110/120V Charging - some questions

[Cottonwood]

The OP's condo association would likely have an issue with the Quick220 (and its other cousins) as it violates electrical code and creates some insurance and liability implications. See the FAQ in my signature, below, for more information.

Not to mention that the Quick220 will not work on 120 Volt GFCI outlets, which are required in all recent garage locations. In general, the Quick220 is not very useful...

 

[dave]

Does anyone have any data on how fast you charge at 120V in freezing temperatures?

I have a trip planned for next week, and I need to charge on 120V outside when the temperatures will be 10-15 degrees F overnight. I will have access to a 120V plug, but need to know if I'm going to be able to gain any miles at all with those temperatures.

Thanks!

 

[jerry33]

Does anyone have any data on how fast you charge at 120V in freezing temperatures?

Don't count on more than one mile per hour and be sure to plug it in and start charging as soon as you arrive so that the battery doesn't cool down.

 

[Electric700]

You may not need to know the actual kWh used, because unlike the Volt, your a Tesla will almost always be charging whenever it is plugged in. It's unlikely you will ever completely fill the battery at 120V if you drive every day. So could you assume it's plugged in x hours per day and pay on that basis? You can do the calculation for your area but at typical 10 cents per kWh rates a Tesla costs about 15 cents/hr to charge on a 15A circuit (12A charging).

Great points. You can also set up a scheduled time to start charging, and start/stop charging through the Tesla app.

Here's a usage example for 120 V at 12 A:

Voltage x Current = Power, so 120 V x 12 A = 1440 W or 1.44 kW. So if you charge for 12 hours, that gives you 17.28 kWh used, and at $0.10 per kWh you have the (Total kW Used) x (Cost per kW) = Total Cost, or 17.28 kWh x $0.10 = $1.73.

Enjoy your new Model S!

 

[wraithnot]

Indeed. I have a Kill-a-Watt but hesitant to use it this way as I was a bit scared of pulling a continuous 12 AMPS though this device for 10-12 hours while not attended. I'll look into it a bit more.

We've had a two EV house (S85 and BMW i3) since September and have gotten by just fine on two separate 120V circuits in the garage (although I can run a 50 amp extension cord through the kitchen and into the dryer outlet in a pinch). I got a WeMo insight switch for Christmas since the charge scheduling software on the i3 is terrible and haven't had a problem running 12A continuously through the WeMo. In addition, you can monitor the current draw and turn the switch on and off with your smartphone and have it email you a csv file logging your energy usage.

 

[theflyer]

Great suggestions, everyone. Thank you. My thoughts below.

You may not need to know the actual kWh used, because unlike the Volt, your a Tesla will almost always be charging whenever it is plugged in. It's unlikely you will ever completely fill the battery at 120V if you drive every day. So could you assume it's plugged in x hours per day and pay on that basis? You can do the calculation for your area but at typical 10 cents per kWh rates a Tesla costs about 15 cents/hr to charge on a 15A circuit (12A charging).

Simple and easy. I like this suggestion. The condo and I have agreed on 9 cents per kWh. I track the Association's energy usage pretty closely for them and our all-in average is actually a bit lower than 9 cents.

Could you make use of a Quick220? (Turns two 110s into a 220, Quick 220 Systems) Note that this won't on GFI outlets and the outlets need to be on different breakers. Steambrite makes a competing product.

No. Every outlet in the garage is on a single circuit and the other commenters raise many points that suggest it's not a very good alternative either way.

Are you in California? There is a law here that prohibits a condo association from disallowing installation of an electric car charger. You still have to pay the costs, but the association must allow it.

I wish. I'm in Virginia. I used the California law in our implementation plan/strategy document but it had no effect. Colorado is also taking a similar approach. It's quite frustrating.

Great points. You can also set up a scheduled time to start charging, and start/stop charging through the Tesla app.

Another great suggestion that provides additional options to TexasEV's suggestion. Cell phone coverage in our garage is very spotty. I wouldn't know whether this will work until I could test an actual Tesla in the garage to see if it is able to maintain a connection.

We've had a two EV house (S85 and BMW i3) since September and have gotten by just fine on two separate 120V circuits in the garage (although I can run a 50 amp extension cord through the kitchen and into the dryer outlet in a pinch). I got a WeMo insight switch for Christmas since the charge scheduling software on the i3 is terrible and haven't had a problem running 12A continuously through the WeMo. In addition, you can monitor the current draw and turn the switch on and off with your smartphone and have it email you a csv file logging your energy usage.

I'll look into the WeMo. Thank you for the suggestion.

