EcoBee Smart Si Wifi Thermostat

Hey all,

New to the site as a member, but a frequent reader of many of the posts here.

I'm one of those that likes to tinker and tweak my trailer. And sometimes some of the mods lean more towards just my gadgety side vs practicality. So, some here may scoff at what I'm trying to do, but even if you don't see the practicality of it, hopefully you can still assist with the execution of it :)

A few year ago I upgraded from my standard analog Duo Therm thermostat to a Honeywell digital thermostat. Love it. Works like a charm and far more sensitive in maintaining a desired temperature. For anyone who hasn't done the mod, can't recommend it highly enough.

I'm currently working on taking the mod another step by installing an EcoBee Smart Si wifi thermostat. My trailer is parked at a campground and I have 24/7 free wifi. So, my summer 2016 projects are to make my trailer 'smarter' (again not necessarily practical, but more because I'd like to lol). I figured I would start with the thermostat, which would allow me to cool the trailer (or heat) prior to my arrival. So perhaps when I'm an hour away, can have the system get the trailer to the desired temperature.

The obvious problem is that the smart tstats run off of a 24v system and the Dometic air conditions are 12vdc controlled. At first, I thought that would be the end of the project, but have since come across a gentleman who did install one using 12v source from the Dometic and an EcoBee Smart Si. He claims (and is noted on the Ecobee site in a testimonial) that the 12vdc is enough juice to run the Ecobee.

My question is a) has anyone here tried this and b) I saw one homemade diagram (in the digital upgrade mod) showing the power coming from the Dometic as +7.5v vs +12v? I wont be at my trailer for a week to be able to take my meter and check for myself. But am curious is that is correct or not?

The second followup would be, if infact it WAS +7.5v vs 12v and I had to get 12v to the tstat (either via a common wire, or even external transformer) what effects would there be of sending a 12v vs 7.5v signal? Suppose worst case scenerio is blowing the control box which would not be good. But, curious none the less. I've yet to see a wiring diagram diagram anywhere showing 7.5v coming out of the aircon unit.

PS here is the link to the project page" ***Link Removed***

Thanks

Toddupton
Explorer
May 11, 2016
Yes you can run it off of 12 volts the other BIG question is the camps wifi will need an open port to the thermostat. I bet if you do a port scan on the park wifi you will not find anything open except a few like 80 and 441 maybe a few others. Not sure if the stat will connect to a public wifi like that or not. I would check some more documentation and see if it would work on a public wifi. Just my $.02
cargodog
Explorer
May 11, 2016
Thanks for your help! Re the wifi, I think I'll be good with the park as I connect directly to the main router. Plus, could always get an additional port opened up if need be - owners are pretty good that way. Don't think there is much of a firewall to deal with. And as an alternative, I could leave my Mifi hotspot there as the data consumption for the unit if constantly hooked up is 15/20 MB per month.

From what I'm reading (again, I'll test it likely next weekend) is that the Dometic control board takes the power from 12V down to 7.5V down to the tstat. But, since 7.5V won't be enough to power the tstat I'm thinking of just taking an external transformer to provide the juice and connect it (-12v) to the 'C' and (+12v) to the Rh/Rc jumpered position. Or finding some other constant source for 12v.

Sorry, just talking aloud to see if what is bouncing around my mind makes actual sense lol.

Thanks again! I'll certainly report on my outcome.
Toddupton
Explorer
May 11, 2016
You won't need another transformer, you can get the 12 from the stat wires, at least you should depending on how it is wired.
Chris_Bryant
Explorer II
May 11, 2016
The 7.5 won't be an issue, as it was just used by the thermostat itself, and was usually 12 anyway. The control signals back to the main board are all grounds with that setup. Most electronic thermostats are battery powered, so supply voltage is irrelevant, but I have no knowledge of the EccoBee

On edit, I looked at the EcoBee, and it's hard to say if it would work on 12 volt power. Worst case, wire in the pek kit.
TNGW1500SE
Explorer
May 11, 2016
I think you can overcome the voltage problem but port forwarding is going to be an issue unless you can get access to the campground router and set up port forwarding.

