Device Detection Major Update: Chevy Electric Vehicles - 10/11/18


#61

Here is a link to a HS110 Teardown.

https://www.edn.com/design/consumer/4458082/Teardown--A-Wi-Fi-smart-plug-for-home-automation

I think @Ipearce point was that the HS110 it intended to be used on a system with only one hot wire, one neutral and one ground. In the US this is only for 120 VAC as 240 VAC has 2 hot wires using our split phase system. It may work but it will not meet US electrical code, in my opinion.

To confirm, the HS110 relay, the Omron G5RL-1A-E-HR is a single pole relay with high inrush and a 16 A at 250 VAC rating so is will handle the current.

When you cycle power to your HS110, that is connected across the 240 VAC split phase, your charger will still have power on one of the hot wires in relationship to neutral. Your charger may not be charging but it will definitely have one side of the split phase still hot inside your charger. This is causing the charger to to see a non-normal state and it could still be powering up control circuits, etc. Since this current would be on the non-monitored side of the HS110, I assume it would just show up in “Other”.

I think this a very cool workaround for your issue with detecting two Volts but it’s not “safe” by government standards, IMHO. :grinning: It might even void the warranty of your EVSE?? Did you wire a 120 VAC duplex outlet to your 240VAC feed to plug in the HS110 and then put a 120 VAC plug on your EVSE so you did not have to hack the HS110? That’s what I might do. Hacking the HS110 and putting 240 VAC plug on it would allow you to keep your house to code?? hummm I would not let my county electrical inspector see this and please consider removing the plug if you move. If you did the HS110 install differently for your 240 VAC installation, I’d be interested in hearing about your setup.

My $0.02,
Jerry


#62

oshawapilot
lpearce

I’m thinking a 240 VAC double pole disconnect with current monitors on both phase legs (sorry, both sides of the split phase) could be built. Use two HS110s wired correctly (both neutrals tied together). Either hack them or use 120 VAC plugs and receptacles to wire it pretty in a box.

I assume you could turn on/off two HS110s at the same time, (maybe auto link them?) so that would solve the issue of the charger still having one side hot. Maybe you can “combine devices” for two HS110s on the Sense, idk?.

I’m thinking about this one side of the split phase being hot with the other side open on the EVSE. This is also happening in your charger in your car, unless the EVSE is smart enough to know it’s missing a hot wire with only one HS110 open and shuts itself down to protect the EV???

Since you are not getting any faults on the car’s diagnostics, I assume you are not hurting the car but it is a non-normal state, IMO.

To be clear, I would not change a thing as your fix was so clever, I’m just being the “devil’s advocate” here. :neutral_face:


#63

Update: I found a tare-down of the 240-241 volts, what ever it takes, European version of the HS110.

https://curesec.com/blog/article/blog/The-HS-110-Smart-Plug-aka-Projekt-Kasa-165.html

Unfortunately, it does not solve the open issue of leaving one side of the split phase hot when using a HS110 to control a US 240 VAC device. It uses the same, single pole relay as the US version.

The only advantage to this unit over the US version is that it would “look safer”. You could wire up a standard 240 Volt USA outlet near the charger, then use pass thru converter plugs to plug in this 100-240VAV 16A version. Then another pass thru converter to a US 240 volt plug for the EVSE.

Edit: As pointed out by kevin1 this idea does not give you a neutral connection to the charger. This needs some thought and vetting before it implemented. IIRC, the rectangle pin on the European version is a separate wire to ground and the round pins are a floating 220/240 VAC.

Without a proper neutral and ground connection to a US, 240 VAC charger I can see several potential issues. For example the EMI “Y Caps” from the hots to ground would not work as intended. ETC!

Don’t try this at home.

Edit 2: Ignore Edit 1: I now see that SAE J1772 only has two lines for input voltage and one ground. As others have said, SAE_J1772 is dual voltage so one side is connected to neutral when connected to 120 VAC. When connected to a 240 VAC EVSE. I now see that there is no neutral, just two hots and a ground.

Back to the main point of my post: When using a HS110 to control a 240 volt charger, it will leave one of the split phases hot on the charger. Since the charger input voltage is double isolated from humans there is minimal risk, IMO. I stand by the fact that normally a double pole relay is used to control 240 VAC loads.

