extend UMC cable length

[Federico]

Many people will not recommend to use an extension cable (Tesla included), but I will give you my setup.

I do have a Model 3 SR+ which can only charge up to 32A, the mobile connector gen2 (included with every Model 3 purchase) can only provide a maximum of 32A. Since my apartment is on the second floor I installed a 14-50R 5ft away from the main electrical panel (I used 6AWG for that), then I bought a 75' SJOOW 8AWG cable plus 2 Camco 14-50 adapters to make my own extension cable. I have been using this without any issue for the last couple of months and the voltage drop have been 2 volts (from 241 to 239v), still 32A and getting 32mph and it doesn't even get warm.

My advise? you can use an extension,, the voltage drop is not going to be big, besides everytime you use like a chargepoint station, they only provide 208V or less (Commercial electricity is 208v vs 240v at home). After all, a lot of people install a 14-50R 40~100 ft away from the main electrical panel, so the voltage drop is almost the same that someone using an extension cord from a 14-50 receptacle that is next to the main panel.

Just my 2 watts...

 

[darth_vad3r]

I thought I remembered someone posting about a problem recently with their QCP extended UMC cable but I couldn’t find it earlier with search to post here ... then the OP @Machostallion posted an update a few hours ago and the thread got bumped

Problem: Problem with UMC lengthened by Quickchargepower
“the splice nearest the Tesla brick is uncomfortably hot. Also, I have noticed that the charge rate constantly goes up and down between 29 mi/hr and 14 mi/hr. The amps also get cut in half from 32 to 16.”

I took delivery of my LR AWD in March. The logistics of charging at both of my houses require a longer umc cable. Both locations have a 14-50 on a 50 amp breaker. Initially I was using a extremely heavy duty 25' RV extension cable but after browsing through these forums I saw some recommendations for Quickchargepower and their service of extending the umc cable which keeps the safety measures of the umc in tact.

I purchased an additional umc and sent it off to Quickchargepower and got it back quickly with an additional 20' spliced in. The cable worked great up until the last week or so. About a week ago I noticed that the two covered spiced areas of the cable were noticibly warmer than the rest of the cable while charging. Now the splice nearest the Tesla brick is uncomfortably hot. Also, I have noticed that the charge rate constantly goes up and down between 29 mi/hr and 14 mi/hr. The amps also get cut in half from 32 to 16.

I tested my original unaltered umc and a heavy duty RV extension cord and it still charges normally with no drops in charge rate and nothing gets abnormally warm.

At this point I'm afraid to keep using the lengthened cable from Quickchargpower regardless of the safety measures built in.

Has anyone else had this problem with any cable lengthened by Quickchargepower? It seems like there is definitely a problem with the splice points.

I'll be reaching out to them to see what they say about it since it's barely been over 3 months. I remember seeing a rep from quickchargepower posting here in the past but can't seem to find him to tag for any input.

Resolution: Problem with UMC lengthened by Quickchargepower

Just wanted to update this post in case anyone happens upon it on a search for Quickchargepower.

I contacted them and sent the umc back using my invoice number as the RMA. They repaired it free of charge. It only cost me the shipping to get it back to them which was still over 50 since I'm East coast. Only took just over a week to get it back. Cable works great now. No mention of what was causing the issue with the first extension but kudos to them for taking care of the problem.

 

[jebinc]

I thought I remembered someone posting about a problem recently with their QCP extended UMC cable but I couldn’t find it earlier with search to post here ... then the OP @Machostallion posted an update a few hours ago and the thread got bumped

Problem: Problem with UMC lengthened by Quickchargepower
“the splice nearest the Tesla brick is uncomfortably hot. Also, I have noticed that the charge rate constantly goes up and down between 29 mi/hr and 14 mi/hr. The amps also get cut in half from 32 to 16.”



Resolution: Problem with UMC lengthened by Quickchargepower

@darth_vad3r - Thank you for finding this thread. My original fears about how QCP might accomplish the extension appear valid.

 

[Jonabramson]

I believe the max output of the mobile charger (at home) is 32 amps. While I'm not sure what gauge wire the mobile charger cable is, I suspect it is 8 AWG (given the 32 amp limitation and warmth of the cable when charging). The extension cord you are using is 6 AWG (thicker) wiring, which helps prevent voltage drops with added length. I suspect the wiring to your 14-50 outlet is also 6 AWG, so in a way, you extended your 14-50 outlet with the 6 AWG extension cord, and not the length of the mobile connector cable, which is likely (not sure) 8 AWG cable. This would explain why you are working just fine.