 

[hiphenry]

I am also looking to plan to charge on 120V because it is easily available where I live and it's convenient. I do have the 240V option available but would rather not go there to set it up. Would anyone know if charging 120V at 12-15A be actually better than 240V at 40-50A in terms of battery longevity?

 

[TexasEV]

I am also looking to plan to charge on 120V because it is easily available where I live and it's convenient. I do have the 240V option available but would rather not go there to set it up. Would anyone know if charging 120V at 12-15A be actually better than 240V at 40-50A in terms of battery longevity?

No, it's not, and 120V charging is much less efficient. The car is really made to charge at 240V 40A or greater. If you have a 240V option available, by all means take it.

 

[Cosmacelf]

OK, any option to run an extension cord from your condo to the garage?

 

[theflyer]

OK, any option to run an extension cord from your condo to the garage?

No. That would be 10 floors and many concrete walls. When the Association finally decides its ready, there is more than enough extra capacity at the building's main breaker to pull a bunch of L2 circuits into the garages or outside spaces. I suspect all high density housing (Condos, apartments, residential HOAs) will have to support EVs eventually. It's just a matter of how long that'll be. 2 years? 5 years? My guess is 2018, 2020 at the latest.

 

[qwk]

Does anyone have any data on how fast you charge at 120V in freezing temperatures?

I have a trip planned for next week, and I need to charge on 120V outside when the temperatures will be 10-15 degrees F overnight. I will have access to a 120V plug, but need to know if I'm going to be able to gain any miles at all with those temperatures.

Thanks!

If you plug in right after arrival when the battery is still warm, there will be little difference in charge rate vs. warmer outside temperatures. If you let the battery get cold, you will not gain any range, and may even lose some.

 

[hiphenry]

No, it's not, and 120V charging is much less efficient. The car is really made to charge at 240V 40A or greater. If you have a 240V option available, by all means take it.

Thanks, TexasEV. Your info is consistent with another thread I found at Charging rates, current draw, and efficiency data for 120V charging.
Efficiency is one thing but longevity

 

[Moonwick]

Another idea for logging: What about using a kill-a-watt? The newest model has a built-in battery that will preserve the kWh counter while the unit is unplugged, and this makes it a reliable meter for measuring power usage.

 

[swaltner]

Before using a kill-a-watt, I'd contact the manufacturer and ask if they redesigned it to support 1.4 kW of power passing through it for potentially 3 days straight. There have been reports of the older models melting down due to the contestant draw of an EV. I just heard from a co-worker that his Volt induced a failure in a kill-a-watt on the 2nd charging attempt. At least the older models aren't up to the task.

 

[wk057]

Before using a kill-a-watt, I'd contact the manufacturer and ask if they redesigned it to support 1.4 kW of power passing through it for potentially 3 days straight. There have been reports of the older models melting down due to the contestant draw of an EV. I just heard from a co-worker that his Volt induced a failure in a kill-a-watt on the 2nd charging attempt. At least the older models aren't up to the task.

Yep, I blew up a Kill-a-watt with my volt a couple of years back. It lasted a couple of months, though, and died a week or so before I got a 240V/30A J1772 put in.

 

[Moonwick]

Interesting. I've been using a newer-model kill-a-watt on my Volt for the last year without any problems charging at 12A (yet!). It only needs to hold up until the 85D gets here in March, so we'll see.

 

[mikeash]

The Kill A Watt advertises 15A maximum current, so if it does fail under continuous 12A load you'd have an easy case for a refund or replacement under warranty.

 

[wayner]

@theflyer - Do you work in DC? Looking at PlugShare there appear to be tons of EV plugs in DC. Here in Toronto pretty much every office complex parking garage has at least two EV outlets. So maybe your solution is to do the bulk of your charging while at work.

 

[EarlyAdopter]

I wouldn't chance it with a Kill a Watt. While the warranty covers replacing the Kill a Watt if it dies, it explicitly disclaims any incidental damage. So if it catches fire and burns your house down, that's on your insurance.

Better would be to use the inductive clamp ring type power monitors. A TED or the like.

 

[wk057]

I wouldn't chance it with a Kill a Watt. While the warranty covers replacing the Kill a Watt if it dies, it explicitly disclaims any incidental damage. So if it catches fire and burns your house down, that's on your insurance.

Better would be to use the inductive clamp ring type power monitors. A TED or the like.

I highly recommend TED. I have two of these installed at home. (One unit for my two 200A grid-fed panels, and one unit for my two 200A panels that can switch between grid and soon off-grid).

They work well. The UI is a little complicated to setup at first, but it's not difficult.