Looking for USB mains power monitor

alanwsg

Does anyone know of a source for a USB mains power monitor?

What I want is something like one those "OWL" power monitors or alternatively one of the plug-in types that measure a single appliance, but I need it to log the data regularly and then allow me to download it to my pc as a spreadsheet or similar.

It'd need battery backup to record through power cuts as well.

kwikbreaks

My son has one of these...
http://www.electricity-monitor.com/efergy-usb-wireless-energy-monitor-p-85.html which allows him to download data (as a CSV I think)

I have the older version with no USB and it has been very reliable.

All the system wide models I'm a aware of are battery only for the transmitter so when that goes flat you'll lose some data. None are accurate enough to check the meter.

I'm intrigued to know what you expect to record when there is a power cut - all the units I'm aware of run off batteries or adaptors anyway but sod's law dictates that if you get a cut the battery will be flat anyway.

penrhyn

Efergy e2 USB Wireless Energy Monitor

Google is your friend.

alanwsg

kwikbreaks wrote: »

I'm intrigued to know what you expect to record when there is a power cut - all the units I'm aware of run off batteries or adaptors anyway but sod's law dictates that if you get a cut the battery will be flat anyway.

I expect to record that there's been a power cut, when it started and when it ended!

The Efergy thing isn't really what I wanted, and some of the reviews are less than flattering!
I wanted something more akin to a data logger, I don't really want to mess around with a wireless connection and batteries that'll go flat just when you need them. I want something that I can plug in, that'll record the supply parameters quite frequently (e.g. once a minute) and then let me download the data in a form suitable for loading into a spread sheet.

pothole50

I recently purchased the Efergy usb monitor, Maplins £29.99 I already have the Owl but wanted one I could plug into my computer and log the hourly data, if you do have a power cut the data will record zero. One of the reasons I bought mine was I had a new meter fitted, my old mechanical economy 7 meter was faulty, but within 3 days the main ceramic fuse blew first time ever in 30 years.
I had the power supply off for over 6 hours, waiting for one guy to come and tell me its not the meter, pulling out the old ceramic fuse, and telling me because its has asbestos surrounding the fuse wire he is not allowed to change it, so waited for the EON guy who just changed the wire!!!!.

I have three wires coming from the meter, one to main fuse box, one to emersion heater one to shower, so I had the owl connected to these, but not to the garage supply which fed the pond pump and filter.
The instructions for the owl and Efergy say to fit it between the meter and fuse box but now I am very wary now about blowing the main power supply ceramic fuse to my home.
So what I did was connect the owl and efergy between the ceramic fuse and meter, I could now see the wattage being loaded on the fuse. Surprisingly when I did this on the old meter (which I always thought was giving high reading, when fitted about 10 years ago as my bills seemed to go up) the owl always read 100w, even with all the power switch off, so has my meter been pulling 100w a day for 10 years and charging me for it we shall never know.
The new meter fitted and the Efergy and Owl between the ceramic fuse and meter when the power is off both monitors read zero.

How has my Efergy paid for itself, as an experiment as you do with new gadgets I switched the power on different supplies, the biggest shock was when I switched on the supply to the garage which fed the pond pump and filter that was pulling 230w, not much but times 24 then 365 it was costing £180 a year, so now it switches on at night for 7 hours cheap rate.
Between the 2 monitors the Efergy is the more accurate and sensitive, when everything was off the Owl read zero the Efergy read 0.009W, on investigation the OH hair-dryer was off but plugged in and switched on at the wall, even energy monitors you plug into the socket pull 0.014.
Well that's my experience I love the Efergy just plug into the computer each day and read off your usage for the day, see the highs and peaks of usage, not sure if the Efergy is what you are looking for but if the powers off it reads zero, as I checked it today between 10-11pm because I was curious. It cant tell me when it went off and came on again just that there was no supply between 10-11. But if you are at home you would know the times, and if you were not, with a history of data built up over a few weeks you should be able to pinpoint it more accurately, if you always use 200w between 3am and 4 and the next day its 100w then you know you had an appox 30min power cut, coupled this with a mechanical electric clock, (not one of those digital things that just flash when they come on), that will tell you the time the power was off for, so its now 10am your clocks reading 9:35am, you had a 35min power cut between 3-4am.

Probably not what you were looking for but someone's experience is always useful to somebody.

pothole

kwikbreaks

If you don't have electric storage heaters you need to look very carefully at your "economy" 7 tariff. Typically these involve a higher standing charge (or the high rate first few hundred units equivalent) plus the standard rate is substantially higher than for a single rate tariff.

Unless you are using quite a lot of electricity in the cheaper rate period you'd be better off (by a lot in my case when I did the calculations) on a single rate tariff. It takes about a month for the electricity company to change the meter but there is no charge for doing it.

It could be that you can make a bigger electricity cost saving with a £1 calculator than any energy monitor....

pothole50

Looking carefully at my E7 and considering the history from British Gas, at the moment on their Websaver 5 Tariff 9.04p day 4.03p night doing all right with the usage, fiqures thrown into a speadsheet not making an enormous saving with E7 against normal single tier, but enough to justify it. Will have to way up the pro's and cons after Feb when Websaver 5 comes to an end.