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Forum Index : Electronics : 12V signal input, 40A WiFi relay to be switched remotely - Help
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| domwild Guru  Joined: 16/12/2005 Location: AustraliaPosts: 873 |
My Fronius inverter will give me a 12V output when solar production reaches a certain kW level and I can program the Fronius to switch on a H/W element for a certain time on/off for a total of x hours stopping at y hours in the evening. At the H/W system a 40A Wifi relay is envisaged, but here I am getting stuck as that relay can be spoken to via eWlink via a smartphone or PC app, but not if a 12V output is happening remotely. Is there a 433MHz solution possible to drive a 40A relay remotely for a 2450W heating element from a 12V signal at the other end of the house, probably 25 meters away? Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| mab1 Senior Member  Joined: 10/02/2015 Location: United KingdomPosts: 149 |
I can't help with wireless solutions, sorry, but if it were me I'd look at running a small wire:- bell wire or telephone wire from the Fronius to a solid state relay at the other end of the house. 40a ssr ebay Keep it simple is my way. |
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| flyingfishfinger Senior Member Joined: 12/09/2020 Location: United StatesPosts: 102 |
There's a variety of things that will get you what you want, if you're willing to do a bit of soldering / simple circuitry. For example, these types of things come in several variations, hack the keychain side of it. R Edited 2021-05-24 06:16 by flyingfishfinger |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Thanks for suggestions. The Fronius inverter talks to the Internet and production figures are available in realtime, so I am wondering if Linux could be useful here with a feature called wget to read the production off the web. Then it may be possible to activate eWelink to send a WiFi signal to the relay to switch on if the production is right. My Fronius installer is not able to install the simplest solution, namely connecting a relay in the switch board directly to the Fronius with its 12V signal at the other side of the single brick wall. How difficult is it to hack one of these keychains, in other words a 12V signal is to close the ON switch and a drop in 12V does the OFF switch? Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| flyingfishfinger Senior Member Joined: 12/09/2020 Location: United StatesPosts: 102 |
Depends on whether or not you're comfortable with a soldering iron. What is the exact output signal from the device? Is it a 12V signal turning on, and staying on until the relay needs to turn off, or something else like a pulse on / pulse off? I'm assuming you have power at the location of your relay, otherwise you couldn't run the heater thingie. You'd also need something like this or similar to control the remote side. In the simplest form, you'd keep the coin cell in the remote, trigger the button with the above board and attach your load to the receiver end. You'll need a 12V supply on the receiver end to power it, but that's also easy to get. Given all these parts for ~$20-$30, you could do this in a couple hours. Or, if you want to spend more there might be a less DIY solution. R Edited 2021-05-27 02:55 by flyingfishfinger |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Thanks flyingfishfinger. When I was young I believed all fish come shaped like a rectangle! Reading the Fronius manual I found that 12VDC stays on and after a user-defined time period switches off. Normally it is driving the coil on the H/W relay directly. I prefer to stick with WiFi, but those remotes available for 433MHz solutions also come with WiFi set ups. A further complication arises with remotes as one press switches ON and a second button's press switches OFF. The Fronius expertise is not available in Perth to install the relay directly, so I am in the unenviable position to tell installers the Fronius has been installed and now I want a relay installed. I forgot to blackmail the initial installers they get the job but only if a relay gets installed at the same time. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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