<![CDATA[Relay options for higher power?]]>I would like to set up a small system with the following components:

  • moisture sensor(s)
  • temperature sensor(s)
  • relay switching of mains power up to 110V / 1200W

The power relay is what gives me the problem.
Any suggestions ?

The applications at my house are multiple:

  1. Control of attic fans. The off-the shelf controller on the attic fans just turn them on when the attic temperature is over 80 degrees F, but I want to not turn them on unless the attic is hotter than the outside. So I want a 10-foot cable to a sensor that can be under the eaves.
  2. My wife's palm propagation greenhouse.
  • thermostat control of heating mats under the germination flats
  • thermostat control of fans, again need to ensure that the outside is cooler than the greenhouse before turning it on
  • warning when plants are getting dry

But a 60W power limit is too little. Is there a good, safe mains power relay that I can drive with a contact closure in the Onion's relay module?

I doubt that I am the only one with these needs.

]]>http://community.onion.io/topic/3142/relay-options-for-higher-powerRSS for NodeTue, 17 Mar 2026 06:14:45 GMTThu, 13 Sep 2018 19:28:44 GMT60<![CDATA[Reply to Relay options for higher power? on Thu, 13 Sep 2018 19:28:44 GMT]]>I would like to set up a small system with the following components:

  • moisture sensor(s)
  • temperature sensor(s)
  • relay switching of mains power up to 110V / 1200W

The power relay is what gives me the problem.
Any suggestions ?

The applications at my house are multiple:

  1. Control of attic fans. The off-the shelf controller on the attic fans just turn them on when the attic temperature is over 80 degrees F, but I want to not turn them on unless the attic is hotter than the outside. So I want a 10-foot cable to a sensor that can be under the eaves.
  2. My wife's palm propagation greenhouse.
  • thermostat control of heating mats under the germination flats
  • thermostat control of fans, again need to ensure that the outside is cooler than the greenhouse before turning it on
  • warning when plants are getting dry

But a 60W power limit is too little. Is there a good, safe mains power relay that I can drive with a contact closure in the Onion's relay module?

I doubt that I am the only one with these needs.

]]>http://community.onion.io/post/17675http://community.onion.io/post/17675Thu, 13 Sep 2018 19:28:44 GMT<![CDATA[Reply to Relay options for higher power? on Fri, 14 Sep 2018 02:30:03 GMT]]>Regarding the relays, maybe think about SSR (solid state relays). They're a bit more expensive but controllable with logic signals and available up to very high current - beyond 100A at mains voltages.

The AC one also generally offer zero crossing switching i.e. switch at the 0V portion of the AC cycle.

HTH.

]]>http://community.onion.io/post/17681http://community.onion.io/post/17681Fri, 14 Sep 2018 02:30:03 GMT