HA for Solar/batteries, Energy, HVAC, and potentially others. What devices/system would we be looking at?

Hardware
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New to HA. Wanting to do some monitoring/control and HA looks quite interesting and capable. I don’t know much about it yet, so looking for ideas and input – point me in some viable directions!

What device(s)/system would you suggest for our needs? It sounds like a mini computer may be the way, like N100? But I don’t know what specs are needed. Want something that’s dependable though.

Some potential areas HA could be used, the main things being the solar inverter/battery systems and heating:

1. Solar inverter (Sol-ark 15k and Pytes battery grid-tied; SRNE and JK BMS off-grid)

Better monitoring and control (Sol-ark app isn’t great, but also dependent on internet/Sol-ark).

For example, adjust how the inverter and batteries function (export/import) according to the hourly electricity price.

Some people use Solar Assistant for this, but I’d rather avoid their pay model. I’ve seen people doing other ways, I think it involved ESP Home (not familiar with that).

2. HVAC - 2 stage heat pump (heat/AC), possibly electric resistive heat. Plus separate propane boiler in-floor heat. HRV.

For example, adjust heating based on electricity pricing. Be able to adjust how the thermostat operates (e.g. increase differential so it cycles less, or use other sources if outside temperature is cold).

  • I wonder if a “making” a thermostat (temp probe and output contacts) would be the better way (compared to trying to find a compatible thermostat).

3. Energy/power monitoring/control - The inverter has data on the whole house and its own function, but possibly could do some individual circuits like the heat pump, or there’s a separate accessory building that is not part of the house system.

4. Reolink cameras - 5 outdoor cameras with Reolink NVR. Not sure if there’s a practical way to integrate/improve this with HA. We still need to figure the detection out better as we’re getting too many false notifications.

5. Accessory building (garage with small apartment) - possibly monitor temperature/humidity, water leaks, and do things with heating, energy monitoring, etc.

This is on the same LAN as the house, connected with (private) fibre link. So devices here would not be able to connect directly to the HA computer, and need to connect through the LAN. Not sure how that’d work - are there devices that do this, or would we be looking at another Pi/computer for a separate building?

Other thoughts.

Internet firewall/filtering - not sure if this could relate into HA, or maybe the mini computer can help do this (or should be separate device)? And/or I wonder about content filtering, like ads?

Also wonder about local voice control.

Let me know your thoughts!

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You should start to see if the physical “things” you want to integrate can be connected to HA in some way.

The inverter and possibly the batteries should be interegrable via Modbus from the superficial search I’ve done.

For HVAC system you should look at your make/model to understand the way to start/stop them and thermoregulating. Usually the first part is rather simple, many appliances have dry contact input ports that can be managed by a smart relay/switch. The regulation is more complicated as it involves working ithe internals of the appliance. There are ways, look at your devices if these support open/documented protocols (modbus, open therm, eBus).

And so on for the video and climate regulation.

One important aspect is the network connectivity you want/need. In my personal view if you plan to have connected few dozen of devices (plugs switch, appliances etc) WiFi is better. If you think you need more you should think to a mesh network (zigbee??)

The other choice you have to make is the type of hw that you should use to run HA on. If you think you’ll need video processing (CCTV) or local AI/voice processing you’ll need more resources.
Otherwise for a medium to large installation any x86 device will do. A used NUC will be my starting point, I run my system (60/70 devices with PV, HVAC and various switches, plugs and thermostats) on a refurbished 10 years old thin client with 4GB ram the cpu usage is negligible and the power consumption follows suit.my choice was motivated by the price tag, for few euros I bought 2 and so I have a failover system.

This in turn brings the most important thing that in my view you must plan in advance: what you will experience when, having HA running for some time, it will suddenly/eventually fail. The motives of the fault can be many but the most common will be that during some upgrade something breaks.

It’s inevitable as HA is one of the most actively developed piece of software available. You should not rely on HA for basic functionality of your house. Leave to it the thing it can do better: smartify things (start the EV charging on surplus PV production, create complex scenes and so on).

1 Like
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Thanks for the response.

I know people have integrated Sol-ark inverter, I just don’t fully understand how (yet). It would be through the RS485 or possibly RS232. I’ve seen some involving usb to rs485 or ESPhome.

Pytes battery I’m not sure. I’ve connected to it from my laptop with a console cable, updated firmware, checked cell level info. The SRNE and JK BMS I don’t have yet, but I believe they are RS485 as well.

So the several main items (6 or so) are RS485. And thus need a system that works good with that, preferably units that can do multiple RS485 (since each inverter is paired with battery).

The heat pump, while it is an inverter model that can have a proprietary wall control, for whatever reason it was installed with a basic thermostat. I.e. R/C/G/Y1/Y2/W etc. terminals. The propane in-floor and resistive heat is similar. To get the customized schedules wanted is difficult with a standard thermostat, so I’m thinking best means a temperature probe and dry contact outputs to accomplish it. (recommendations on these parts would be helpful)

The electricity monitoring would be on selected circuits in a couple electrical panels. Probably some other temperature probes.

Otherwise, we aren’t wanting to do much, if any general devices - no plans to do general receptacles or light switches, or household appliances, for example.

For fallback on HA failure, my thoughts are the inverters would keep operating (with last settings) and could be connected back to internet to use the manufacturer’s dongle. I would leave the existing thermostat in place as a fallback.

