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Forum Index : Electronics : Daily Kwh usage meter wanted
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| MickWh Newbie  Joined: 08/05/2010 Location: Posts: 19 |
Hey guys, I am in a off-grid solar powered house. The regulator that I use for the solar panels has a Kwh meter to show how much the panels have generated so far today, also has info with regards to instant amps/watts going to the battery bank. What I would really like is a meter on the usage side showing the same kinda of display. How much power has the house used so far today? Can I put another load of washing on or whatever. I imagine it would need to have a reset button to restart the meter. I was wondering if the classic picaxe chip might be the perfect backbone for the circuit? something like Gizmo's windmill controller slightly modified?? Many thanks, Michael. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Michael The Piclog could be used to do that, but the Piclog needs a PC to record and process the data. Do you have a house PC thats running all the time? A easier option might be to plug a power usage meter into the output of your inverter. Most electronics places sell them. This is the same as the one I bought from Jaycar 
http://www.jaycar.com.au/productView.asp?ID=MS6115 Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Glenn, Why do Jaycar try to install cookies to my pc now you have posted this link? That is without opening the link just opening this thread. Pete. Sometimes it just works |
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| MickWh Newbie Joined: 08/05/2010 Location: Posts: 19 |
I have one of those jaycar style meters and it is great, but was thinking it might be a bit on the "dodgy" side to rewire the powerbox to run the whole house through basically an extension cord that plugs into the power meter. Just had the idea of taking the unit apart to see if that might be an option. I do have a laptop that runs a bit, but certainly not all day. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
No idea Pete, it would just be some kind of analytics cookie or product popularity cookie. Just about every web site uses cookies these days, including this one. A cookie on a product would be used to see if there is any ongoing interest in that product. By having a cookie, it means they would know that someone has looked at the product more than once. Cookies are really so harmless its ridiculous. They can not be used to identify you, your OS, you country, anything. All they do is store a snippet of their info on your PC. For example, the cookie from this forum simply tells the server that user such and such has been here before and they want to be automatically logged in please. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Far from a fact. They may be harmless in and of themselves, but they can most certainly store information and more importantly, be coerced to reveal that information to people and in circumstances you may not be aware of or appreciate. Generally however, they are as you say benign. But then, generally kitchen knives don't kill people either. |
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readyakira Senior Member  Joined: 17/07/2008 Location: United StatesPosts: 114 |
I think what downwind was saying is he didn't go to jaycars site. This site tried to put a jaycar cookie on his comp. It is probably embedded in the pic Pete. Like when you open an email and it says some pics were blocked. They use cookies in pics to monitor where they are, who sees em, and how often. Don't you think Free/Renewable energy should be mandatory in new buildings? |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Cookies are not "embedded in" images. The image of the power-meter from jaycar is in fact a LINK TO the jaycar site: http://www.jaycar.com.au/products_uploaded/productLarge_9554 .jpg If the image were downloaded and sent to the forum as an image in its own right, this wouldn't have been an issue, but there are then copyright and similar issues. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I dont really care, i just hate things trying to shove cookies onto my pc. You dont realize to the extent this happens until you turn off excepting cookies. I find very little difference in viewing sites when i refuse their cookies, but you get harassed by them trying to get you to except cookies. I think of my computers well being, and too many cookies will make it fat and slow 
Or you might say its like a dog marking its teritorry in cyber space. Pete. Sometimes it just works |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
1. I didn't put the image there. 2. I didn't try to shove the cookies up your pc 3. As someone who lives internet security for a job, I'm absolutely cognisant of the extent and impact. A properly constructed site shouldn't be affected at all (for this type of use) |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Ross, My comments were not directed at you, and was only a my view of every site wanting me to except cookies regardless of if i want them or not. Pete. Sometimes it just works |
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| Robb Senior Member Joined: 01/08/2007 Location: AustraliaPosts: 221 |
I don't know what browser you have but on firefox you can set it to clear all cookies each time you exit the program. Its a good way to make sure you remember your password  Alternativly just hit ctrl shift delete and clear what you want any time. |
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Phil73 Newbie Joined: 22/07/2010 Location: AustraliaPosts: 2 |
Hi Michael, We have an efergy energy meter. A transmitter sits in our meterbox which has a cord and a clip thing that you clip around the mains cables. A small lcd display in the house shows our current, and past history energy use. Not sure if this is what you were after or something more advanced. Ours does seem to work quite well we have had it about 12months. Just google efergy energy meter, I got ours off ebay. Phil. |
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Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Michael, Putting the lid on the cookie jar for the moment, you don't indicate whether your house runs on 240V AC (ie through an inverter), or on DC. Presuming it is AC, then very inexpensive supply authority type kilowatt hour meters are available out of China, and you should have a look at the offerings on Alibaba.com. These are not the clip on kind, and you have to read them directly (rather than the remotely read efergy unit described as in the previous post), but they are affordable. If your house runs on DC, then it becomes a lot more complicated, although the measurement is actually much simpler. Its just that there is no big demand for DC kwh meters. Regards Don B |
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| MickWh Newbie Joined: 08/05/2010 Location: Posts: 19 |
Thanks Don, wow a lot of options at Alibaba.com, house runs on AC. Don't mind the non clip in version of meters, I guess my main problem is the "resetablity" of the meter. I seen the wired in versions before but my impression is that they are more aimed to measure the usage of a week or month of rental property. This tends to lead them to have less specific detail of a daily "so far" use. Thanks, will keep scrolling. |
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Loomberah Regular Member  Joined: 11/06/2008 Location: AustraliaPosts: 43 |
I use one of these, which works very well. RPC kWh meter It displays to 0.01kWh, I log it each morning along with my charging controller etc, and can easily keep track of daily usage on a spreadsheet. Loomberah weather +solar&UV, astronomy, photography, organic farm |
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ledsales Newbie Joined: 09/08/2010 Location: AustraliaPosts: 1 |
There's a heap of options for energy meters, including the powermates from shop.ata.org.au and the din rail mount kWh meters like the one listed above, but you can get them a lot cheaper if you look around (try ebay). The Jaycar meters are crap, hate to say, we tried them out and they were hopelessly inaccurate to the tune of several hundred % on some loads. They don't handle loads with poor power factor well at all, and the PF listed by the meter is often way out as well. There's plenty of clip-on meters as well, try www.smartnow.com.au for some interesting units, but there's many others. Just remember that the clip-on meters only measure current, they can't differentiate between real and reactive power (to do that you need real time voltage and current measuring and integration), so they display higher than correct readings for any device with a PF less than 1. If you don't know what power factor is, google it... |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I find the effergy is a better small cost effective unit that has enough to satisfy me as a daily read device. Its voltage is adjustable 220/230/240/250 etc this means you can set it up to be pretty accurate, my local grid is 250V+ most of the time but the SMARTNOW ENVI unit i have doesnt have an adjustable Voltage thus is set at 230V, this makes its figures seriously distorted. It does however have a saving grace and that is PC connectivity and it works with google powermeter (which currently doesnt support both generation and production) and other software allows you to correct the errors (whats being read on its screen is still in error). Then there is a TREC which I found quite useless as it logs nothing. Karl Luck favours the well prepared |
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