Non-Tesla BEV - What charger should I get to automatically stop charging during an outage?

[jamesb2147]

Hi all,

I'm sure I'm not the first person to run into this, but I'm struggling to find resources online. I just purchased a 2014 Fiat 500e which is as "dumb" as an EV comes; there's no connectivity anymore (yay 2G shutdown!), no scheduling on the car side, and no way to tell it to stop when a power outage occurs and we switch to the Powerwall for backup.

Anyone have suggestions on good chargers? Happy to use NACS + J1772 adapter, FWIW.

 

[EVRider-FL]

Have you looked into installing a new outlet that isn’t backed up? Might be too expensive, but worth a look.

 

[jamesb2147]

I have a detached garage, so expense would definitely be a real concern, and part of the reason I have the whole house on battery backup is to offer protection from fluctuations in power (the Fiat I bought, for example, has a small chance of dying if the power goes out while it's charging).

Anyway, after I posted this, I found a likely partial solution that I can hack around is the recently announced Tesla Universal Wall Connector. It appears to be capable of turning charging on/off (based on a schedule, per the marketing materials). I can use that with my utility's TOU pricing, and if I can get Home Assistant to eventually talk to it, then I can manipulate the schedule during outages so it won't charge during the outage. On top of all that, it serves my long-term goal of having NACS at home while also supporting the Fiat's J1772 port for charging today.

 

[jjrandorin]

I have a detached garage, so expense would definitely be a real concern, and part of the reason I have the whole house on battery backup is to offer protection from fluctuations in power (the Fiat I bought, for example, has a small chance of dying if the power goes out while it's charging).

Anyway, after I posted this, I found a likely partial solution that I can hack around is the recently announced Tesla Universal Wall Connector. It appears to be capable of turning charging on/off (based on a schedule, per the marketing materials). I can use that with my utility's TOU pricing, and if I can get Home Assistant to eventually talk to it, then I can manipulate the schedule during outages so it won't charge during the outage. On top of all that, it serves my long-term goal of having NACS at home while also supporting the Fiat's J1772 port for charging today.

I havent seen any Tesla branded charger have any sort of charging intelligence in it. I would verify and re verify (and re re verify) that what you are thinking you see about scheduled charging is actually a feature of the wall connector (because I dont think it is).

Tesla does not have any current solution for charging a car during TOU periods, with or without Tesla branded cars and chargers, even working together. Tesla scheduled charging is done from the car side, not the wall connector side, and even though you can put time of use time frames in the Tesla app, the car will either start charging on a schedule, or FINISH charging on a schedule, but will not (with any tesla only solution) charge ONLY during a particular schedule.

TL ; DR is I dont think the proposed solution is going to work. I am not 100% sure, and it might be possible with some third party tools to try to program around it or something, but It isnt going to work with any sort of scheduling that Tesla provides itself.

Tesla powerwalls also dont obey any sort of battery reserve level when off grid. I am pretty sure thats because if they did, if someone had a 100% reserve and the power went out (a fairly common setup), they would have to take some action in order to get power to flow, which defeats the purpose many people put in powerwalls instead of generators.

 

[cali8484]

Anyway, after I posted this, I found a likely partial solution that I can hack around is the recently announced Tesla Universal Wall Connector. It appears to be capable of turning charging on/off (based on a schedule, per the marketing materials). I can use that with my utility's TOU pricing, and if I can get Home Assistant to eventually talk to it, then I can manipulate the schedule during outages so it won't charge during the outage. On top of all that, it serves my long-term goal of having NACS at home while also supporting the Fiat's J1772 port for charging today.

If you are comfortable with HA level of scripting then you might consider OpenEVSE. It has a simple API to start/stop charging and set charging current limit. It should be straight forward to create script to monitor PW status and turn OpenEVSE charging off in blackouts.

 

[h2ofun]

I havent seen any Tesla branded charger have any sort of charging intelligence in it. I would verify and re verify (and re re verify) that what you are thinking you see about scheduled charging is actually a feature of the wall connector (because I dont think it is).

Tesla does not have any current solution for charging a car during TOU periods, with or without Tesla branded cars and chargers, even working together. Tesla scheduled charging is done from the car side, not the wall connector side, and even though you can put time of use time frames in the Tesla app, the car will either start charging on a schedule, or FINISH charging on a schedule, but will not (with any tesla only solution) charge ONLY during a particular schedule.

TL ; DR is I dont think the proposed solution is going to work. I am not 100% sure, and it might be possible with some third party tools to try to program around it or something, but It isnt going to work with any sort of scheduling that Tesla provides itself.

Tesla powerwalls also dont obey any sort of battery reserve level when off grid. I am pretty sure thats because if they did, if someone had a 100% reserve and the power went out (a fairly common setup), they would have to take some action in order to get power to flow, which defeats the purpose many people put in powerwalls instead of generators.

I guess in some ways maybe my wall connectors not being connected to my batteries might be a plus? I can only charge my EV from excess solar going back to the grid, or the grid, never the batteries.

