Extension cords for outside charging.

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tigger19687

Well-known member
Joined
Feb 10, 2015
Messages
559
Location
MA
SO I am making this it's own thread so it doesn't get lost in my other one.

I did try to close the hatch on the 12g ext cord and the EVSE cord, but it was too thick so I didn't latch it. I have the plastic part that covers the latch section OFF. But I don't want to Crimp the cords at all.

I realized today that I don't need the Ext cord and just have a small fabric bag that hangs over the outlet and holds the EVSE box up. This way it is not hanging hard by the plug as it is 4 feet off the ground and hides it. The cord goes to the ground, reaches around to the other side and plugs in. so there is room to spare.
I back in so that the White J-Plug doesn't stand out as much on my Black 'i' .

Maybe I should paint the J-plug black .

On the fact that I used a 12g. I have read all sorts information on if you should or shouldn't.
I would rather not have a error that might harm my car/plug and not cause a fire.
 
If you're using the stock cord that came with the 2012's, it charges at 8 amps, which would be fine for a 14 gauge cord. I have a 15 ft. 14 gauge cord that I use to charge at 12 amps and don't have any issues, except for the inlet cord on the EVSE getting hot (how does a 20 amp twist-lock plug get that hot with only 12 amps going through? I'd hate to see if I used 16 amps).

Mitsubishi tells us no, but based on other verbage in the manual, it's there to cover their butts if someone decides to charge through a 100 foot, 14 or even 16 gauge extension cord. That wouldn't be good. At 8 amps, a 14 gauge extension cord should be fine, as long as it's shorter than 20 ft. If you're going for a 20 footer or longer, then I'd go with 12 gauge. If you have the EVSEUpgrade, then I'd set it for 10 amps. It seems to charge just as fast and doesn't heat up the connections as much as 12 amps. Who knows what shape the outlet itself is in or what else is on that circuit.

For hanging the EVSE directly from an outlet, there are loopholes where you can tie a string and hang it from the outlet box. Or, if you don't want to worry about securing a bulky control box, the AeroVironment Turbocord is nice and compact.
 
The ext cord I have is 25', so I figure the 12g is better long term if I want to use it for future stuff ;)

Yes, my plug to EVSE goes warm up but not the rest of the cord (no ext cord) and I thought the same thing. Kinda strange.

I noticed the hole, now that you mention it. I like the fabric bag (hunter green color) as it kind of hides it a little, plus I can just put the rest of the wires in it when done.
 
tigger19687 said:
The ext cord I have is 25', so I figure the 12g is better long term if I want to use it for future stuff ;)

Yes, my plug to EVSE goes warm up but not the rest of the cord (no ext cord) and I thought the same thing. Kinda strange.

I noticed the hole, now that you mention it. I like the fabric bag (hunter green color) as it kind of hides it a little, plus I can just put the rest of the wires in it when done.

This another topic you won't get two people to agree on (even well educated ones). Extension cords for continuous loads should be as heavy of gauge as possible and practical (ease acquiring and using). I wouldn't suggest anyone use anything less than a 12 gauge cord for charging one of these cars (8 or 12 amps rate). Why? Voltage drop is very important and as we all have noticed the Prongs and receptacle of plugs are a significant source of resistance (plugs get warm). A 12 gauge cord will have heavier gauge prongs and connections to them.

There is voltage drop in the structure wiring before we even get to our cord.

There is voltage drop in every connection and relay along the way. Including the contactors in the car and the relays in the EVSE. I see my "i" charging at significantly different rates on L1 (observing canion). Even with the same EVSE and the same circuit in the garage! One with EVSE plugged directly into the receptacle closest to the car is 8% slower charge rate than the same equipment plugged into the same circuit but the outlet right by the breaker panel in the garage, reached with a 50 ft 12 gauge extension cord. Same amperage is pulled either way on the AC side, but much more voltage drop taking the longer route through the walls of the structure with smaller wire and many more connections along the way.

Does any of this matter really? It depends on how well you wish to treat your onboard charger in the car. It's optimized for certain voltages and can deal with some variation up or down from that. However the more variance from optimum, the more stress there will be on the charger (i.e. earlier failure of electronic components). 12 gauge only - is my advice.

