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Discussion Starter · #1 ·
I know enough about electricity to know the longer a cord is the more voltage drop there will be and this hurts efficiency and at some point the drop would be too low for a charger to operate.

I'm planning to get a charger installed in my condo parking space, but in the meantime my parking space is about 150' from where I could plug it in. I'm trying to understand if it's foolish or dangerous to buy a 100' extension cord and a 50' extension cord and plug in via the included charger. The fact that 110V heavy duty extension cords more than 100' don't seem to exist seems like it might be a red flag, and in any case I'm not sure if there are considerations for using them with an EV charger.

I don't drive a ton of miles each day, so I sort of figure round the clock 110V charging should be good enough for my needs most of the time, and if I'm taking a long trip or end up getting quite low I could visit a charging station to top off the tank.

Anyone tried a cord this long?

Relatedly I also have several 220V unused outlets (e.g. unused dryer plug) but I find that extension cords for 220V NEMA plugs are even more limited (50' seems to be the max and they are expensive) so I am really doubtful it'd be a good idea to chain 3 of them together. This seems weird as I would have thought overall it'd be more efficient to run electricity over a long distance via a higher voltage but maybe there are some considerations here. The 220V cords (50A) are also very expensive. I realize my dryer plug is likely not 50A but I think I read there are ways you can tell the truck to charge at a lower amperage.

Hopefully I'm getting the truck Friday & trying to not be completely unprepared when it shows up. Also even once I have a charger installed, I figured it might be worth carrying a long extension cord in the truck for emergency charging when I can find a plug but it's not that close to where I could park the truck.
 

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It's a math problem. I'm not an electrician but I do know that since 2012 the National Electrical Code has varied on how to calculate this. But for the most part I think the industry agrees that an 80% factor is acceptable for a continuous load. You'll need to increase the wire size to a match the voltage drop and you might need to adjust the amperage draw from the vehicle. Keep in mind it's a sustained load. It's not like starting up a table saw or compressor that drops off after 5 seconds. In order to begin to find a solution - you'd first need to know the rating of the source outlet and what it can provide in sustained load. Assuming a 120v - 15 amp circuit with nothing else loaded it can safely provide 12 amps. (The max continuous load could be .8 x 15 = 12 amps.) Now you just need to size the wire to carry that 12 amps the distance. According to the calculator linked here (Circuit Distance Calculator) you'd need 4 AWG CU wire (at 75 degrees) to travel 161 feet.
 

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This is question has multiple challenges:
First being the length of the extension cord, the heat generated and the power you can actually draw from it. There is a reason most EV chargers are short cables (25-30 feet at max)
Second is will the vehicle see this as a problem and just not charge.

I would also talk with the condo management team and see if they are working on EV charging spots. Several are because they know it is the future and don't want every tenent installing their own, that would be a mess.
 

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Discussion Starter · #7 ·
Definitely planning to trench and bury a conduit for 220V charging long term. It's taking a while working with the HOA / contractor to get it done so I'm seeing if I have any options shorter term. Good news the truck is here quite a bit sooner than expected but I guess I should have been working more diligently to get a charger installed.

Side issue @lefkonj we all have assigned parking in the condo (and I'm helping the HOA board come up with a charger strategy) but given the incentives from the utility in California to charge behind the meter it sort of seems like the most practical option is every unit that wants EV charging does install their own. SCE has a program to install public chargers but then you end up having to dedicate room for shared parking, swipe a card from a commercial charger and lose the benefits (hopefully) of V2H V2G longer term. The program also takes 1+ years & would need group buy in from the HOA. Right to individual chargers is provided by CA statute. It does seem like a mess, but seems to be the least messy option.

Interesting to know 1-1.5 mph is all folks are getting on 110. This still works out to 24-36 miles per day which might be good enough for my usage... but I don't want to start a fire obviously or cause some other issue.

Seems some folks are using long extension cords and it's working and clearly there are some concerns about it.


@sciencegeek - did you happen to notice if your extension cord was a "heavy duty" cord rated for 15 amps? I notice the "light duty" or "medium duty" extension cords which are cheaper probably wouldn't work.
 

