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Charging on an extension cord

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widodh

Model S 100D and Y LR
Moderator
Jan 23, 2011
6,861
2,840
Venlo, NL
Tesla does not advise you to charge with an extension cord, but I knew I was going to a location where charging wasn't possible without one (20 meters), so I took one with me.

Normal extension cords here a 3G1.5, that means 3 wires of 1.5mm2 each. But I had a 25m 3G2.5 with me and that works great.

I'm currently charging on 13A over a total of 25m of extension cord, no problems.

All the wiring here in houses and buildings is 2.5mm2 by default, so it's not a real wonder that it works, but I thought I'd share it.

I however did notice a drop in voltage from 236V on idle to 218V during charging. That was more then I calculated.

I'd advice everybody to always have a 2.5mm2 extension cord with you instead of a 1.5mm2 to avoid the "extension cord" message from the Roadster. This message is mainly due to a high voltage drop when putting load on the wires.
 
I've charged with an extension cord on a couple of occasions (at hotels). As long as it's heavy-duty gauge wire it works just fine.

Another tip for Roadster owners is to use something like OVMS to set the amperage draw down an amp or two. What I've done is to start charging, then after an hour, bump the amperage up 1 amp. Then wait another hour and bump again. OVMS lets you do that remotely.
 
Another tip for Roadster owners is to use something like OVMS to set the amperage draw down an amp or two. What I've done is to start charging, then after an hour, bump the amperage up 1 amp. Then wait another hour and bump again. OVMS lets you do that remotely.
So is that where the term 'amped up' comes from? :tongue:
 
I carry a 10M extension cable and have charged at 32A overnight with no problems. The cable I use has 6mm cores and is both light weight and flexible. Here's my European travel kit :smile:

IMG_1706.jpg
 
I'm carrying about the same, but since 32A points here are rare I only carry 16A stuff. The Type 2 -> Tesla cable is 32A capable though since we have some 32A EVSE's out there.

I'd just advise everybody who is thinking about this to take a thick cable, that prevents the voltage drop. When the voltage drops below a certain amount (region specific) the Roadster refuses to charge.
 
Tesla does not advise you to charge with an extension cord, but I knew I was going to a location where charging wasn't possible without one (20 meters), so I took one with me.

Normal extension cords here a 3G1.5, that means 3 wires of 1.5mm2 each. But I had a 25m 3G2.5 with me and that works great.

I however did notice a drop in voltage from 236V on idle to 218V during charging. That was more then I calculated.

I'd advice everybody to always have a 2.5mm2 extension cord with you instead of a 1.5mm2 to avoid the "extension cord" message from the Roadster. This message is mainly due to a high voltage drop when putting load on the wires.

I'd actually advocate using 4mm2 cable for such a long extension cord. It should seriously limit voltage drop and heat.

I do not think a pre-made one will be available, so one has to buy the cable and connectors separately.
 
I'd actually advocate using 4mm2 cable for such a long extension cord. It should seriously limit voltage drop and heat.

I do not think a pre-made one will be available, so one has to buy the cable and connectors separately.

In the Nordic countries most homes only have the Schuko 220V/16A (or worse 10A) connector, except in the kitchen where almost everyone has a 25A (220-240V) outlet for the ocen/stove. I'm getting some quality 6mm cable and connectors and will make a 15-20m cord. When I visit people we'll unplug the stove, run the cable out a window opening and charge during the night.
 
I'd actually advocate using 4mm2 cable for such a long extension cord. It should seriously limit voltage drop and heat.

I do not think a pre-made one will be available, so one has to buy the cable and connectors separately.
1.5mm2 is sufficient for 16A, but you will get a big voltage drop, that's why I took 2.5mm2

The heat from 2.5mm2 is almost nothing, while 1.5mm2 gets pretty warm with 13A or 16A continuously.

I used this for calculating the drop: http://www.eclecticsite.be/calc/voltagedrop.htm

Imho 4mm2 is a bit too much. It will take up a lot of space in the Roadster as well. For the Model S I'll be using 2.5mm2 for 16A and 6mm2 for 32A for sure.

You also have to make sure you don't have to much connectors in between, since they will cause an even further voltage drop!
 
This forum is very stale, but I found it when trying to decide if I should try charging from a 120v outlet in Canada (which is NOT what this forum is about) with an extension cord.

I can report that it works fine, at least if you follow the caveats I found in various other places.

I bought a 50' 12 gauge extension cord from Canadian Tire (on sale for $33) and it worked fine. I get 215 or 216 volts on it at 12 amps. It does not overheat, nor does my Model S recognize a low enough voltage to realize I'm using an extension cord.

I'm tempted to just not bother installing a home charger.

I was thinking of buying a 10 gauge 50' cord from Home Depot, but I clearly will only get a few more watts out of it (i.e. the amps from my plug will still only be 12, so even if I get a few more volts, it won't make much difference) so I didn't bother because the 10 gauge 50' cord is $100.
 
This forum is very stale, but I found it when trying to decide if I should try charging from a 120v outlet in Canada (which is NOT what this forum is about) with an extension cord.

I can report that it works fine, at least if you follow the caveats I found in various other places.

I bought a 50' 12 gauge extension cord from Canadian Tire (on sale for $33) and it worked fine. I get 215 or 216 volts on it at 12 amps. It does not overheat, nor does my Model S recognize a low enough voltage to realize I'm using an extension cord.

I'm tempted to just not bother installing a home charger.

I was thinking of buying a 10 gauge 50' cord from Home Depot, but I clearly will only get a few more watts out of it (i.e. the amps from my plug will still only be 12, so even if I get a few more volts, it won't make much difference) so I didn't bother because the 10 gauge 50' cord is $100.

That's a typo. I get 115 or 116 volts, of course, on my 120v outlet.