Does anyone know what gauge the mobile charger cable is? Whatever it is, if you choose to extend it, it's best to do so with a lower gauge (higher capacity) and high quality extension cable as @Bet TSLA did.

Just a quick note. The Gen 2 that comes with the M3 is limited to 32 Amps. If you purchase a Gen 1, it's limit is 40 Amps. I bought a Gen1 from someone and keep in plugged into my garage with the 50 amp outlet I had installed from my main. I keep the Gen II in the car for trips.

I've never checked or queried about the gauge of cable difference from the Gen 1 and Gen 2 but the cable sheath thickness is about the same. But I'll have to check it again for sure.

The issue I'd think with using an extension would be the plugging and unplugging. But other than that, it should essentially be no different from installing a cable directly if it's the same gauge.

 

[earthwormjim]

People are being a little ridiculous here, an extension is fine provided the wire gauge is adequate. What exactly do you think is running in your walls? If the extension wire gauge is the same as the wall wiring wire gauge, and the extension cable wire run ends up being about the same as relocating an outlet, then there is practically no difference.

If you want to be extra safe, then go 1 size down (larger) in wire gauge, than the minimum needed to handle the circuit's rated current for a wall run, to account for the added thermal insulation, and close wire proximity in the cable that the extension cable jacket adds. For example for 30A, you should use a minimum of 10 gauge wire for wall wiring, for the extension cable, pick at least 10 gauge and if you want to be extra safe or minimize the voltage drop, do 8 gauge.

 

[XLR82XS]

The issue I'd think with using an extension would be the plugging and unplugging. But other than that, it should essentially be no different from installing a cable directly if it's the same gauge.

That's why I turn the breaker off. The 240 for the Tesla is a dedicated circuit.

 

[jebinc]

That's why I turn the breaker off. The 240 for the Tesla is a dedicated circuit.

Similar problem. The breaker is not meant to be used like a "wall switch," and there are contacts in the breaker as well.

 

[davewill]

I see we've switched to extension cords. My feelings are that, assuming they are good quality and adequate wire size, they're OK for occasional use, like visiting family, but people shouldn't rely on them for daily use. The extra points of possible failure, tripping hazard, etc...better to bite the bullet and pay to have a circuit placed where you need it.

Now, frequent plugging and unplugging is an issue whether we're talking about an extension cord or not. If you want to take your mobile connector with you on a regular basis, I recommend either getting a second one to leave plugged in at home, or installing a wall connector.

 

[jebinc]

I see we've switched to extension cords. My feelings are that, assuming they are good quality and adequate wire size, they're OK for occasional use, like visiting family, but people shouldn't rely on them for daily use. The extra points of possible failure, tripping hazard, etc...better to bite the bullet and pay to have a circuit placed where you need it.

Now, frequent plugging and unplugging is an issue whether were talking about an extension cord or not. If you want to take your mobile connector with you on a regular basis, I recommend either getting a second one to leave plugged in at home, or installing a wall connector.

Hear, hear!

 

[darth_vad3r]

I see we've switched to extension cords. My feelings are that, assuming they are good quality and adequate wire size, they're OK for occasional use, like visiting family, but people shouldn't rely on them for daily use. The extra points of possible failure, tripping hazard, etc...better to bite the bullet and pay to have a circuit placed where you need it.

Now, frequent plugging and unplugging is an issue whether we're talking about an extension cord or not. If you want to take your mobile connector with you on a regular basis, I recommend either getting a second one to leave plugged in at home, or installing a wall connector.

OK, but what would you consider occasional use and not daily use? I charge at home 0, 1, or 2 nights a week, and charge at work 5 times a week. I'd say I average a home charge less than once a week so far on average, but maybe it might be approaching 30-40 times a year max if I use it more?

I leave the UMC at home*, next to the end of an extension cord of the appropriate gauge (I'm only charging at 12A off a 15A 120V outlet ).
When I need to charge, I plug the UMC into the extension cord, then into the car.

Since I'm getting by with only 120V charging at home, I don't see any real push for me to add expense of getting a Wall Connector and new circuit put in. I don't need the fast charging at home. Even if I had to plug in 5 times a week this way, I would get enough charge for my commute without charging at work... I'd probably still not bother getting a Wall Connector. Maybe if we become a 2-EV family at some point.


EDIT:
*Of course, if we go on a trip I take the UMC with me in case of emergency requirements to use NEMA 5-15 or 14-50 if no L2 or Supercharger available.

