Charging 2015 Spark EV with an extension cord

[Sasquatch]

Hi guys,

Just bought our new Chevy Spark EV 2015 yesterday and it has been a rollercoaster of emotions. So excited and invigorated at first, down with the man and all that and now realize charging the thing is quite a task in Santa Monica/Westside LA.

We planned on setting up an extension cord at home and it isn't working. The light on the charger blinks red and the green charge light does not illuminate. Any tips? I'll be royally upset if we really cant use an extension cord at home.

Thanks!

 

[NORTON]

First, you have to use a 12ga. extension cord, or maybe a 10ga.if you are going more than 50 feet.
Do not use a cheap 'christmas lights' extension cord.

But your problem is probably the outlet you are plugging into.
Go down to the 'Depot' and buy an $8 outlet tester. It will show if the Hot, Neutral and Grounds are where they should be. Keep this with your car and the extension cord in case you need it again somewhere.
If this outlet is on your property treat yourself to a new quality outlet, one with screws for the wires, not the cheap 'push in' kind.
And make sure nothing shares that outlet at your place, like a beer fridge in the garage.
When you are sucking up the power at 12 Amps and you are on a 15 Amp circuit breaker, you are at the limit for continuous duty.

Good luck ! And welcome to the future !!!

 

[xylhim]

I would be wary of charging with an extension cord. I think the power draw ends up being substantially greater with this setup, and you're more likely to trip a breaker. I also fried a powerstrip using this method once.

 

[NORTON]

Sasq,

What's the difference between a 12 ga. wire in the wall and a 12 ga. extension cord? Nothing.
As long as the outlet is a good one every thing will be fine.
Replace the outlet with a quality unit and touch all the cord connectors to see if you can feel any heat after hours of charging.
You can even use a 'Killawatt' and measure your usage.

But really you need an L2 EVSE at home.

 

[emv]

Indeed, check the outlet to see if it is properly wired and that it is in good condition.

Since you will want to set the charge rate at 12 amps ( and you have to do this each each time you start to charge) this will ideally be a circuit not used by anything else. Also be wary of three potential problems: tripping over the cord, theft of the cord, and mischievous unplugging.

If you need to use an extension cord use a high quality cord and use this rule of thumb for sizing. Remember that in AWG numbers, smaller is thicker.

Up to 25 Feet, 14 gauge
Up to 50 Feet, 12 gauge
Up to 100 Feet, 10 gauge

The fatter wire is to get around the problem of voltage drop. The longer the cord and the smaller the wire the more voltage you lose along the way.

If at all possible a hard wired Level 2 evse is the way to go.

 

[Zoomit]

+1 NORTON and emv speaketh the truth.

Be smart about it and it should be fine:
- use a single, 12 or 10 gauge, quality cord (no powerstrips or multiple extensions)
- don't have other loads on that circuit (not just the one outlet)
- use a 20 amp circuit (vs 15 amp) if possible
- don't let it be a tripping hazard
- don't put it where people will walk on it or ride a bike over it
- don't allow people to disconnect it while charging
- don't let the charger to extension cord connection be exposed to water or debris that could cause a spark if it touched the contacts

These are the reasons why the GM lawyers say to not use an extension cord. People can be ignorant of the risks, just try not to be one of them!

...and YMMV, I'm not an electrician.

 

[Sasquatch]

Thanks for all the responses. So you haven't gotten the red blinking light on the cord that came with the 2015 spark? We were using 35 ft 16 gauge so maybe that's the issue?

 

[Zoomit]

Along with the above advice to check the outlet, I'd try a 12ga 25 ft cord, if it reaches comfortably, and see what happens charging at 8 amps then at 12 amps.

Personally, I would never use a 35' 16 gauge cord to charge 12amps continuously.

 

[kevin]

+1 NORTON and emv speaketh the truth.

Be smart about it and it should be fine:
- use a single, 12 or 10 gauge, quality cord (no powerstrips or multiple extensions)
- don't have other loads on that circuit (not just the one outlet)
- use a 20 amp circuit (vs 15 amp) if possible
- don't let it be a tripping hazard
- don't put it where people will walk on it or ride a bike over it
- don't allow people to disconnect it while charging
- don't let the charger to extension cord connection be exposed to water or debris that could cause a spark if it touched the contacts

These are the reasons why the GM lawyers say to not use an extension cord. People can be ignorant of the risks, just try not to be one of them!

...and YMMV, I'm not an electrician.

I would add another

- Don't coil up the extension cord - stretch it out so it can keep cool or it could melt.

kevin

 

[Zoomit]

I didn't think of that. But frankly, if the cord is getting anywhere near hot enough to be concerned about melting, I would not be using it.

Certainly, shorter is better and uncoiled is better.

 

[Jedi2155]

Remember, heat builds up overtime, so you might not notice how hot it gets after a few minutes or a few hours but if you're charging via L1 over 10 or 20 hours, it will definitely be a lot worse.