European version:

UK Version:
image


#64

I can’t think of an issue if:

  • the HS110 is always turned on
  • the EV charger doesn’t require a neutral connection (most I have seen, don’t)
    The charger is presented with exactly what it expects from the wall outlet.

#65

I would suggest we verify this. Floating the neutral may not work on some chargers and I’m sure it’s against code. Either way, you have pointed to out a flaw in the idea of using a 230 volt version of the HS110 in the US. You would not get the required neutral to make it pass code and function. I’m sure some charges require neutral! I’m going back to the idea of using two HS110s, one for each side of the split phase as a safer way to do this trick.

IMHO,
Jerry


#66

Agreed. I know all my various Tesla chargers have no need for a neutral, but they sink way too much power for use with the HS110.


#67

Just thinking out loud here. You could hack a HS110 to control a double pole 50 amp relay to control most loads safely. It would be much harder to hack the HS110s current monitor to make it work past 16 amps. hummmm

Good night,
Jerry


#68

That thought has crossed my mind :wink: But I think there are a few other weak links, beyond the relay.

  • the traces on the board
  • the shunt resistor / CT in the power measurement front-end

I was thinking about ways to wire up a NEMA 6-50 outlet that doesn’t go through the relay but does use the measurement part of the HS110.


#69

The Bosch/GM EVSE for my Volt doesn’t have a neutral conductor connection at all. I don’t see why any of them would.


#70

EVSE’s require a ground, all will fault without it. Onnthe topic of neutrals, Only 120v specific models may require a neutral, but the EVSE’s included with most EV’s are now actually dual voltage even when they may only purport to be 120v “travel” models, so in short, they still likely don’t need neutrals.

Many of the first gen Volts included 120v only EVSE’s which indeed were most certainly not dual voltage. We have one. I could test the theory of if it requires a neutral connection to work or not.


#71

I should clarify: my EVSE is a 240v level 2 charger. Any 120v EVSE for use in the US will require a neutral. I can’t think of any reason a 240v EVSE would need a neutral, though.

And yes, a ground is required for every EVSE I’ve seen, and the unit will verify that it’s a solid ground as part of its built in self test.


#72

Update: I’ve dedicated an always on HS110 to monitor the Volt during charge cycles. And for the fun of it I borrowed a FLIR thermal camera to monitor HS110 after an hour of the Volt charging at 3.1kWh (208V@14.9A). It does appear, at least externally, the HS110 can handle at least 15A continuously without any significant hotspots.

And while I was at it I also connected two HS110 in series to read OFF and ON power consumption:
HS110 OFF: 1.4w
HS110 ON: 2w

Also noticed my EVSE (Dousida) takes 1.2w when in standby/idle.

And it seems my Volt is not that efficient at charging, a single partial cycle to full, Volt reported 4.3 kWh used and Sense via HS110 reported 5.8 kWh for the charge cycle. So 4.3/5.8 = 74% efficiency. I thought it should be closer to 85%? I wonder if a full charge cycle will be more efficient?


#73

I mispoke. You are correct, IMO. I now see that SAE J1772 only as two lines for input voltage and a ground. As others have said, SAE_J1772 is dual voltage so one side is connected to neutral when connected to 120 VAC. When connected to a 240 VAC EVSE. I now see that there is no neutral. My bad.


#74

This has been discussed at length on many other forums. The Gen1 is around 80% efficient, Gen2 is around 87-88%.

It’s also well known that the Volts (especially the Gen1) onboard kwh consumption display is often optimistic, so you probably did actually use more than 4.3kwh.


#75

I’m just curious, are you in the US getting 208 VAC off a singe phase from a 3 phase system? I assume this is not a residential setup??


#76

Interesting, my understand was only the miles left were inaccurate (guess-o-meter). However I would think the amount of energy consumed should be very accurate since most likely they are measuring the current via CT or shunt. My bet the charging efficiency is impacted by the ambient temp, winter should be worse than summer. Requires more energy to charge a colder than a warmer battery (not hot battery)?


#77

Correct, 3 phase power but it’s residential in California. Actually I wish I had access to 240V for faster and slightly more efficient charges.