Shelly Setup for Dual HWCs

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ashtonaut

614 posts

Ultimate Geek

#317877 22-Nov-2024 23:59

I run Home Assistant at home, and want to properly integrate my hot water heating, ideally also with HWC energy monitoring.

I have two electric hot water cylinders, one 3kW, and one 2kW. Each is on its own 16A breaker. I want to have independent control of each unit through HA so I can set custom heating schedules, boost when I need it, etc, and know how much power they are using.

I’d like to mount the gear on the DIN rails in my switchboard (by electrician).

What hardware is recommended here?

A Shelly Pro 4 PM looks like it can handle the switching without needing a contactor, and it will also give me power monitoring of the loads, plus an extra 2 channels for ‘other stuff’ later on. Potentially an issue that it recommends only 10A per channel even though it’s rated for 16A.
https://www.lykalyte.co.nz/products/shelly-pro-4pm

I assume an alternative of 2 x Shelly Pro PM would also do the trick. These appear to be able to do 16A each no issues.
https://www.lykalyte.co.nz/products/shelly-pro-1pm

Or another alternative, the Shelly Pro 2PM?
https://www.smarthome.com.au/product/shelly-pro-2pm-double-relay/

Can someone please confirm (or not) that I’m thinking along the correct lines here? Am I fine without using a separate contactor, particularly for the larger load?

chimera

506 posts

Ultimate Geek

#3312254 23-Nov-2024 20:42

Just had my sparky install this on Friday (amongst other clean up) to do exactly the same thing, control HWC power and read wattage.

https://a.aliexpress.com/_mqE3DHt

Bought the 40A breakers

ashtonaut

614 posts

Ultimate Geek

#3312255 23-Nov-2024 20:57

Your sparky was OK installing kit from Aliexpress? I’m the first to purchase stuff from there but I get nervous with 240V kit…

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#3312256 23-Nov-2024 20:57

Rip that out; sparky should probably have refused to install it.

chimera

506 posts

Ultimate Geek

#3312262 23-Nov-2024 22:09

I was waiting for the highly generic “it’s from China, rip it out” statement

If you’re that concerned go buy the EXACT same product from Dick Smith NZ

https://www.dicksmith.co.nz/dn/buy/oakwoodhousedecor-tuya-wifi-intelligent-circuit-breaker-wireless-remotes-control-switch-mobilephone-app-remotes-viewing-is32319-5-889-1450242321

lxsw20

3552 posts

Uber Geek

Subscriber

#3312266 23-Nov-2024 22:42

"This product is sold by a third-party seller and they are responsible for their product, the content of their listing and any exchanges of return of their product."

It's actually not sold by Dick Smith, its a 3rd party. Bet you any money its not certified to be used in NZ.

It's your house/family at the end of the day, if you're happy with it, so be it.

chimera

506 posts

Ultimate Geek

#3312267 23-Nov-2024 22:53

I’m happy with it

Had plenty of Chinese home automation products in past 15 years that haven’t caused me any issues

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#3312271 24-Nov-2024 06:01

Only has to happen once.

Quic Broadband

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ashtonaut

614 posts

Ultimate Geek

#3312272 24-Nov-2024 06:07

I’ve got no interest in arguing about whether what you got is safe or not 😀

However, it looks like it’s a Zigbee product, I’m looking for a solution that is either direct wifi or ethernet, hence the Shelly products.

I guess I could always purchase the Pro 2 PM, monitor temps carefully, and if I’m not happy, get it changed to drive an external contractor for one or both of the HWCs, and accept if I do that I lose power monitoring.

Does anyone have a recommendation for a contractor that can be driven by a Shelly relay, does 16A, and has a physical on/off/auto switch?

chimera

506 posts

Ultimate Geek

#3312632 25-Nov-2024 10:51

Just followed up with sparky about the Aliexpress breaker, he said there is another RCD / MCB used that then feeds to the aliexpress one.

I think that means it must be...

POWER --> RCD --> MCB --> TONGOU --> HWC

chimera

506 posts

Ultimate Geek

#3312797 25-Nov-2024 17:15

ashtonaut:
However, it looks like it’s a Zigbee product, I’m looking for a solution that is either direct wifi or ethernet, hence the Shelly products.

They do both WiFi or Zigbee

It may not be your level of risk appetite, but wiring like I've mentioned above may provide a bit more peace of mind

ashtonaut

614 posts

Ultimate Geek

#3321758 17-Dec-2024 22:15

Just to close this out, I ended up getting a Shelly Pro 4 PM in their Black Friday sale ($161NZD including shipping). Shelly provided me with Aussie compliance documentation, and my sparky installed it. Only using 2 channels for now with one HWC on each channel. Took all of 5 minutes to update firmware and get it into HA, then another 5 mins to get some timer automations set up for overnight water heating. Very pleased with the device. Having physical control from within the switchboard with a small LCD display is an added bonus.