29 pm
content: There is a couple of Chinese power meters that is good. Today it is not difficult to make a good power meter, you get most of it in a single chip. Some brands adds a lot of extras to the basic measurements from the chip, one of the more advanced have looked at is called PR10https://lygte-info.dk/review/Power%20Zhurui%20Power%20Recorder%20PR10%20UK.html. One of the issue with the advanced meters is that they use a few watts (Up to 2.2W for the PR10) in addition to the load.

author: J-R
author_rank: Super Contributor
timestamp: December 23, 2023, 11:11:27 pm
content: I have four older Kill-A-Watts, zero failures. I could imagine the quality dropping off as they race to the bottom, though. Simplest option is just keep replacing them...I also have the Amprobe ELS2A. What you can do with it depends somewhat on your clamp meter's features, but this (or a similar product) could be a reasonable replacement for not much more money.Another product I have that is no longer manufactured is the Extech 380803. You may need to be patient in order to get one at a reasonable price. It's a bit clunky to use and chunky to haul around. I really only use it when I need high accuracy.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 23, 2023, 11:25:50 pm
content: For stationary household units, have tried these.the white ones are 3 different versions, and the blue ones are the same, just different revisions where they updated the screen, check HKJ link for a review.--Different pictures of the different interface templates & settings, wifi, Bluetooth, apps, temperature and pollution metrics, annual timers etchttps://tinyurl.com/2ub7ypwx

author: Veteran68
author_rank: Frequent Contributor
timestamp: December 23, 2023, 11:51:25 pm
content: I have a Kill-a-Watt but have always been interested in the Hopi power meter that Big Clive uses. This thread reminded me to put one in my AliExpress cart for my next order.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 24, 2023, 12:28:55 am
content: The consumer grade stuff is where I would look, I've only got one and it's seen low use by my Kill-A-Watt has been good so far, but if you want to splurge, something like a Hioki 3332 would be a couple steps up, and they seem to be a little under $400 on ebay used.

author: Gyro
author_rank: Super Contributor
timestamp: December 24, 2023, 11:12:16 am
content: Quote from: Veteran68 on December 23, 2023, 11:51:25 pmThe HOPI (HP-9800, to give it its searchable name) needs a little work to make it safe but has decent accuracy. Here's a teardown/improvement that I did recently. Notice that the recent versions don't have the tiny little internal mains fuse...https://www.eevblog.com/forum/testgear/hopi-hp-9800-power-meter-(recent)-differences-and-safety-improvements/