 

[jjrandorin]

I guess in some ways maybe my wall connectors not being connected to my batteries might be a plus? I can only charge my EV from excess solar going back to the grid, or the grid, never the batteries.

Everyones situation is different, but I dont see it that way. My wall connectors are setup on the non backed up loads side, however I actually had ADDED a 14-50 outlet on the backup loads side.

The reason for this is, IF i was in a power outage, and IF my batteries were getting full and I wanted to have my solar NOT curtail its production, I can plug in one of our EVs and use that power to charge the car (keeping the PV producing).

Im not one to tell others what is right for them, but I wanted this flexibility to be able to use, or not use PV to charge my cars if I was in a power outage. A bunch of "ifs" there and certainly an edge case but If I was in your situation, with as much PV as you have, if I was in a power outage, I would want the PV to keep producing as much as I could (and use that power wherever I could).

 

[jamesb2147]

If you are comfortable with HA level of scripting then you might consider OpenEVSE. It has a simple API to start/stop charging and set charging current limit. It should be straight forward to create script to monitor PW status and turn OpenEVSE charging off in blackouts.

That's a fair suggestion, though the Tesla chargers have the added benefit of being able to intelligently "share" an overall charging limit (e.g. 100A service to garage would mean I can't setup 48A on 2 chargers due to 20% safety margin, unless I get the Tesla ones and configure a max shared of like 80A). Something I'll check out, for sure, as official support and an API may be worth the tradeoff of lower peak charging speed since I'm still well into L2 charging territory.

I havent seen any Tesla branded charger have any sort of charging intelligence in it. I would verify and re verify (and re re verify) that what you are thinking you see about scheduled charging is actually a feature of the wall connector (because I dont think it is).

Tesla does not have any current solution for charging a car during TOU periods, with or without Tesla branded cars and chargers, even working together. Tesla scheduled charging is done from the car side, not the wall connector side, and even though you can put time of use time frames in the Tesla app, the car will either start charging on a schedule, or FINISH charging on a schedule, but will not (with any tesla only solution) charge ONLY during a particular schedule.

TL ; DR is I dont think the proposed solution is going to work. I am not 100% sure, and it might be possible with some third party tools to try to program around it or something, but It isnt going to work with any sort of scheduling that Tesla provides itself.

Tesla powerwalls also dont obey any sort of battery reserve level when off grid. I am pretty sure thats because if they did, if someone had a 100% reserve and the power went out (a fairly common setup), they would have to take some action in order to get power to flow, which defeats the purpose many people put in powerwalls instead of generators.

I think it's prudent to wait, and I will be waiting months so I will get confirmation before purchase. That said, it does seem like I'm not alone in my understanding:

Tesla Launches a Home Level 2 Charger for Both J1772 and NACS Plugs

This new home charging unit will also allow control and energy monitoring through the Tesla app for the first time.

www.caranddriver.com

The other major change is that, through the Tesla app, users will be able to schedule or stop and start charging and view charging history and energy usage for the first time.

https://shop.tesla.com/product/universal-wall-connector

• Monitor and manage your charging schedule and usage from the Tesla app

Note: Tesla app features will be available starting later this year.

 

[jjrandorin]

That's a fair suggestion, though the Tesla chargers have the added benefit of being able to intelligently "share" an overall charging limit (e.g. 100A service to garage would mean I can't setup 48A on 2 chargers due to 20% safety margin, unless I get the Tesla ones and configure a max shared of like 80A). Something I'll check out, for sure, as official support and an API may be worth the tradeoff of lower peak charging speed since I'm still well into L2 charging territory.


I think it's prudent to wait, and I will be waiting months so I will get confirmation before purchase. That said, it does seem like I'm not alone in my understanding:

Tesla Launches a Home Level 2 Charger for Both J1772 and NACS Plugs

This new home charging unit will also allow control and energy monitoring through the Tesla app for the first time.

www.caranddriver.com

https://shop.tesla.com/product/universal-wall-connector

Never, ever (ever) buy any Tesla product on features that are "coming later". Either buy it or dont based on what it does right now.

Tesla vehicles currently "Schedule, or start or stop charging" currently, but in no instance does it start and stop to coinside with Time of Use settings. Its "Schedule charging to start at a certain time" or "Schedule charging to end at a certain time" or "start charging with a button in the app", or "stop charging with a button in the app".

I could point you to a few different threads with people complaining specifically about the fact there is no integration with TOU settings, but in any case I will just say its not the best idea to buy ANYTHING tesla related based on "what it is going to do in the future". I have tesla cars, powerwalls and solar, and I like them all, but I also would tell people to never, ever, buy anything based on promise of future functionality.

 

[jamesb2147]

Never, ever (ever) buy any Tesla product on features that are "coming later". Either buy it or dont based on what it does right now.

