Is it ok to leave charger plugged into outlet.

Is it ok to leave charger plugged into outlet.

Just wondering if anyone has heard of any negatives to leaving the charger plugged into the 240 watt outlet all of the time. When I unplug the charger from my car, I just hang it on a water hose holder, but the charger is still plugged into the wall. Is this bad for the longterm life of the charger?

Thomas N. | 19 september 2013

It most likely doesn't trip on unless something is plugged in. Kind of like a USB port hanging off your computer with nothing plugged into it.

Of course there are some active electronics that may be affected. It's a good question, but I imagine the wear and tear from plugging and unplugging it everyday would be worse for it.

Mireille '&... | 19 september 2013

Have kept ours plugged in for 8+ months; no problems.

hfcolvin | 19 september 2013

6+ months. I unplug it to take it on road trips. Outdoor outlet BTW.

Earl and Nagin ... | 19 september 2013

Its actually best to leave it plugged in all of time. Those 240 volt outlets aren't designed for many plug/unplug cycles like 120 volt outlets are.
The only issue might be phantom leakage. I don't know how much power the charging cable draws when in is idle.

hamer | 19 september 2013

I don't think we can really guess the answer to that. Most inexpensive electronic power supplies / chargers like those for phones, etc., continue to use power, even when the device is unplugged, but it isn't very much. On the other hand, I would not be surprised to see that an expensive power supply / charging cord like the UMC, designed by a premier company like Tesla, was an exception to the rule, with enough intelligence built in to know whether it was connected or not, and to behave intelligently.

We need to either get word from Tesla, from someone who actually knows the answer, or someone needs to measure power drawn with the UMC plugged in and not plugged in to see how it is doing. I do not have the equipment to do that.

jbunn | 19 september 2013

No, we don't need to get word from Tesla. Just keep it plugged in.

One of the members here had the equipment and already ran the test. (Volkerize if you like) The adapter draws little to no current. Just enough to keep the tiny green light lit. Compared to the power the car draws, it's not noticeable.

The car is intended to be fun to drive and easy to operate. No reason to make this any harder than it is. You'll do more damage to the connectors plugging and unplugging constantly.

PaceyWhitter | 19 september 2013

As jbunn says, the power used is minute, and as Earl says, unplugging wears out the NEMA 15-50 outlet (which will then eventually have to be replaced) while they are not that expesive, they are much more expensive than the minor amount of power used, and if you have an electrcian do the replacing the cost goes much higher. Otherwise you have to deal with the rather thick wires yourself.

In short, keep it plugged in.

amish.bhatia | 19 september 2013

Does that mean I should get a spare mobile connector? I was going to be charging at the office (Just got my plug installed!) and also at home (still going to get a plug installed there). people are saying not to plug it in or take it out too much, but I imagine thats what I would be doing. worth 650 for a spare mobile connector?

AlMc | 19 september 2013

amish: I did go with a spare mobile connector that stays with the car. It was extra $ but alleviates the plug/unplug question and I know I have a connector with me wherever the car goes.

mclary | 19 september 2013

Yes. Leave it plugged in!

It amazes me the questions people post on this forum. Drive the car and enjoying it! Stop worrying about the little things and don't blame Tesla!

mclary | 19 september 2013

Oh and the charger is built into the car. The cord is just a cord!

AlMc | 19 september 2013

@mclary: Who was 'blaming Tesla' in this thread? There are many threads where people blame TM for everything but this was not one of them. Honest question/civil discussion/no blame game

mclary | 19 september 2013

I was speaking in general about blaming Tesla.

JPPTM | 19 september 2013

I leave it plugged in. Note that I bought an extra NEMA 14-50 adapter as I was told that the 'standard' NEMA 14-50 receptacle is not designed for lots of unplug-plug cycles and can fail. Thus I unplug-plug as needed from the adapter. FWIW, then if something fails it might be more expensive (UMC and/or adapter) than the $10-15 NEMA receptacle (labor to replace not included). I however wanted to avoid any thermal issues and meltdown.

Thomas N. | 19 september 2013

Strange comment Mclary. You can speak in general about blaming Tesla but maybe it would be more productive to speak about it in a thread where they are actually blaming Tesla.

I know a lot about the Model S and I learned something in this thread. I didn't know that a minute amount of power was used even when the Tesla was not plugged in so for that alone I am pleased the OP asked the question.

jbunn | 19 september 2013


Before you get a second mobile charger, make sure you need one at work. Are you just getting a socket at work, will you have a j1772 charger? If you are going to have a charger at work, you don't need to bring your mobile charger. Also, if you take your mobile charger to work, you probably are not going to leave it outside when the car isn't there.

So if you just have a socket at home and a socket at work, you will be the exception. Someone who plugs and unplugs every day. That's fine if you need to.

rodhoffman | 19 september 2013

I have a second mobile charger and have never used it but it is a "just in case" and I have not strayed more than 200 miles from home in the Colorado mountains.

I leave mine plugged in and have for 6 months - no issues!

Rod in Evergreen, CO

mallynb | 19 september 2013

Our Model S is programmed to charge after midnight. Plugging it in before midnight, when it needs charging, is the only thing necessary for us to remember. | 19 september 2013

No problem. Leave it plugged in.

PaceyWhitter | 19 september 2013


You are not going to need to replace worn 15-50 outlets that often. I doubt that it would save you 650 over the course of its lifetime.

mike | 21 september 2013

BTW - a couple folks refer to a "charger" or "mobile charger." This is incorrect. It is a "connector" not a "charger." The charger is in the car.

CheckeredFlag | 21 september 2013

I actually called Tesla about this when I first brought the car home. I thought it might be a safety hazard. Like above responses, Tesla indicated negligible power usage when not connected to car... No need to unplug from outlet.

burky33 | 26 september 2013

Thanks everyone...

sonofomar | 14 december 2014

I'd like to reopen this question: can/should we leave the connector plugged in the NEMA 14-50 wall outlet when not charging? Page 3 of the Mobile Connector Owners Manual states in Step 3 of the "Unplugging In" section: "Unplug the Mobile Connector from the power outlet and store it in an appropriate location."
And on page 7 the warranty terms cite "failure to follow instructions" as a reason to void the warranty. We charge every night with the UMC, and it is convenient to leave it plugged in all the time except when taking a road trip. I plan to continue doing so regardless of the manual. A post above suggested a Tesla rep approved leaving it plugged in and implied the extra power consumed was negligible. Has anyone actually measured the power consumed by the UMC when not charging? Anyone have any reason to be concerned about long term effects?

cantcurecancer | 14 december 2014

Look. Any engineer worth their salt is going to make their product idiot proof. They are not going to make it easy for a customer to damage their product. That's design 101. They've made the right way to use the thing, the easiest way to use the thing. That's why, for example, if you just go to plug it in, it will charge to 90% because that is better for the have to go out of your way to charge to 100%. Just plug the thing in and forget about it.

It's the engineers job to design their product in such a way that it's impossible for a customer to accidentally destroy a $100,000 car.

Captain_Zap | 14 december 2014


I think those instructions are to keep it from getting ran over.
The UMC is the mobile connector intended for use on the road and at public charging stations.

@cantcure +1