EVSE plugs get warm because the cable and plug are sized from a chart, not for best practice. I recently saw the EVSE for a 2012 (8 amp only), the pigtail was 16 gauge. That's unacceptable in my book but it does fit the charts because of it's short length. Put a 12 gauge pigtail and male plug end on that same unit and no more plug warming (unless the receptacle it is plugged into is in pretty poor condition). Plus charges will take less time (less voltage drop) and less electricity wasted heating the cords and plugs.

As an aside the cords do fit under the hatch door (without crimping) if you only close it to the safety catch. It's still locked and no one will know but you.

Aerowhatt
 
PV1 said:
If you're using the stock cord that came with the 2012's, it charges at 8 amps, which would be fine for a 14 gauge cord. I have a 15 ft. 14 gauge cord that I use to charge at 12 amps and don't have any issues . . . . . .
Actually, if he's charging at only 8 amps and his extension is short (8 to 12 feet) a 16 gauge cord would work just fine. The conductors between the EVSE and the J-1772 plug are only 16 gauge and many of us charge at 14 amps using those wires

True, a heavy, continuous load will eventually cause smaller wires to get warm and if that load was a motor or some voltage sensitive load, the voltage drop in the small cord could pose a problem, but our EVSE's don't really care about voltage drops. On L1, the car will charge with anything between about 90 and 140 volts, so if you plug your 16 gauge extension into a 120 volt outlet and the cord drops 10% (not likely) you'd still be charging on 108 volts which both the car and the EVSE would find perfectly acceptable

For charging at work where you want to keep the EVSE locked securely in the car, I would buy a flat extension cord as opposed to a round one - The flat one will allow you to close and lock the rear hatch. 14 gauge is heavier than you need and it will not get as warm as the 16 gauge J-1772 cord does

Don
 
Don said:
On L1, the car will charge with anything between about 90 and 140 volts, so if you plug your 16 gauge extension into a 120 volt outlet and the cord drops 10% (not likely) you'd still be charging on 108 volts which both the car and the EVSE would find perfectly acceptable

Personally I don't think "acceptable" is a good enough standard, Optimal is a far better one. While the charger electronics will tolerate a wide range they are designed to work best, with the least stress right in the middle of the "acceptable" range. I've seen plenty of "acceptable range" designs fail (some in spectacular fashion). Optimal range designs don't! Since you have no idea which standard was used (if one even was used) upstream of your connection to the grid, it's far better to be wise and not just add insult to injury by using a minimalist approach to selecting the gauge of ones extension cord. If indeed the EVSE cord is 16 gauge that is more reason to feed it with 12 gauge, not less.

Just because I can survive eating cardboard, some dirt, and occasional road kill scraps does not make it an optimal way to survive. Sorry but a 16 gauge recommendation is just bad advice, plain and simple. nuff said

Aerowhatt
 
The National Electric Code would disagree with you. For an 8 amp load, 16 gauge conductors are more than enough. The voltage drop on a 16 gauge, 15 foot extension cord (30 feet total loop) supplying 8 amps of power is less than 1 volt. 120 volts in one end, more than 119 out the other end - Pretty darned close to 'optimal' in electrical terms

On an EVSE Upgraded unit charging at 12 amps, the same 16 gauge cord would drop less than 1.5 volts. I personally would recommend 14 gauge for a 12 amp load, but you'd be 'legal' with 16. If you want to discuss 'less than optimal' take a look at the cord on your vacuum cleaner - That undersized cord is powering a motor where voltage drops are more important - When the motor slows because of the lower voltage, the current it draws increases which begins a vicious cycle. Despite that, most vacuum cleaners with 12 or 14 amp motors come with 25 or 30 feet of 16 gauge wire

Go easy on the cardboard, but 119 volts out of the EVSE isn't going to harm a single thing on the car

Don
 
The thing to remember, too, is that grid voltage varies quite a bit. One house or business may well be feeding 120 volts on the nose, but other places may be pushing 110 volts or less. At my house, I often see level 2 voltages in the 245-253 volt range, especially at night after a considerable decrease in outside temperatures. At some commercial charging stations with 3-phase power feeding the building, I may only see 200 volts coming in, even though the nominal voltage is 208 volts.