 

[stevon]

NORTON,
The main difference is flexibility. Also more strands offers better current flow as current runs on the outside of a conductor in theory. Good welding cables have many fine wires packed in their cables. As long as the plug is overated for the current required and copper is securely bonded without corrosion to it's terminals You should be fine. I even "tin" or solder the copper before attaching to plug ends just as a precaution (overkill). There also this Tesla article:
http://my.teslamotors.com/forum/forums/solid-wire-vs-stranded-wire

Stephen

Sasq,

What's the difference between a 12 ga. wire in the wall and a 12 ga. extension cord? Nothing.
As long as the outlet is a good one every thing will be fine.
Replace the outlet with a quality unit and touch all the cord connectors to see if you can feel any heat after hours of charging.
You can even use a 'Killawatt' and measure your usage.

But really you need an L2 EVSE at home.

 

[NORTON]

stevon,

True, but in the wall wires would not need flexibility.
With a quality 15A rated wall outlet using 12A is right at the "80% continuous duty" rule, which is why you should go for the screw clamped outlets and not the cheapo 'Push-in spring lock' or whatever they are called. You could go with a 20A rated 120V outlet also. I saw a few examples on the Volt forum of 'smoked' old, cheap, mostly 'Push-in' outlets.

With flexible wires you don't want solder. In aviation most terminals are crimp type. Soldering a copper wire creates a 'theoretical' hardened area in the copper where the solder ends and the virgin copper begins. That's where the wire will break.

Besides, this is all talk about using L1 EVSE's at home and away.
Step it up and buy yourself an L2 for your home. That is what the future needs. And we are living the future now !!
If you are wiring your house for a new L2 outlet, step up the wiring for your next EV and run heavy gauge wires.

 

[stevon]

Norton,

Good point! copper is the only metal that gets stiffer with heat applied. The "tinning" is just for adding corrosion resistance and less fraying when installing. Mechanical type crimps and screws for copper wire electrical fasteners generally make the best connection using the crush force that they were designed to use.

stevon,

True, but in the wall wires would not need flexibility.
With a quality 15A rated wall outlet using 12A is right at the "80% continuous duty" rule, which is why you should go for the screw clamped outlets and not the cheapo 'Push-in spring lock' or whatever they are called. You could go with a 20A rated 120V outlet also. I saw a few examples on the Volt forum of 'smoked' old, cheap, mostly 'Push-in' outlets.

With flexible wires you don't want solder. In aviation most terminals are crimp type. Soldering a copper wire creates a 'theoretical' hardened area in the copper where the solder ends and the virgin copper begins. That's where the wire will break.

Besides, this is all talk about using L1 EVSE's at home and away.
Step it up and buy yourself an L2 for your home. That is what the future needs. And we are living the future now !!
If you are wiring your house for a new L2 outlet, step up the wiring for your next EV and run heavy gauge wires.

 

[bicycleguy]

I agree with all said before but must emphasize checking the outlet. The EVSE that came with the Spark has no way of knowing whether your cord is 18 gage or 2.

It will however check the ground and if there is leakage to it or it isn't connected the charger will not work. That is the whole reason for the EVSE. In order to keep you from electrocuting yourself come rain or wear or ignorance or malice it will check that there's an appropriate car connected, check that there is a ground, check for currents to ground and finally turn on the juice to your car.

 

[NORTON]

I agree with all said before but must emphasize checking the outlet. The EVSE that came with the Spark has no way of knowing whether your cord is 18 gage or 2.

It will however check the ground and if there is leakage to it or it isn't connected the charger will not work. That is the whole reason for the EVSE. In order to keep you from electrocuting yourself come rain or wear or ignorance or malice it will check that there's an appropriate car connected, check that there is a ground, check for currents to ground and finally turn on the juice to your car.

And I agree with your above statement. And if for some reason the EVSE is not happy with your 120V outlet you can test it with a $7 outlet tester from the 'Depot':http://www.homedepot.com/p/Gardner-Bender-120-VAC-GFCI-Outlet-Tester-1-clam-5-clams-master-GFI-3501/202867890
I keep one in the car with a 25' 12ga ext cord. Just in case...

This will not test the quality of the outlet, like the socket's grip on the plug pins and the condition of the wires connected to the outlet.
If you plan on charging at 12A 120V at home, do yourself a favor and replace the outlet with a quality screw type outlet.

 

[Dusty]

I agree with all of the above, especially about replacing the outlet. Most outlets today have both push-in and screw connectors. The problem with push-ins is the poor connection between the wire and the retaining barb which bites into the wire. The surface contact between the two can be so small it reduces the safe current capacity to 16 or 18 gauge or less, causing heat to build up. As mentioned by Norton, the solution is using the screw connectors on the side of the receptacle.

One potential pitfall is the receptacle itself. The cheap ones are only rated at 15 amps. It's common to find these on 20 amp circuits. Home Depot and Lowes sell a 20 amp receptacle for 2 or 3 dollars. While replacing, you can release the push-in barbs with a tiny screwdriver or tweezers from a Swiss Army knife. Turn the power off, of course.