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Your RS485 bus traffic could be placed onto your LAN network with a simple converter. All the RS485 devices can talk on the same bus, but you could have two converters on two buses and two converters if the RS485 equipment is present in both of your buildings if you don’t want to take advantage of the 1km capability by running added wires between the buildings, and both your converters can happily talk to your HomeAssistant box over the existing LAN network, saving you the longer wiring run for RS485 cabling.The secret is to make sure that every single device has an unique address, so you will have to dig down in the documentation to find out how to do this rather than hope the default settings work - they most likely will clash. Write down each device settings, both default and desired, makes for efficient planning and easier troubleshooting later.

Both RS232 and RS485 are serial protocols. Most converters will support both. Mix and match may be possible, but you need to read the documentation carefully. In all cases with RS232, TX goes to RX, and your settings such as baud rate, stop bits and parity have to match. This is often a gotcha for beginners.

Don’t forget to move the jumper or add the obligatory termination resister if you have more than one device on your RS485 bus. Only one on each end is needed.

Rather than reverse engineering your thermostat protocols, try emulating your remote control button presses, and getting feedback via alternate sensors such as temperature/humidity may be an option.

Dry contacts for controlling your equipment is simple. A multi port relay should do the job if you can run wires to one location, otherwise you will have relays/switches everywhere.

Using the cloud to monitor and control your devices can be easy, but consider what happens when you lose connectivity, or the vendor changes or pulls their cloud access, or decides to charge you a monthly access fee. Sometimes there is planned obscolescence that add-ons in HomeAssistant can bypass.

You have listed quite a number of issue to consider. Solve them one by one, HomeAssistant being the powerful part to glue it all together.

Just some suggestions to consider.

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In your case I’d go for RS45 to wifi media converter, these “talk” ModbusRTU on the wired serial interface and ModbusTCP over the wifi one, having done that it’s simple to get the data in HA via custom integration for the “known” devices and via native modbus for the devices that don’t have a pre-built integration. For the latter you’ll need modbus register maps but it’s usually available from the producer.

The cost of the converters is not high, depending on your system you may need more then 1 converter (I think 1 for each inverter and 1 for the BMS). Modbus is a Bus so theoretically you could wire all the device to a single adapter if the wiring allows it and if you can change the adresses of the devices to avoid confilcts.

Having a fair number of modbus devices you should try to document and leard a bit about the protocol, this will facilitate your installation of HA.

I’m based in Europe so I’m not familiar with that kind of thermostats, here we usually have 4 wires, 2 for power (if not on batteries) and a couple for the dry contact.

Post here the make/model of the HP and the thermostats. HP usually have a Modbus port to integrate it with building management systems. It’s the usual access key to change system parameters (see, Modbus came back again)

There are wifi/zigbee thermostat integrable with HA, search the forum for suggestions, it can be that you can swap the basic one you have for a smart one, then use it to start/stop/set the temperature for your appliances. HA can integrate and monitor and smartifying the usage but the day to day ops will be left to a pourpose built device.

Yes good call. See above for the alternative.

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I imagine there are RS485 to ethernet as well if we wanted wired. The Sol-ark/Pytes pair, and possibly one SRNE/JK pair, as well as the heat pump, etc. are in the same room as the router/switch and where the HA would go. Does it still make sense to go over ModbusTCP when it’s trivial to run a wire to HA directly (connect via USB or something?)?

The other SRNE/JK would be in the other building - so definitely makes sense for ModbusTCP there.

Ya definitely need to get up on the modbus protocol now that it seems determined that is the main devices here. That’s part of why this post, to get some direction to research. Do you have any resources to recommend?

For the heat pump, the best I can see is CMNA in Kennesaw GA (made in China). The models are

Heat Pump (outdoor): DLCSRBH30AAK
Fan Coil (indoor): DLFSABH30XBK

If you look at the manual, it will show an included wall control and remote, but for whatever reason it’s not here. It’s wired as “Third party heat pump thermostat” 24V,
Using the thermostat: Honeywell TH8320R1003

Interestingly, in the fan coil manual, it shows “light commercial units” fig. with non-polarity RS485, but ours is a “residential units” without that shown.

The in-floor heat is just a basic TH1100DV1000/U type.

Since these stats basically operate like dry contacts, it could be replicated with a temperature probe and dry contacts on HA, if the code could be developed (I think I saw HA code somewhere like this). That way can also put everything (HP and in-floor) on one control.

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Some internals on heat pump and thermostat in question.

Heat pump board
Heat pump board1872×4160 574 KB

thermostat board
thermostat board1920×864 105 KB

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You can use a USB to RS485 converter and use serial communications, these are cheap too.

Not really, I have a very basic knowledge started with a google search…

From the model numbers these appears as Midea devices (maybe rebranded) from the superficial search I’ve done these unluckily lacks Modbus support, take a look at the manual to confirm this…

If it is confirmed the solution I’d look at is a smart thermostat that has local access support.

Take a look here:

The same solution should be applicable for the in-floor heating, but remember, I’m out of my league with USA(?) standards…

That would leave you cold (or hot) if HA goes down, I’d invest some bucks in a couple of dedicated thermostats that you can manage via HA.

Recap: the PV devices (inverter, batteries etc) should be “easily” integrable via Modbus, the cooling/heating devices, being “basic” and lacking the possibility of in depth manaement (eg. change the flow temperature based on the outside air temp) in my poor opinion should be integrated using dedicated and independent wifi thermostats.