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Keep in mind that the "rated for 15amps" only applies to the length of that cord. Adding them together, you need to adjust. A 10awg 100 ft cord is good for 15amps but if you add another 50ft for a total of 150ft, you need to have all the cords be an 8awg.
 

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14 AWG, 20 amps.

On another note, the L1 charging loss is already 20-25%, and even if the charging unit worked with the extension cords your loss would be higher and I doubt you'd even get 0.5 miles / hr. Frankly, I'd abandon the idea, be ok with the hassle of charging elsewhere for a few weeks, and put my energy into getting that L2 capability asap.
 

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No way you can run a 220 extension cord close to that far.

on 110 I regularly (as in most weekends Dec-May) charge my Tesla at my cabin off a 25’ 8-gauge extension cord. It does fine. I’ve never had a problem or noticed it being hot. 150’ is very long. If you do go down this road would look into a custom made 150’ instead of piecing together 50’ x3.

And I’ll add charging off 110 sucks, if I only had 110 I would not own an EV. And the R1T has almost double the Wh/m as my Tesla and there for roughly double the charge time.
 

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Discussion Starter · #11 ·
Rethinking this a bit, I'm curious why you say "No way you can run a 220 extension cord close to that far" @ColeAK . One way I could think of it might work is with a 50A 6 gauge 240 V cable. I am kind of curious how fat a cable must be installed in the ground for the charger to work (or what size cable runs to both me and my neighbor's unit (same feed from the utility) given we both have 200A service and it runs more than 150' from the transformer.
 

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Discussion Starter · #12 ·
Not really suggesting that I'd run 150' 6 gauge extension cord, as I think that would cost $600+ but I am starting to look for some temporary solutions until I can get my charger installed. Some closer research on plug share indicates there isn't a single non-Tesla public charger in my town. This will be exciting I guess.
 

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Discussion Starter · #13 ·
Related question: I think I had read it's possible to configure the truck or the charger to charge at a lower amperage if you know the plug you are connected to can't provide 48 amps. Not sure if this was for the home charger or the one that comes with the truck or it's a setting on the truck itself. Or maybe I had misremembered this.
 

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Related question: I think I had read it's possible to configure the truck or the charger to charge at a lower amperage if you know the plug you are connected to can't provide 48 amps. Not sure if this was for the home charger or the one that comes with the truck or it's a setting on the truck itself. Or maybe I had misremembered this.
Yes, you can limit charging current in the center screen.
 

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If you have canopies for covered parking, you could avoid the trenching and run the cables (MC or possibly SER) along the ceiling for both short term and long term solutions.

On the side, what was the HOA thinking of installing? Any consideration to networked Dual 80 Amp EVSE? Would think that something like that with a key card could be billed to the owners who use them while being a capital benefit for everyone to justify the initial investment outlay…. Just a thought.

Something like these: [image]
 

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Rethinking this a bit, I'm curious why you say "No way you can run a 220 extension cord close to that far" @ColeAK . One way I could think of it might work is with a 50A 6 gauge 240 V cable. I am kind of curious how fat a cable must be installed in the ground for the charger to work (or what size cable runs to both me and my neighbor's unit (same feed from the utility) given we both have 200A service and it runs more than 150' from the transformer.
50’ is the longest 220 extension cord I have ever heard of. I had a 20’ 30a when we had our airstream. Disclaimer, one of my bachelors is in engineering but I’ve never worked as an engineer and I’m an amateur electrician, carpenter, builder,….

Also in many municipalities there are pretty heavy restrictions on 220 extension cords. If you’re even thinking about going down this road you should talk to a local electrician they will know the limitations better and also be the one to possibly build you said 150 foot extension cord.
 

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50’ is the longest 220 extension cord I have ever heard of. I had a 20’ 30a when we had our airstream. Disclaimer, one of my bachelors is in engineering but I’ve never worked as an engineer and I’m an amateur electrician, carpenter, builder,….

Also in many municipalities there are pretty heavy restrictions on 220 extension cords. If you’re even thinking about going down this road you should talk to a local electrician they will know the limitations better and also be the one to possibly build you said 150 foot extension cord.
They do exist. Here’s one: Heavy-duty NEMA 14-50 extension cord for electric vehicle only, 100 ft. – EVSE Adapters

That said, I wouldn’t use one, personally.
 
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