Solar, HWC, Shelly… Oh my!

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#3370324 4-May-2025 10:09

Whats everyones experience with contactor noise? I'm looking to get sparky to install shelly with contactor, but switchboard is central within house so noise is a concern. Ok with the on/off clicks, but if it hums while on thats a no go. I've seen places in AU recommend Voltex HumFree contactors, anyone used that?

MadEngineer

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#3370331 4-May-2025 11:05

Mine doesn't hum. Our switchboard is in the garage and in an adjacent room a soft thud noise can be heard when it changes state. From elsewhere in the house if I listen for it when changing its state I can hear it but otherwise don't notice it. This is in a house with wooden laminate flooring where sound travels easily.

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#3370332 4-May-2025 11:13

prob:

I use a Schneider / PDL Iconic style timer set to turn on the hot water over the sunny part of the day, 11 am to 1 pm with a boost in the early morning 3 to 5 am. I found that without the early morning boost the showers sometimes weren't hot enough.

What is your experience, is the water hot enough in the morning?

As an aside, these timers can be converted to run Zigbee (currently Bluetooth and hard to access via Home Assistant) so I plan to manage hot water via Zigbee and play with triggering hot water while there is excess power in near future.

Bluetooth Hot Water Cylinder Control Kit

I originally set it to simply turn on at a duration after sunrise and off at a duration before sunset. After gaining better knowledge of it's readings I have changed this to be triggered off the CT load which picks up the solar generation. This seems to be keeping the water hot enough so far.

You could add a condition like below where only once the generation has dropped below a certain level AND it has been on for three hours does it then turn off. Ours is still under ripple control which I kinda want to keep.

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timmmay

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#3370356 4-May-2025 13:43

Nate001:

Whats everyones experience with contactor noise? I'm looking to get sparky to install shelly with contactor, but switchboard is central within house so noise is a concern. Ok with the on/off clicks, but if it hums while on thats a no go. I've seen places in AU recommend Voltex HumFree contactors, anyone used that?

I have never heard a hum, but I've never stood close to the switchboard to listen. The on of click is more of a solid clunk that can be heard for quite a distance even through doors or walls, if you have a light sleeper it could potentially disturb them.

MadEngineer

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#3378200 29-May-2025 22:34

Next up, using chatgpt to produce python code to pull data ...

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rjbathgate

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#3396180 22-Jul-2025 14:20

Sorry to gatecrash this thread, but we have just installed Solar and Battery (Sigenery) and are now looking at hooking up our HWC to a Smart Relay, with the basic end goal of setting up a basic on/off timer via Home Assistant, for example:

Turn off hot water at 5pm when the sun generally goes down
Turn it back on at 10am when the sun is generally up.

It won't eliminate grid use for HWC but will hugely reduce it (hopefully).

I've seen people recommend and use the Shelly Plus 1 or Shell Plus 1PM - a unit that is retrofitted inline to the HWC supply rather than a rail in the switchboard.

These units are rated to 16A and our HWC is 3kW, so the maths says it'll suffice, but the docs for the device read:

Up To 3500W
With a Shelly Plus 1PM you can control wide range of devices and appliances. (Only recommended for short durations at higher loads).

As I am not really sure where the line of 'short durations at higher loads' is, has anyone any experience using one of these 16A devices on a HWC?

This Shelly Plus 1PM unit is dirt cheap ($40) as opposed to something like the Shelly Pro EM-50 + contactor.

There is also a rail-based Shelly Pro 1, but this is also only 16A.

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timmmay

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#3396186 22-Jul-2025 14:54

I've done that and it's working well. I saw multiple people say their Shelly devices burned out when you put the full current through it, I suggest using a contactor. I think I posted a link to what I used somewhere on this thread, if it's not on this thread it will be somewhere around here and I could find it later. You're welcome to send me a message if you can't find it.

I have solar with the same inverter, home assistant, I could help with dashboards and automations and such that are working for me.

rjbathgate

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#3396188 22-Jul-2025 15:15

timmmay:

I've done that and it's working well. I saw multiple people say their Shelly devices burned out when you put the full current through it, I suggest using a contactor. I think I posted a link to what I used somewhere on this thread, if it's not on this thread it will be somewhere around here and I could find it later. You're welcome to send me a message if you can't find it.

I have solar with the same inverter, home assistant, I could help with dashboards and automations and such that are working for me.

Awesome thanks. Yeah it looks like you used the EM50 plus a contactor, which definitely looks the more sensible option vs something that might burn out over time.

I've just got the Sigenergy set up in HA (took a while to figure out which sensors are the key ones, as there are a lot in there!). My automation plan was going to be pretty basic (at least to start with) - and entirely time-based (turn on HWC during daylight hours, turn it off when it's dark!).

I would like a nice dashboard view for my Sig set up - haven't got around to that yet (as to be fair, the Sigenergy app is pretty good for displaying metrics)

I've done similar with our Heat Pump - pre-heat the house before the sun goes down.

MikeFly

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#3396216 22-Jul-2025 16:48

Shelly have these as well https://www.shelly.com/products/ogemray-25a-smart-relay

timmmay

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#3396218 22-Jul-2025 17:10

I have automations that turn the hot water cylinder on when there's enough power available, but it also considers the weather. On a cloudy day the threshold is lower, on a sunny day it waits for full power to be available. There's also a basic timer that always turns on at a specific time, and it turns off something like an hour before sunset or when it's had 4h heating time per day. Or something like that. I set that up before we had the export meter installed which took a couple of months, these days I probably wouldn't bother, I'd just use a basic timer.

Does that Shelly Smart Relay have a contactor inside it? If not I'd skip it and go for a proper high current contactor to avoid risk of burnout.

MikeFly

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#3396219 22-Jul-2025 17:13

Yep. It also has huge terminals, 5mm.

"Smart relay powered by Shelly, designed for precise control of large appliances up to 25A / 6000W. "

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MadEngineer

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#3397349 26-Jul-2025 20:47

Anyone have any thoughts on this?

Solar page:

Genesis Energy:

Not sure how I can be using 1.11kWh at 11am when I started exporting more than I was using at 9.15am. Hot water cylinder using ~3.6kW from around 9.15am through to around 1pm.

Oddly, they arbitrarily changed my plan from one that had a daily charge of 80cents/day to 120cents/day with the new meter.

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MadEngineer

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#3397353 26-Jul-2025 21:15

Based on that, it looks like they've got the solar connected to the Anytime side of the meter, then when the hotwater is pulling power via the Controlled side, I'm only being offset by the monetary value of the solar export.

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MadEngineer

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#3398064 29-Jul-2025 15:55

So, after a 2hour chat, Genesis tells me I need to get an electrician to rewire the meter. Yeah work that one out.

Shockingly the hot water is always going to be billed at the controlled rate regardless of Solar generated. If you’re getting a new meter, the new meter will be replaced with one that does controlled rates - that’s set by Powerco according to Genesis

have put this to the disputes tribunal.

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MikeFly

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#3398068 29-Jul-2025 16:07

Sounds a bit like 3 phase if you generate on only one, you get billed for the other two even if your total generation exceeds the total of the three phases.

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