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Extension cord for charging at 110V?
- Thread starter surfrasch
- Start date
eprosenx
Active Member
Ok, now you are going to have to explain what you mean since you have piqued my interest! ;-)
Are you referring to cutting the neutral pin off the 14-50 adapter (since it is never used) which let's you plug that into a 14-30? (of course you then have to be responsible for setting the amperage manually down to 24 amps any time you use it in a 14-30)
The Amazon adapter I linked to that let's you use the 5-20 Tesla Adapter in a 5-15 receptacle has similar safety concerns if used improperly as well (it is actually kind of worse since it could let you draw 16a continuous on a receptacle only intended for 12a continuous but would not blow the breaker since it may be 20a).
I did go find the reference online to someone else's teardown of a 15a 5-15 and a 20a 5-20 120v receptacle. You can see that the guts are identical and according to the manufacturer the spring tension is even the same. So this is why I am willing to use that Amazon adapter with the Tesla 5-20 adapter in certain situations. Though just because one manufacturer makes the same part for both receptacle types does not mean that is universal.
5-15R vs. 5-20R - Specifically, What's the DIfference? - Page 2
Generally, but I'll bet this is talking about the other way, which is more common. Since there were about 2 years where Tesla didn't sell any form of 30A UMC adapters, lots of places were making pigtails to adapt everything to a 14-50 outlet (and are still selling those). Once Tesla did finally offer the 14-30, people bought it, but then had all these pigtails that converted 30A outlet types to 14-50. For much better safety, it makes sense to cut the neutral pin off, so you can plug your official 14-30 Tesla plug into those, so it will set the current properly and automatically, rather than you having to remember to do it in the car.
Cutting the pin off a Tesla 14-50 isn't a very good idea, since that is just allowing you to overdraw a circuit.
WileyTheMan
Peanut Gallery Member
Boy, I can't stress how important it is to make sure you don't charge off an extension cord on a regular basis. I did that and ended up frying the electrical outlet (after nine months, mind you). I was informed later that one of the reasons Tesla doesn't recommend extension cords is because it bypasses certain thermal protection safety features of the mobile charger.
Snow Drift
[Off-Road Assist] Activated
I have this one and it has worked great daily since December.
https://www.amazon.com/gp/aw/d/B07GQ8RPGF?psc=1&ref=ppx_pop_mob_b_asin_title
15-ft 12/3 Heavy Duty Lighted SJTW Indoor/Outdoor UL Listed Extension Cord by Watt's Wire - Yellow 15' 12-Gauge Grounded 15-Amp Three-Prong Power-Cord (15 foot 12-Awg)
https://www.amazon.com/gp/aw/d/B07GQ8RPGF?psc=1&ref=ppx_pop_mob_b_asin_title
15-ft 12/3 Heavy Duty Lighted SJTW Indoor/Outdoor UL Listed Extension Cord by Watt's Wire - Yellow 15' 12-Gauge Grounded 15-Amp Three-Prong Power-Cord (15 foot 12-Awg)
I went with this one. I think it's wise to go with the largest gauge to cover you and reduce heat loss...and this will cover me for 15A or 20A situations, and isn't too long as to increase resistance unnecessarily. My thoughts are this stuff isn't meant to go cheap on - it's worth a bit more money for safety and peace of mind.
https://www.amazon.com/gp/product/B078KFMGP4/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B078KFMGP4/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1
Good call, most of the 12G AZ cords fail and melt when used on an EVSE. Keep an eye on the terminations over time and the color of the prongs.
At what voltage does the car stop charging. I ran into this problem at a cottage and the car would not charge. If I get a 10 or 12 gauge, what is the limit of how long the chord can be recognizing the longer the chord, the more voltage drop.
Mobile chargers Gen 2 and Gen 1 have thermal resistors installed inside the outlet. It serves two purposes at once: limit maximum amperage for the outlet (different resistors in Nema 14-50, etc.) and monitors the temperature so it can cut out the current in case of overheating and fire. With extenders or third-party adapters you'll have two possible points for overheating and spontaneous combustion - extender-to-wall outlet and extender-to-charger. Second point is monitored by a thermal resistor, the first one is not and can (and will) burn in case of over-current.
I bought a Camco TT-30 extension at an RV shop, and built a charging kit around it. It is pretty heavy duty with 10 ga wire and insulation rated to 600V. There are lots of off the shelf adapters with 5-15P and 5-20P to TT-30 and back available in the RV community. Combine with the Tesla 5-15 and 5-20 UMC adapters, and the evseadapters TT-30 adapter for a solution at each amperage level. There are also TT-30 "repair parts" available, in particular receptacles on pigtails, for making homemade custom adapters with the plug of your choice.
For example I made an adapter with a 14-30/50 plug with neutral blade omitted so it will plug into either receptacle. Since there is TT-30R on the other end, and the TT-30 UMC adapter is eventually used, charging will always be safely done at 24 amps max.
While it doesn't support the full 32 amps of the gen 2 UMC, or 40 amps of the gen 1 UMC (I also have one of those), 24 amps max is fine for the rare times I've actually used it. Cost, size, and weight is also much less that a 14-30 or 14-50 based kit.
For example I made an adapter with a 14-30/50 plug with neutral blade omitted so it will plug into either receptacle. Since there is TT-30R on the other end, and the TT-30 UMC adapter is eventually used, charging will always be safely done at 24 amps max.
While it doesn't support the full 32 amps of the gen 2 UMC, or 40 amps of the gen 1 UMC (I also have one of those), 24 amps max is fine for the rare times I've actually used it. Cost, size, and weight is also much less that a 14-30 or 14-50 based kit.
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CheapBastid
Member
Although I'm told "curiosity killed the cat" I just tried to charge my M3 LR (for 3 minutes) with this cord and it worked fine. I figured I would only use for emergencies although I don't know what that means. We have a two car garage but my wife's Tesla and my Fiat 124 Spider fill that up.
I thought I'd use it on nights that go well below freezing but not sure how well I'd sleep wondering if the house was going to burn down. I guess I could stick the Spider outside and put a cover on it...decisions decisions. The outlet in the garage is about 4' too far.
I thought I'd use it on nights that go well below freezing but not sure how well I'd sleep wondering if the house was going to burn down. I guess I could stick the Spider outside and put a cover on it...decisions decisions. The outlet in the garage is about 4' too far.
16 ga is too thin. Go 12 ga for a few dollars more.
10 is fine too. The TT-30 extension I mentioned a few posts upthread has 10 ga conductors and is good on a 30 amp circuit (24 continuous). Probably heavier than what you are looking for though.
The problem with thin extension cords is that they are designed for general use. An EV charging takes maximum current for long periods of time. That is what is causing the warming of the wire. If you are using a heavy duty cord, and it runs cool, you are probably going to get by in a pinch, but the inexpensive thin wires are not only slowing things down, but they are a danger as well.
Best option for charging at 120V is to use the charging cable that comes with every Tesla. Use the Adaptor you can order from Tesla that will allow it to plug into a 120V socket. Should be good to go. I cringe every time I see an extension cord, snaking it'w way out of a motel room, leading to a parked EV.
Best option for charging at 120V is to use the charging cable that comes with every Tesla. Use the Adaptor you can order from Tesla that will allow it to plug into a 120V socket. Should be good to go. I cringe every time I see an extension cord, snaking it'w way out of a motel room, leading to a parked EV.
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