Another consideration is the distance between the service panel and outlet. Voltage drops begin at the panel, not the outlet, and if the outlet is clear across your house, you might be losing a few volts before you even begin. I would also avoid using outlets which are daisy-chained together. The effective current capacity is only as good as the weakest connection. If the outlet you're using is push-in, they're probably all push-in, which might not even be safe at an 8 amp charging rate.

Finally, not all extension cords are created equal. In my case, until the L2 EVSE was installed, I used the dedicated washing machine circuit. (Wash by day, charge at night) It's rated at 15 amps and was only about 20' from the service panel. Then another 25' with a heavy-duty, 12awg extension cord to the charging cord that came with the Spark EV. Charging at 8 amps caused both ends of the extension cord to heat up, indicating less than optimum connections within the cord itself. I didn't even try charging at 12 amps. If using an extension cord and charging at 12 amps is a long-term solution, then invest in a contractor grade cord using 10ga wire. It'll be worth the peace of mind.

Dusty

 

[sTeeve]

I agree with all of the above, especially about replacing the outlet. Most outlets today have both push-in and screw connectors. The problem with push-ins is the poor connection between the wire and the retaining barb which bites into the wire. The surface contact between the two can be so small it reduces the safe current capacity to 16 or 18 gauge or less, causing heat to build up. As mentioned by Norton, the solution is using the screw connectors on the side of the receptacle.

One potential pitfall is the receptacle itself. The cheap ones are only rated at 15 amps. It's common to find these on 20 amp circuits. Home Depot and Lowes sell a 20 amp receptacle for 2 or 3 dollars. While replacing, you can release the push-in barbs with a tiny screwdriver or tweezers from a Swiss Army knife. Turn the power off, of course.

Another consideration is the distance between the service panel and outlet. Voltage drops begin at the panel, not the outlet, and if the outlet is clear across your house, you might be losing a few volts before you even begin. I would also avoid using outlets which are daisy-chained together. The effective current capacity is only as good as the weakest connection. If the outlet you're using is push-in, they're probably all push-in, which might not even be safe at an 8 amp charging rate.

Finally, not all extension cords are created equal. In my case, until the L2 EVSE was installed, I used the dedicated washing machine circuit. (Wash by day, charge at night) It's rated at 15 amps and was only about 20' from the service panel. Then another 25' with a heavy-duty, 12awg extension cord to the charging cord that came with the Spark EV. Charging at 8 amps caused both ends of the extension cord to heat up, indicating less than optimum connections within the cord itself. I didn't even try charging at 12 amps. If using an extension cord and charging at 12 amps is a long-term solution, then invest in a contractor grade cord using 10ga wire. It'll be worth the peace of mind.

Dusty

All good points. This part was of particular interest to me because I have a home automation system: "Most outlets today have both push-in and screw connectors. The problem with push-ins is the poor connection between the wire and the retaining barb which bites into the wire."

The HA system uses the house electrical wiring to send its wired signals. When I bought my house, I spent 3 months prior to move-in working on it, adding new circuits (4 banks of overhead lighting in the garage...yay!) plus recessed lighting.

I went through the entire structure and re-wired every outlet/wall switch...because *all* of them used the push-in connector...and rerouted the romex to the screw connectors. That allows the HA system to propagate its signals much more easily. Pays handsome dividends in that the HA system is reliable and solid. Doesn't hurt that the EVSEs have no troubles charging my EVs. Had an electrician install a 240V/50A service (NEMA 14-50) in the garage to future-proof EV charging capability...which in hindsight may not be as future-proof as I'd like, but 9.6 kW will suffice, since I'm mostly not in a hurry to charge the EV at home, and none of my EVs are capable of drawing that much power. Of course, I hope this will change in the next couple of years.

Had a buddy over for pizza and EV tire-kicking a couple of nights ago. He's converted a 1987 Toyota pickup to electric, has two onboard 2.5 kW chargers and an adapter to plug-in to J1772; he took 12.5 kWh of juice in the 4.5 hrs we charged. His battery pack is made up of two 10 kWh packs in the bed. He gets about 80 miles of range and has no GOM (!). He reads Ah and Wh and calculates his range in his head. Weird but effective.

-Bob K.

 

[Sparkler]

.... Also more strands offers better current flow as current runs on the outside of a conductor in theory.

From Wikipedia:

"At 60 Hz in copper, the skin depth is about 8.5 mm. At high frequencies the skin depth becomes much smaller."

So unless you are using wires larger than 8.5 mm you won't see _any_ effect. Welding wire uses many small conductors exclusively for the flexibility, the outer jacket is always thick rubber rather than the cheaper alternatives for the same reason.

see https://en.wikipedia.org/wiki/Skin_effect

If the effects at 60Hz were anywhere near what they are at 50MHz power companies would be using tubular conductors the way TV and radio transmitter antennas do. A common coax to feed RF from a high power transmitter to the antenna consists of about 5" copper tube, with a smaller tube suspended in the center by nylon spacers...

 

[motodirthead]

I had the same problem trying to use the 120V charger at home. The red light was because of a band ground on the outlet. The outlet must be grounded or the 120V charger will not function. Installing a L2 Bosch charger now of a 40A circuit.