Cybertruck lead engineer warns against using NACS extension cords at Superchargers

[Old Spice]

Per Wes Morrill:

"Would recommend AGAINST using an extension cord on a supercharger (or any DC charging station with a liquid cooled cable). Have seen multiple instances of the cable overheated and shorting DC +/-

There's a temperature measurement in the handle and the supercharger derates based on that temperature. With the extension cable that safety goes away. On top of adding an additional junction which generates heat making matters worse."

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[Gaximus]

I like that he explains the reasoning behind it.

I bet they could update the Supercharger to detect this at some point, just testing the resistance of the wire, and it its to great, limit charging or disable completely.

 

[SSonnentag]

I like that he explains the reasoning behind it.

I bet they could update the Supercharger to detect this at some point, just testing the resistance of the wire, and it its to great, limit charging or disable completely.

Great idea. It would probably require hardware modifications to every charging station, but it might prevent a bunch of short and potential fires.

I favor the test and disable option.

 

[Chris Pierce]

I bought an extension cord. Multiple warnings against using at a L3 charger. VERY useful to me at L2 chargers when I couldn't park close enough, and at homes to reach the dryer outlet when road tripping and staying at relatives or an AirB&B.

 

[REM]

Unauthorized high voltage electrical devices. What could possibly go wrong.

Anyone caught using third party devices like this should be banned for life from the supercharging network.

 

[SSonnentag]

Unauthorized high voltage electrical devices. What could possibly go wrong.

Anyone caught using third party devices like this should be banned for life from the supercharging network.

What ever happened to Rick Astley anyway? I really liked some of his music.

 

[jasonclu]

Well they need to make cables longer then. I’m always having trouble hooking up my CT at the superchargers. Either hurry up with the app summon so I can back up the truck with the app, or allow us more room to back up in to the parking spot

 

[CyberGus]

I favor the test and disable option.

Sure, BUT such measures tend to have a margin-of-error that will cause some unsuspecting innocents to be denied charging.

The vendors of NACS extensions warn that it's strictly for L2 charging and NOT SuperCharging.

Maybe these cords should have integral current or heat safety cutoffs. Tesla sued EVject, maybe they need to sue these vendors also if this is really becoming a problem.

 

[Sjohnson20]

I bought an extension cord. Multiple warnings against using at a L3 charger. VERY useful to me at L2 chargers when I couldn't park close enough, and at homes to reach the dryer outlet when road tripping and staying at relatives or an AirB&B.

yeah having the extension cord is great for L2

 

[CyberGus]

Well they need to make cables longer then. I’m always having trouble hooking up my CT at the superchargers. Either hurry up with the app summon so I can back up the truck with the app, or allow us more room to back up in to the parking spot

I need to back in really close but I've always been able to reach the charge port.

 

[CyberGus]

What ever happened to Rick Astley anyway?

He let me down.

 

[REM]

What ever happened to Rick Astley anyway? I really liked some of his music.

I guess he gave up on us ?

 

[davooodave]

Just to confirm, I’ve been using a heavy duty 15 amp 3 pronged extension cord for level 1 charging when traveling. Is this a better or safer option than that? This extension would also allow me to reach more dryer outlets for faster changing when traveling.

 

[Jhodgesatmb]

Per Wes Morrill:

"Would recommend AGAINST using an extension cord on a supercharger (or any DC charging station with a liquid cooled cable). Have seen multiple instances of the cable overheated and shorting DC +/-

There's a temperature measurement in the handle and the supercharger derates based on that temperature. With the extension cable that safety goes away. On top of adding an additional junction which generates heat making matters worse."

I am assuming that is this NACS extension cord is intended for people with boats and trailers, since otherwise you can just back up to the charger cable. One would think that the designer would think about the cooling requirements before going to the trouble of manufacturing such a cable. I doubt they assume any liability but they should.

 

[ÆCIII]

It might be possible, albeit much more expensive, to make an extension cable that also has it's own cooling or prevention of heat buildup, via simply larger conductors/cable, or with some kind of separate cooling loop of it's own with connections and a pump through a radiator box of it's own. Of course this is 'reaching' (pun fits - so why not), but there would need to be a solution that works independently or transparent because neither the charger nor the Tesla onboard software is going to know when someone is using an extension cable.

Meanwhile, I would not buy any extension cable which did not specifically guarantee safety and ability to handle the voltage and current without thermal buildup.

It says "UL Certified" so if they are genuine, it should mean that United Laboratories would've sent someone out at a supercharger and tested this extension cable under all the maximum voltages and currents that would be experienced, or they would've tested it with a Supercharger in their lab. However today I'm hesitant to trust any kind of agency 'certification label' alone. I would want to also see videos of UL performing said tests, and if the performance was proven safe that way only then I'd think about buying one.

Time will tell, but if Tesla finds that certification isn't adequate for true safety, they should sue the company just like they sued EV Eject, until said cable would be made to operate safely if it isn't already. These type of accessories implicate Safety at Tesla Superchargers, which is why Tesla engineers weighed in with precautions in the first place. We likely will be hearing much more about this.

- ÆCIII

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