 

[algra]

Hi folks, picked up my M3 AWD last Friday, had a 14-50 circuit and outside outlet installed today. I got the Camco 30' 50 amp cable that others have mentioned. My question is whether it's ok to leave it hooked up and connected to the UMC that came with the car. The run from the outlet is to a carport across a driveway, so the connection is outside and exposed to the elements. Does the connection from the Camco to the UMC need to be weatherproofed. Has anyone done that?

 

[jebinc]

"Crickets"

Nothing from OP or @TonyWilliams (QCP)...

Well, three weeks have passed, and nada... Was kind of hoping to hear a response from QCP (@TonyWilliams) on this, but guess not...

 

[davewill]

OK, but what would you consider occasional use and not daily use? I charge at home 0, 1, or 2 nights a week, and charge at work 5 times a week. I'd say I average a home charge less than once a week so far on average, but maybe it might be approaching 30-40 times a year max if I use it more?

I leave the UMC at home*, next to the end of an extension cord of the appropriate gauge (I'm only charging at 12A off a 15A 120V outlet ).
When I need to charge, I plug the UMC into the extension cord, then into the car.

Since I'm getting by with only 120V charging at home, I don't see any real push for me to add expense of getting a Wall Connector and new circuit put in. I don't need the fast charging at home. Even if I had to plug in 5 times a week this way, I would get enough charge for my commute without charging at work... I'd probably still not bother getting a Wall Connector. Maybe if we become a 2-EV family at some point.


EDIT:
*Of course, if we go on a trip I take the UMC with me in case of emergency requirements to use NEMA 5-15 or 14-50 if no L2 or Supercharger available.

Somewhere between once a day and once a month .

Seriously, there's no rule. In your case, the deciding factor (for me) would be that you've got an extension cord connected and strung around your garage all the time. That says to me that it's not occasional, it's permanent. The size of the circuit isn't the relevant factor. If you want to use 120v 15a, as your regular home charging circuit, that's fine, but I would personally make the effort to install an actual outlet close enough to use...and spend the money for a UMC that I could leave plugged in. (Of course if you're going to spend money, a bigger circuit would undoubtedly be more convenient...)

That doesn't mean you won't get by just fine for the foreseeable future as you are, it's just outside what I'm willing to recommend people do.

 

[darth_vad3r]

Somewhere between once and day and once a month .

Seriously, there's no rule. In your case, the deciding factor (for me) would be that you've got an extension cord connected and strung around your garage all the time. That says to me that it's not occasional, it's permanent. The size of the circuit isn't the relevant factor. If you want to use 120v 15a, as you regular charging choice, that's fine, but I would personally make the effort to install an actual outlet close enough to use...and probably spend the money for a UMC that I could leave plugged in. (Of course if you're going to spend money, a bigger circuit would undoubtedly be more convenient...)

That doesn't mean you won't get by just fine for the foreseeable future as you are, it's just outside what I'm willing to recommend people do.

Ya, the extension cord is basically permanent, because it supplies Christmas lights (LEDs) 2 months out of the year so I just leave it where it’s convenient all year for that and any other occasional use outside the garage (vacuuming car, etc), but I only occasionally use it with the UMC. For example, the UMC has been untouched in my frunk for a couple weeks since I took it on a trip. I probably have charged at home maybe about a dozen times over 5 months. That might go up in the winter to facilitate morning warming. We’ll see.

 

[davewill]

Ya, the extension cord is basically permanent, because it supplies Christmas lights (LEDs) 2 months out of the year so I just leave it where it’s convenient all year for that and any other occasional use outside the garage (vacuuming car, etc), ...

To my thinking, all the more reason to put in a proper outlet...and a very good reason for that outlet to be GFI protected. Let's face it, many more people come to grief over Xmas lights than over EV charging. Not to mention that you should plan on not charging and running the lights at the same time on the same circuit...and really not on the same extension cord.

 

[darth_vad3r]

To my thinking, all the more reason to put in a proper outlet...and a very good reason for that outlet to be GFI protected. Let's face it, many more people come to grief over Xmas lights than over EV charging. Not to mention that you should plan on not charging and running the lights at the same time on the same circuit...and really not on the same extension cord.

They are LEDs. One strand is ~2W. It would take 60 strands to get to 1A! (I don’t have 60 strands)

Even if I did (which I don’t), I could dial back from 12A to 11A in the car.

I also don’t actually think running 13A on a 15A continuous for 12 hours through appropriate gauge extension cord (12 AWG or larger) would be an issue. And certainly not 12.25A say if I had even 15 strands.