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Unplug 14-50 Adapter or leave it plugged in all the time?

I’m getting ready for my M3 delivery and having my electrician install a Nema 14-50 outlet. I purchased the KELLEMS HBL9450A, my question is; im reading how a lot of forum members have discussed not to unplug the adapter from the outlet. What’s the best thing to do? Unplug it or just leave the charger connected all day everyday? Thanks everyone
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
17,461
23,384
Riverside Co. CA
That recommendation (to not unplug the mobile connector all the time) is because:

1. It not usually necessary to carry the mobile connector with you all the time
2. "Cheap" 14-50 outlets normally purchased at a big box type hardware store tend to not be as robustly designed as far as the tension in the outlet, for repeated "plug / unplug" cycles.

Googling that outlet you say you purchased, it looks like an industrial type outlet, so point 2 should not be in play. I am not an expert in this by any means, but it appears like its one of the hubbel ones.

So, you can unplug it however you want to, but there isnt really much reason to do so. You dont have to carry the mobile adapter with you every day.
 
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The recommendation is most certainly to not plug and unplug it from the outlet frequently, even with a very good quality Hubbell outlet.

All the information you could ever want on 14-50 charging is in the thread below:

 

Frank99

April 2018 Model 3 LR RWD, EAP, FSD
Apr 7, 2016
402
554
Arizona
Even a good quality outlet will eventually wear out with lots of plug/unplug cycles. I have a couple of 120V outlets in the house that need replacement for that reason - I'll get to it someday. If you want to plug/unplug daily, assume you'll have to replace the outlet in 5-10 years. But, frankly, unless you're an unusual case, you'll quickly find that you simply don't need to - the car will have enough battery capacity to get you through your day, and on road trips you'll almost always just use a Supercharger. I plugged my mobile connector into the wall almost 4 years ago when I got my Model 3, and it hasn't been unplugged since.
 
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Plugging and unplugging frequently may eventually wear out the outlet.

You probably don't need to do that anyway. For normal daily use, just leave it plugged in. You can unplug it and take it with you for infrequent road trips where you may want to use an RV park 14-50 outlet or other outlet that you have the adapter for. But Superchargers may be more convenient on road trips anyway.

If you have a frequent need to keep the mobile connector in the car, you may want to get another one to leave plugged into that outlet in your garage, so that you do not have to keep plugging and unplugging.
 
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RayK

Safety Score 90 (Was 96!)
Apr 5, 2016
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San Jose, CA
Thank you all for the responses. When talking about leaving it connected. Do I leave the adapter connect only
Or the entire charger ?
I would leave the entire mobile connector and NEMA adapter attached to the outlet. If you disconnect the mobile connector and leave the NEMA adapter plugged into the socket, then there is a (remote) possibility that electrically "hot" terminals will be exposed at the end of the adapter. It would be like disconnecting the A/C cord from an AC adapter that you would use with some equipment, such as a laptop, and leaving that cord always plugged into the wall. Sure those terminals are recessed into the body of the NEMA adapter but why take a chance?

Yes, there may be some nominally small amount of power (couple of watts?) being consumed by the mobile connector when it's plugged in but it's similar to most of the other vampire drain that occurs in your house. If you are concerned about the extra power being lost, you can probably compensate by finding a couple of USB AC adapters that are always plugged in and unplug them when you're not actively using them. Or, if the outlet is the only thing connected to the breaker, flip the breaker off when you are not charging.
 

RayK

Safety Score 90 (Was 96!)
Apr 5, 2016
3,147
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San Jose, CA
Are breakers intended to be switched that frequently? I would worry that this was moving too much cycling of the receptacle to too much cycling of the breaker. But I have no clue which is better.
Hmm... after some searching of the collective human knowledge (i.e., Googling), it appears that treating a breaker like a simple wall switch is NOT recommended. I hereby withdraw my suggestion. If the idle / standby power draw is concerning to you, then unplugging the adapter is the best approach. You can probably get several hundred plug-unplug cycles from a well-designed outlet (Hubbel, Bryant, etc.) whereas a breaker may only get 50-100. While an outlet cost may be more than a breaker, degrading the safety of a breaker should never be done.

Note that for the best answer you should probably consult a qualified electrician. That is, not me.

A possible solution, again I'm not an electrician, would be to install an on/off switch for your 14-50 outlet.
 
Are breakers intended to be switched that frequently? I would worry that this was moving too much cycling of the receptacle to too much cycling of the breaker. But I have no clue which is better.
Good point. I rarely charge my car at home so this option works best for me. But I agree, if the breaker needs to be switched on/off frequently it may not be the best option.
 

RayK

Safety Score 90 (Was 96!)
Apr 5, 2016
3,147
3,285
San Jose, CA
@M3BlueGeorgia If you are disagreeing with my suggestion to use an on/off switch, or perhaps you think a socket has a higher cycle count, then maybe I should clarify some....

I'm not talking about a simple wall switch that controls a ceiling light; it's something along the lines like this:


Yes, it's expensive at around $160. But if the OP is REALLY concerned about the consumption of idle power and doesn't want to unplug-plug the mobile connector, then this is one solution (IMO). However, I should say that a cost-analysis should be probably be done to see what the cost in electricity is for the idle current of the mobile connector, versus the cost of a switch like this. And for what one might expect if you simply unplug the mobile connector when it's not being used.

The following assumptions are; idle power for mobile connector: 10W; idle power time: 16hrs; cost of electricity: $0.25/kWh (estimated avg. for CA rates); no change in the cost of electricity over the life of these calculations (yeah, that's a fantasy):

ref: Electricity usage of an Incandescent Light Bulb - Energy Use Calculator

From plugging those numbers into the calculator referenced above, let's say that it costs $0.04 per day to keep the mobile connector powered up. That's $14.60 a year in electricity. After 11 years that amounts to $160.60, which is just about the cost of one of those Bryant 60A switches. I don't know how many on/off cycles a switch like this can endure so that needs to be taken into consideration. But when was the last time a light switch in your house failed? Remember, using an on/off switch for the 14-50 socket is only going to switch instantaneous power to an idle mobile connector and not 32A (the maximum it can provide). That's 10W of power. I'd posit that most people are switching more that than that for their household lights; even those of us who have converted to LEDs. The main reason I've selected a 60A switch is that it has more than enough capacity to sustain a continuous 32A but I supposed that a lower capacity switch would cost a bit less and therefore extend the amount of time for this return-on-investment calculation.

Looking at the other side of the equation, let's figure out what it would cost if one unplugs the mobile connector when it's not being used until the socket fails. I've seen estimates in forums that good sockets like the Hubbell or Bryant can endure 500 cycles. I can't find any published spec from Hubbell so I'll have to guess and say after 3000 cycles the socket will be toast (and hopefully not the house it's connected to). A worst case situation of charging the car every day is 365 cycles in a year. So after a bit more than 8 years it would be time to replace a $150 socket. Changing to charging the car every other day and that extends the life of the socket to 16 1/2 years.

TL;DR:
  • Cost to keep the mobile connector plugged in: $0.04/day or less than $15/yr (CA electricity rates)
  • Material cost of the on/off switch and a good NEMA 14-50 outlet is about the same: $150-$160; installation costs ignored
  • It would take 11 years to recoup the cost of an on/off switch but you'd be (very slightly) lowering your energy consumption while doing so
  • Using an on/off switch adds another point of failure in the system
  • It would take 8 years to recoup the cost of a socket if you unplug every single day, with the added danger of possibly having the socket catch fire
  • Lifespan of the socket will be extended if charging once every two days
 

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