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charging from 120/240 outlets

Discussion in 'Model 3: Battery & Charging' started by calitexican, Jul 31, 2018.

  1. calitexican

    calitexican Member

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    Hi all - we're currently charging the slow way on 110 but our garage also has a 120/240 outlet that was supposedly included specifically for electric vehicle charging. It doesn't seem to match up to any adapter that would allow charging at 240 however.

    When I searched online, I found the matching adapter labeled as 6-20, the specs matched up, i thought "great!" and ordered it - well the prongs are reversed. Tesla advises the 5-20 would match up, but that only allows charging at 120 if I'm not mistaken. Any advice?

    Here's a photo of the outlet.

    20180724_125901 plug.jpg
     
  2. P85_DA

    P85_DA Supporting Member

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  3. Derek Kessler

    Derek Kessler Member

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    That's a NEMA 5-20, which is 120V at 16/20A (and compatible with a standard household outlet).

    If it's supposedly wired for 240V, then you need to swap out to a different plug. It'd check it against the breaker box, but I'm not optimistic that you have more than a 20A breaker there — especially if the outlet is on a shared circuit.
     
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  4. Kermee

    Kermee It's Not Easy Being Green

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    Yup. It's a NEMA 5-20 plug and is typically 120V rated for 20A (16A). From anecdotal posts I've seen previously, it's actually a huge step up from the standard 5-15 plug 15A (12A). The 4A difference doesn't seem like much, but from what I understand, there's a fixed amount of efficiency "loss" so the 4A difference is virtually all going into the battery.
     
  5. FourOhFour

    FourOhFour HTTP Error

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    #5 FourOhFour, Jul 31, 2018
    Last edited: Jul 31, 2018
    If you have reason to believe it is "120/240", I suppose it is possible the second hot was pulled but is just capped in the box and a 5-20 was installed, perhaps for compatibility with a plugin hybrid's bundled EVSE. Find the circuit breaker for the outlet. If it is two breakers connected by a bar, then either that outlet is miswired as 240 (possible, some idiots do this because the gen 2 volt's evse apparently works at 240 even though it's only rated for 120), it's sharing a neutral with another circuit, or it's a 240 circuit just waiting for an outlet swap.

    If it is a single breaker, then it is a 120v circuit. Assuming you have space in the panel and enough amps available, and nothing else is on that circuit, an electrician should be able to swap the breaker and outlet to make it a 240v 20a circuit without much difficulty.

    Edit to add: If it is wired to be 120/240, I'm not sure what it could have been intended to be... 14-20 exists but isn't particularly useful. If it's a higher amp circuit, the 14-30 and 14-50 aren't supposed to be used in a single gang box. L14-30 or L14-50 might fit, I suppose. I'm putting my money on it is what it appears to be: a 20-amp 120v circuit.
     
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  6. TexasEV

    TexasEV Well-Known Member

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    If you can make it a 240V 20A circuit, change the outlet to a 6-20 and you can use the adapter you bought. You'll get twice the rate of using the 5-20 adapter and outlet-- about 12 miles/hr for the Model 3.

    Or better yet, if your panel can support it, just forget what you have and get a NEMA 14-50 outlet installed. It's not that expensive if your panel is in your garage. That way you can charge at 30 miles/hr like the rest of us, and always have a full (90%) charge in the morning.
     
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  7. calitexican

    calitexican Member

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    thanks so much everyone!

    it's labeled on the breaker box as 120/240v but on a single breaker (#19 in image below). i was wondering if it would support changing the outlet to 6-20 configuration.

    the panel is in the garage and there is another outlet nearby so i'm assuming we could have a 14-50 installed but 6-20 would work fine for us if that capability is already here.

    20180731_205423.jpg
     
  8. calitexican

    calitexican Member

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    I don't see how to give you all props for your answers but I found them all helpful & informative =)
     
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  9. brkaus

    brkaus Active Member

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    If the circuit is dedicated (the absolutely only one on that breaker), it could easily be changed to a 6-20 outlet. As others have pointed out, you have a 5-20 (120v).

    To convert, the breaker would have to be swapped out, wired slightly different, and a new outlet installed.

    Btw - the 120/240 on the breaker means it is rated for either one, but it is currently wired as 120.
     
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  10. calitexican

    calitexican Member

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    ok cool, thanks! very helpful.
     
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  11. eprosenx

    eprosenx Member

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    Others have given great advice here, but I will just pile on:

    I have a receptacle like that in my garage. Mine was intended for a freezer which is common. (putting it on its own circuit I think works (worked?) around the GFCI requirement in garages)

    Swapping it to a 240v outlet so you can use it with the adapter you got is a trivial operation assuming you can 100% ensure there are no other receptacles daisy chained off that circuit. You clearly have available breaker positions for a double wide breaker based on the picture you posted. Worst case you would need to extend the wire/wires in the breaker panel in order to reach a new breaker position. This would probably triple your charge speed.

    As others have mentioned, depending on your overall load calculations for the house you could just do a NEMA 14-50 on a 50a branch circuit or even a Wall Connector on some amperage circuit (a 60a circuit will let you max the charging speed of the M3 long range - but the Wall Connector is rated up to a 100a circuit if you wanted to future proof or needed to charge Model S or Model X vehicles with the faster chargers). If the panel is close to where you want the plug/charger the parts cost is trivial (say $100 if right below your panel).
     
  12. calitexican

    calitexican Member

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    That helps a lot, thanks! We are getting electrician quotes...I was waiting for this car for so long and then it felt like it arrived suddenly, still trying to catch up.
     
  13. Dana1

    Dana1 Member

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    Have you gotten quotes from Tesla’s electricians? They did an amazing job with mine...I posted photos on another thread.
     
  14. calitexican

    calitexican Member

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    i will check out the photos - thanks! i thought initially we'd be able to use the existing outlet so i didn't get any quotes...just got one from a local electrician ~$300 ...he said we'd be better off just putting in a new outlet.

    there's also a program with access to level 2 chargers across the city for ~$5/month, my husband wants to try that for a few months first as there's one at his office garage & then decide on the install.

    so after everyone's generous advice we're going to wait and see....bookmarking this discussion for later. thanks again, everyone!
     
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  15. brkaus

    brkaus Active Member

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    You can still use the existing outlet w/o modification. It will add ~5+ miles per hour of charging if you buy the 5-20 adaptor from Tesla. I'd spend the $35 on that adaptor. It will boost the current from 12a to 16a (33%).

    The Austin Energy $5/mo works pretty well, but I would only do it if you know you would stay somewhere with charging for long periods of time (you mentioned work).

    Yes, if you were going to go with a 14-50 (or the Tesla WC), better to just add another outlet.
     
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