Hot water tank sensor to monitor EDDI

Picaresque

Hi,

I have an EDDI to heat my water from the PVs with still the original Sink / Bath switch in the hot press.
However, I have no indication of the actual temperature inside the tank.

I would like to be able to monitor the temperature of the tank so I don't have to boost the Eddi or heat the water with my boiler.

Ideally, I would like to connect it to Google Home Assistant.

I have found this one https://www.domadoo.fr/en/devices/5998-owon-zigbee-connected-outdoor-temperature-sensor-with-probe.html, but not sure if someone has used another one.

Any recommendation?

Thanks

Picaresque

In the meantime. I found this calculator, which seems good enough:

Water Heating Time Energy Power Cost Calculator
https://www.jinyi-solar.com/Solar_Basics/water-heating-time-power-cost-calculator.html

10-10-20

Hi, In my opinion you kind of need more than one sensor to monitor a tank, but I'm not sure how that will work with Google Home - whether you can combine them into a display to show the different levels of hot water available?

I have bought from Domadoo before and I find them good, except I don't know that brand of device. Would you consider a Shelly Plus with an add-on and then three sensors?

Basically, the add-on clips into the Shelly Plus 1 and you then power it all through the mains (so you'll have to wire it into a plug lead and place it into a box).

https://www.shelly.com/en/products/shop/shelly-plus-1

https://www.shelly.com/en/products/shop/shelly-plus-add-on/shelly-plus-add-on-3x-ds18b20

https://kb.shelly.cloud/knowledge-base/shelly-plus-1

That's roughly what I have (with Home Assistant), and I can boost the tank automatically then using another Shelly once the middle drops below 30c, for example:

Hope it helps.

Shoog

Built my own using an EPS32 and two Dallas single wire temp probes. All relatively easy with ESPhome and Homeassistant.

10-10-20

https://www.boards.ie/discussion/comment/122648576#Comment_122648576

Ah yeah, but that's even more advanced than wiring a plug. 😂

Chris_5339762

I use an Ecowitt Probe Thermometer

https://shop.ecowitt.com/collections/thermometer-probe-sensor

But you need a whole suite of Ecowitt weather station setups to do it. Works for me. Its not IN the tank, but is in one of the thermostat lines into the top of it.

Whats scary about actually seeing the temperature and graphing it is the sheer amount of heat loss.

GarlicBed

why not use the eddi relay/senor board ?

no messing around with 3rd party stuff