Tesla vehicles currently "Schedule, or start or stop charging" currently, but in no instance does it start and stop to coinside with Time of Use settings. Its "Schedule charging to start at a certain time" or "Schedule charging to end at a certain time" or "start charging with a button in the app", or "stop charging with a button in the app".

I could point you to a few different threads with people complaining specifically about the fact there is no integration with TOU settings, but in any case I will just say its not the best idea to buy ANYTHING tesla related based on "what it is going to do in the future". I have tesla cars, powerwalls and solar, and I like them all, but I also would tell people to never, ever, buy anything based on promise of future functionality.

Sage advice, which I do intend to follow, to be clear

 

[arnolddeleon]

TLDR, I recommend "Home Assistant" (Home Assistant) as the platform to build you automation around and doing an Internet search for "EVSE Home Assistant"


I haven't bought any EVSE's lately so I haven't done recent research, but I can offer general advice.

You want to find an EVSE that has an API that will allow you to control it. Preferably a local API since in a grid outage you may not have internet access.

I'm pretty sure an OpenEVSE based one will have it. I currently have a JuiceBox and I believe it has a cloud-based API. I haven't checked recently to see if it has local API.

You will need something that can detect you have a power outage. Something like "Home Assistant" has an integration that will talk to the Powerwall so you can have automation that will trigger to turn off charging.

You can also do this by hacking on the EVSE, you can simple "break" the pilot signal when you detect the power outage. I suspect if you had ability to do this you wouldn't be asking the question.

This particular project initially fell off my Todo list when I just accepted the fact that if my batteries got emptied overnight, I will just have them charge with sunshine the next morning (after unplugging the car). I also had switched to basically charging during the day anyway, so it become somewhat moot, I was going to be awake. And not too long ago, Tesla made it unnecessary since I have Tesla vehicles and they know to stop charging.

 

[woof]

Probably not useful for the original poster, but for others who are planning whole house battery backup, consider upgrading the breaker panels to something like SPAN® Home | Harness your power They allow software control of which circuits are powered during battery operation, including app/API control in real-time.

 

[ucmndd]

What is your powerwall setup like? This is where I think you have the best opportunity to do what you want.

Do you have a gateway 2? Does your install use the internal panel board for anything? My install is essentially “whole home” where the main breaker in the gateway feeds a load panel that has basically the whole house on it, EXCEPT my hot tub and non-Tesla EVSE, which land on the internal gateway panel and are not backed up.

 

[wwhitney]

You can also do this by hacking on the EVSE, you can simple "break" the pilot signal when you detect the power outage.

Which pilot signal should be broken, control pilot or proximity pilot? I was thinking that breaking proximity pilot would be a bad idea, as I imagine (just based on the name, not studying the protocols) it might let the EV drive off with the cord still connected.

Will breaking the control pilot cause the EV to stop charging, and then cause the EVSE to open its contactor a little while later? Is that guaranteed by the J1772 protocol to work across all EVSEs and all EVs?

There are least a few internet hits for a "man-in-the-middle" type remote control device for the control pilot, to allow changing the PWM rate to 0 allowable charging current, but I'm not aware of a simple commercially available solution.

Cheers, Wayne

 

[cali8484]

That's a fair suggestion, though the Tesla chargers have the added benefit of being able to intelligently "share" an overall charging limit (e.g. 100A service to garage would mean I can't setup 48A on 2 chargers due to 20% safety margin

Sure you can. People have done various charge sharing configs. You can script the OpenEVSE's to shutoff one or more OpenEVSE off or just limiting max current limit (different or same limit for each if desired) so all EVSE's can charge.

 

[yblaser]

I have a detached garage, so expense would definitely be a real concern, and part of the reason I have the whole house on battery backup is to offer protection from fluctuations in power (the Fiat I bought, for example, has a small chance of dying if the power goes out while it's charging).

There is a high likelihood that the system will not switch seamlessly in the event of the power outage. You can expect anywhere from an instantaneous switch to 10s of seconds depending on the state of the system and the nature of the interruption. I wouldn't rely on it to protect anything where a power interruption would cause damage.

 

[tomuo]

I automate an OpenEVSE directly from Hubitat, currently matching charge rate to excess Solar production.
That works great, but some vehicles don't respond well when the pilot goes off. They will stop, but my i3 reports an error if it turns on and off a couple of times back to back. Better to modulate it down to minimum (6A@240V) and take the hit of it charging from the home battery.
OpenEVSE supports multiple charging periods which you can use to lock out of high ToU rates, but the API doesn't let you change those remotely except through the web page which is not automatable.

 

[GregBallantyne]

To the OP -
I recently started using Charge HQ after getting my solar/battery system into operation, as I noticed that car charging got more complicated. My initial desire was to charge on excess solar. Of course after using it, and having a 3 day grid outage, I asked the developers about a grid outage stopping car charging. I was told that was going on the to-do list. But in my case, the car is a Tesla and Charge HQ communicates with the car, not the wall connector. There is a list of supported charger for Charge HQ I believe. Check out the list of supported chargers, there may be a solution for you in that app paired with a supported charger.