When you're on a campground network, you get assigned an IP address. If their IP was say 50.133.45.245 you'd have to ping a port on that IP like 50.133.45.245:7000 and that port would have to forward to your thermostat. Also you'd want a static IP address for your thermostat or every time their router rebooted, you'd get a new IP.

Correct me if I'm wrong.

One way that might work is to use a PC controlled relay (if you have a PC always on in the camper) and use google chrome remote desktop to switch the relay. You could even use a temperature switch in line with the relay.
Something like this maybe:

http://www.gearbest.com/development-boards/pp_63975.html?currency=USD&gclid=CjwKEAjwsMu5BRD7t57R1P2HwBgSJABrtj-R3jyc0Wwdn0gKtRlDeOG9EQLjSt9S3LWy4BxC26rQPxoC-_fw_wcB
rwbradley
Explorer
May 11, 2016
Port forwarding should not be a problem with this device. According to their documentation the device builds a reverse tunnel back to their mothership from your RV (via a common port like port 80 or 443). You then use the app or their website to tunnel back into your device via their site. This is common procedure for most new "Internet of Things" devices, so users do not need to know how to mess with their router. The only issue may be the initial connection of the device to the RV park WIFI, but I suspect it will not be an issue unless they are using something weird for security.
TNGW1500SE
Explorer
May 11, 2016
rwbradley wrote:
Port forwarding should not be a problem with this device. According to their documentation the device builds a reverse tunnel back to their mothership from your RV (via a common port like port 80 or 443). You then use the app or their website to tunnel back into your device via their site. This is common procedure for most new "Internet of Things" devices, so users do not need to know how to mess with their router. The only issue may be the initial connection of the device to the RV park WIFI, but I suspect it will not be an issue unless they are using something weird for security.

Interesting. So you just have to make sure the port is open?
cargodog
Explorer
May 11, 2016
Hey, loving the feedback guys. Very much appreciate all of them.

If I had to, I could access the router and have a PF done. And, as I mentioned, I also have the MIFI hotspot that I could leave there and do some work with. I believe that it has port forwarding, or the option to place a device in the DMZ. But, I'm not entire sure it's going to be required as in all the documentation they dont mention that detailed a router setup. So long as the originating router is handling DHCP.

I do also leave a laptop there, so will investigate the suggestion and option if I run into a road block on the connection side.

Power was my biggest concern, but since you gents have put me at ease on that, I'm full steam ahead.

Anyhow, I can't post the link here (links not allowed I guess), if you search 'Jane and John EcoBee' you can see the full breakdown of the guy who has it running in his RV with 12V (and EcoBee techs confirmed that the 12V would be enough juice to have it run). They're a Canadian company and have been doing really well here, I'm looking at getting some of their devices for the home.

Basically, he did a fairly simple wiring. Although he had a heat pump so there were a couple of grounds that were joined. But not the issue in my case. Planning on +12V to Rc/Rh jumpered, -12V to C, Yellow (cool) to Y, blue hi fan to G, furnace white to W, and that should be it on the wiring side.

I also have a ticket in with EcoBee support to confirm the 12V option. I'll let you know once they get back to me.
cargodog
Explorer
May 11, 2016
rwbradley wrote:
The only issue may be the initial connection of the device to the RV park WIFI, but I suspect it will not be an issue unless they are using something weird for security.

Nope just a standard WEP encryption from the router, and I get a full signal from my site.
rwbradley
Explorer
May 11, 2016
TNGW1500SE wrote:
rwbradley wrote:
Port forwarding should not be a problem with this device. According to their documentation the device builds a reverse tunnel back to their mothership from your RV (via a common port like port 80 or 443). You then use the app or their website to tunnel back into your device via their site. This is common procedure for most new "Internet of Things" devices, so users do not need to know how to mess with their router. The only issue may be the initial connection of the device to the RV park WIFI, but I suspect it will not be an issue unless they are using something weird for security.

Interesting. So you just have to make sure the port is open?

Port 80/443 are used for web surfing so they are always open and that is why they choose these ports. Any of these "Internet of Things" devices that ask you to access your device via an app or a website, usually do reverse tunneling. Basically the device phones home to the website when it boots up, your app phones home to the website and the website acts as a middle man to allow you to talk to your device. It is dead simple to use.

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