So, while there is a big difference between the acceptable input and optimal input, the charger itself isn't much more than a rectifier/inverter with a transformer, fairly simple switching power electronics. Two separate systems outside of the charger manage power input on/off and the charging rate should something go wrong with the charger.

We could debate this until the cows come home, but I personally feel a volt or two line loss won't make much difference to the charger when the grid voltage can vary by 5 volts or more during a given charging session. Sure, smaller wires may be less efficient by causing more resistance, but level 1 charging in and of itself is considerably less efficient when compared to level 2. Quiescent loads are activated longer, resistive losses are in effect for a longer amount of time, the batteries themselves continuously warm with charging current, and the charger is getting warmer. My car gets less miles/kwh wall to wheels on level 1 than on level 2, and my batteries end up being warmer with the slower charge.

For 8-10 amps, I find 14 gauge wires offfer a good balance between ampacity and ease of use (able to fit under the hatch when closed). 14 gauge is the smallest I'm comfortable with, same as Aerowhatt standing by 12 gauge wire. The other option, if it exists, is a flat 12 gauge extension cord, where the three conductors lay side by side in the cable. Or, like I've seen in some pictures here, run the cords through the right rear window, though that leaves the interior vulnerable to rain, dirt, and insects, and is not nearly as stealth.

As a side note, if anybody has seen the pins in Tesla's mobile connector on the wall side, you'd be amazed that they pull the amps they do. :shock:
 
Or take a look inside a Tesla EVSE aka HPWC (High Power Wall Connector) 80 Amps at 240 vac

Crispy
hpwc_burnedup.jpg


and Hot
hpwc_flirimage.jpg
 
Don said:
The National Electric Code would disagree with you. For an 8 amp load, 16 gauge conductors are more than enough. The voltage drop on a 16 gauge, 15 foot extension cord (30 feet total loop) supplying 8 amps of power is less than 1 volt. 120 volts in one end, more than 119 out the other end - Pretty darned close to 'optimal' in electrical terms

On an EVSE Upgraded unit charging at 12 amps, the same 16 gauge cord would drop less than 1.5 volts. I personally would recommend 14 gauge for a 12 amp load, but you'd be 'legal' with 16. If you want to discuss 'less than optimal' take a look at the cord on your vacuum cleaner - That undersized cord is powering a motor where voltage drops are more important - When the motor slows because of the lower voltage, the current it draws increases which begins a vicious cycle. Despite that, most vacuum cleaners with 12 or 14 amp motors come with 25 or 30 feet of 16 gauge wire

Go easy on the cardboard, but 119 volts out of the EVSE isn't going to harm a single thing on the car

Don

A myopic view. Your assumption is that the loaded voltage at the plug connection point to the structures grid is at 120 volts. It's a wrong assumption and bad practice. There is voltage drop all along the way from the mains at the meter. One thing you are right about is that 119 volts out of the EVSE is alright for the cars charger. But that is not what you will have with a 16 gauge cord, or even a 12 gauge cord for that matter. If one is lucky the voltage at the wall receptacle under the cars load will be 115 to 117 with 120 at the mains (meter socket). That's if you don't have the clothes dryer, oven or air conditioner running in the building. If they, are subtract another 2 to 5 volts. Now add the unnecessary drop of the bad choice of a 16 gauge cord. Now we are out of myopic calculations and into the realm of real world measured values. Don't forget that your utility company may only be supplying 116V (or less) at your mains (meter) during peak loads on their grid finger that serves your house.

A vacuum cleaner is an intermittent load and therefore an inappropriate comparison to continuous load. Oh and by the way if your vacuum needs a new cord on it. Go with 12 gauge (or at least 14) and the vacuum will suck better and last longer.

16 Gauge is plain bad advice for the real world. Additionally, extension cords are flexed and usually fail due to some of the fine wires used to reach the labeled gauge breaking unseen inside the cord. In an undersized cord, it is barely managing when new. Some wear and tear and it becomes a fire hazard with voltage drops in the double digit percentages. A very very well worn 12 gauge cord eventually becomes as bad as your brand spanking new 16 gauge is out of the box. We need to ask ourselves, do I want to start out at the edge or have a buffer zone?

