Control Spa from Home Assistant to Maximise Excess Solar Power

Forums › Gadgets, robotics, home automation, electronics (including wearables) › Control Spa from Home Assistant to Maximise Excess Solar Power

sfrasernz

227 posts

Master Geek

#303555 18-Feb-2023 12:24

Has anyone successfully got HA talking to their Spa?

I have a Caldera Capitolo which I want to manipulate the set temp depending on our excess solar power production.

I'm still awaiting a response on the availability of a wifi module for this spa but if available I'm not confident it'll easily integrate with HA.

There's a useful project here for Balboa boards using RS485 but I'm not sure if it would apply to this board. I have posted there as well.

I did consider a Tasmota power switch relay but the spa uses an RCD which trips each time it loses power and requires a manual reset so I'd never be able to get it to turn back on remotely.

Does anyone have any clever ideas to acheive my goal of managing the spa from HA?

Heres a photo of the board:

From my research this board is also used in Hot Spot spas under the Hawk brand and in Hot Spring Spas under the Eagle brand.

I've also found a Watkins RS485 module so it could indeed be using the RS485 protocol. Just need to figure out how I can tell...

eonsim

398 posts

Ultimate Geek

Trusted

#3038577 18-Feb-2023 13:01

I've got a older style spa where the temperature can't directly be controlled except by a knob on the side. I have managed to get the Spa set up and controlled using HA and a Shelly 1.

I simply set the manual temperature control to the highest level I thought was safe (around 40.5C), then I had the Shelly PM wired into the timer circuit (the spa came with an analog timer) inside the water proof housing the timer was using and then used the sensor addon for the Shelly to add a water proof sensor to the spa. The shelly is used to turn the spa on an off dependent on the solar power and simply turn the spa off when it reaches a bit off the target temperature. It's not perfect as when you use the spa and set it to run with out heating you need to remember to switch it back to auto, but it does work. HA has a target temperature and solar boost temperature for the spa (0.5-1C higher), if there is plenty of spare solar we heat the spa upto the solar boost temperature during the day, and then the temperature naturally drops back down to close to the target temperature by the time we want to use it late in the evening.

sfrasernz

227 posts

Master Geek

#3038578 18-Feb-2023 13:07

Thanks that gievs me another option. I'm going to check with my Sparky but I think I should be able to remove the ELCB (not an RCD as I said) from the spa cord because there is an RCD on a the distribution board.

By doing that I could run a Shelly1 or Tasmota and control through HA as you do. As you say not perfect but achieves the goal of maximising the solar energy.

Chippo

129 posts

Master Geek

Trusted

#3038588 18-Feb-2023 14:07

As an alternative you could switch power companies to Octopus. I spent 2 years maximising solar generation just for them to flip export tariffs upside down.

When it's 17c export and 13c import overnight - suddenly I don't want anything using my solar during the day at all 😅

I work for a global Data Protection Software company - But my opinions are my own.

eonsim

398 posts

Ultimate Geek

Trusted

#3038597 18-Feb-2023 14:43

sfrasernz:

Thanks that gievs me another option. I'm going to check with my Sparky but I think I should be able to remove the ELCB (not an RCD as I said) from the spa cord because there is an RCD on a the distribution board.

By doing that I could run a Shelly1 or Tasmota and control through HA as you do. As you say not perfect but achieves the goal of maximising the solar energy.

The one thing I'd note is my set up doesn't have the Shelly in the load circuit for the heater/pump it has it on the switch circuit. That means the max load on the shelly is only ever about 1W as it's just controlling the switching. If you have the Shelly in line to the full power circuit the spike when you turn the pump on and off may kill the shelly as even rated for 16AMP, having a load close to that plus the surge can really heat them up (and if they're sitting inside the spa cover they'll already be pretty warm). If you want to put them in the load path I'd suggest you get an electrician to install a suitable rated contactor and then have the shelly control the contactor, that will mean the full load doesn't got through the shelly and it's much more likely to survive.