Aerowhatt
 
PV1 said:
Sure, smaller wires may be less efficient by causing more resistance, but level 1 charging in and of itself is considerably less efficient when compared to level 2. Quiescent loads are activated longer, resistive losses are in effect for a longer amount of time, the batteries themselves continuously warm with charging current, and the charger is getting warmer. My car gets less miles/kwh wall to wheels on level 1 than on level 2, and my batteries end up being warmer with the slower charge.

I do too. While your are correct about the percentage of the power actually going to charging being higher on level 2. Charging at higher rates is somewhat less efficient for all batteries that I am aware of. I measured a 1.63 volt drop through my level 1 EVSE that came with the car, at 12 amp rate (8amp switchable to 12 amp). My level 2 is wired with #8 wire (30 amp breakers) and has large high amp contactors. Measuring from inlet to outlet side on it the voltage drop is in the .02 volts realm while charging the car at 13.1 amps. Now, how much of the "less efficiency" on level 1 comes from where can't be quantified completely (not by me anyway). Some of it is definitely coming from the large feed conductors and contactors improving overall charging efficiency of the L2 system. Large low resistance connections and conductors are always better!

Aerowhatt
 
The official Mitsubishi rating for the supplied Panasonic EVSE input voltage is 100 to 250 volts - Anywhere in between is acceptable and will work just as well as any 'preferred' voltage . . . . . although, officially, there is no 'preferred voltage'

The onboard 3.3 KW charger uses a double rectification process, which makes it very versatile. Whatever AC 50 or 60 Hz voltage you feed into it is rectified to DC which is then converted back to high frequency AC to feed the rectification and regulation process, so the battery pack always sees the exact 360 ripple-free DC that they designed the battery pack to be charged with
http://myimiev.com/forum/viewtopic.php?f=22&t=1750

Don
 
Don said:
The official Mitsubishi rating for the supplied Panasonic EVSE input voltage is 100 to 250 volts - Anywhere in between is acceptable and will work just as well as any 'preferred' voltage . . . . . although, officially, there is no 'preferred voltage'

The onboard 3.3 KW charger uses a double rectification process, which makes it very versatile. Whatever AC 50 or 60 Hz voltage you feed into it is rectified to DC which is then converted back to high frequency AC to feed the rectification and regulation process, so the battery pack always sees the exact 360 ripple-free DC that they designed the battery pack to be charged with
http://myimiev.com/forum/viewtopic.php?f=22&t=1750

Don

Congrats Don, you just made my intractable list. Use your small gauge cord and depend on your good luck. Heck why not go 18 gauge it's lighter and easier to carry and store? Good luck! you do apparently need it.

Aerowhatt (has left this "discussion")
 
Aerowhatt said:
Congrats Don, you just made my intractable list. Use your small gauge cord and depend on your good luck. Heck why not go 18 gauge it's lighter and easier to carry and store? Good luck! you do apparently need it.

Aerowhatt (has left this "discussion")
Easy, guys. This is reminiscent of the quick charger discussion a while back. Don was simply quoting the specs on our charging equipment.

While bigger wire is generally better, 16 gauge wire is well within spec for an 8 (actually 7.5) amp load. The maximum continuous load rating is 10 amps. True, I personally wouldn't run that small of a wire, but per the National Electric Code and Underwriters' Laboratory, it is OK to do so, especially with how snug the Leviton plug is on the stock EVSE. A 14 gauge extension cord is rated for 12 amps continuous load, and 8 amps is well below that. Plus, it will easily fit under the bottom edge of the hatch. That is the cord I use.

If I was running a dedicated outlet for level 1 charging, I would definitely use 12 gauge wiring and 20 amp outlets. If an extension cord was needed where the EVSE didn't need to be secured in the vehicle, that is also the cord size I would use, but off-the-shelf 12 gauge extension cords are just too tight to fit without damage. If you know how to wire receptacles, you could buy direct-burial 12/2 and put weatherproof plugs on it. Then you would have a 12 gauge extension cord that would easily fit under the hatch.

Back to the original post. That's good that you found a way to suspend the EVSE from the outlet box. That, with a J-plug lock, should work just fine for everyday use. No extension cord needed.
 
I usually find that the plug at the ends are the limiting factor, as they tend to be warmer than the wire itself. While small gage still works and within spec, I would rather go larger size to reduce wasting watt-hr by conductive heating. A larger cord, like 12 or 14-awg runs cooler, thus less waste.
 
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