It could also be backstab connections. They tend to get loose over time, in my experience, to the point that you can sometimes pull an outlet out of the box and the backstabbed wire pulls right out of the back of the receptacle. In my old house, I went through and pigtailed all of the connections to the outlets between the load center and the garage. I made up the pigtail with a wirenut and a short length of wire. I connected the pigtail to the outlet using the screw terminals. That way the circuit isn't daisy-chained through the outlet anymore, and the connection to the outlet is the more reliable screw terminals.
Charging Efficiency
- Thread starter dogememe
- Start date
It could also be backstab connections. They tend to get loose over time, in my experience, to the point that you can sometimes pull an outlet out of the box and the backstabbed wire pulls right out of the back of the receptacle. In my old house, I went through and pigtailed all of the connections to the outlets between the load center and the garage. I made up the pigtail with a wirenut and a short length of wire. I connected the pigtail to the outlet using the screw terminals. That way the circuit isn't daisy-chained through the outlet anymore, and the connection to the outlet is the more reliable screw terminals.
If it's getting hot then the outlet is either in need of replacement or there's a loose connection to that outlet. Or there's a bad connection in the 14-50 plug itself.
I've never experienced that issue with the rear stab connections failing but it makes sense. Then again 2 of my 3 houses have received "down to the studs" remodels & the 3rd had an obligatory replacement of ancillaries (including all outlets). I did find one of the outlets with an overtightened (and broken) screw terminal in use. Have a feeling all my outlets are still too new to run into these issues but will keep that in teh back of my mind.
Everything seems fine now, but some discussions make it sound like Leviton 14-50 outlets are a fire waiting to happen.
They probably aren't designed for frequent plugging/unplugging. Absent that, if it's not getting hot now, there's no reason why it would in the future.
If you've ever cracked apart an old outlet (which I sometimes do with Channelock pliers to make it easier to get the wires out of the backstab connection, if I'm replacing that outlet), it's easy to see why a frequently used (plug/unplug) outlet could develop a loose backstab connection. Every time you plug something in, the backstab connections move, ever so slightly. Enough of that and they'll get loose.
I pretty much always get spec-grade outlets for replacements. Hopefully that means I won't be doing the replacement again anytime soon.
Nah - my dad has a Tesla Mobile Connector and the plug is semi-permanent. He was worried about it hanging from the outlet and got a hanger so that the connector body is resting in the hanger. I think most users just let it hang from the outlet. Not this one, but something similar.
He actually got a hanger for the cord first, but then realized that he needed something for the charger body. And he could have just gotten a set originally, but the cheapest thing he could find for the body hanger came with a cord hanger. But overall it's an insignificant cost and should save on wear of the outlet.
And yeah it's pretty apparent why the Leviton outlet is $12 at Home Depot while a Hubbell costs $90 and is hard to find.
Any opinion on surface mount outlets?
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That could be the cause of a problem.
In my experience they're far more common than flush mount outlets when used for electric stoves, and the wire doesn't need to make any 90 degree bends to make a connection--it just lays straight in. There's also no need worry about grounding the metal box. I'd be more inclined to use a surface mount outlet. You can also easily pull the cover off and inspect the connections for overheating.
Agreed. I understand NEMA 14-50 receptacles are not meant for frequent plugging and unplugging.
If you want a receptacle that is, a California Standard CS8269 twist-lock receptacle is, but it's around $100 for that and around $100 for the California Standard CS8265C plug that mates with it. (For whatever reason, the NEMA L6-50 plug and socket were never popular, so the industry uses these California Standard plugs and sockets instead).
Not sure if that is the only issue. There are plenty of posts on 14-50 outlet fires, even on ones where they were not frequently plugged/unplugged.
Porsche put a statement in one of their TSB's about the importance of using an industrial grade 14-50 outlet.
Loose connections would be the other issue. The recommended Hubbell receptacle uses a hex head for the lugs, which precludes using any old crappy screwdriver laying around to make the connections.
I have an ECX bit for my screwdriver. This allows me to put enough torque on a regular receptacle to strip out the screw threads. You aren't doing that with a regular Phillips. (You might strip out the screw head, though).
Loose connections would result in heating. Charge the vehicle for 10 minutes, disconnect, check the plug blades to see if they're excessively hot.
I agree, most likely it won't be anywhere close to 10%. It is most likely on the 5% or so range, but depends on other factor including whether the inside of the car's charging circuit needs to turn on any cooling due to the higher current or not.
I have noticed that, in hot weather, charging in a closed garage, my Chevy Volt is more likely to turn on the AC compressor for cooling when charging at 240V@14A than it will when charging at 120V@12A. So if I charge it during the day in the summer when temps are often above 90F, I'll charge at 120V, if I don't need the increased charge rate of 240V so the battery is charged by my next trip.
Since I rarely need to do that (my daily driving rarely exceeds the battery range), I have configured delayed charge with a departure time of 6AM, using 240V. That way, it starts charging around 2-4AM when the outdoor temp is close to the daily low, often around 70F or even lower.
(Charging at 240V when it's 95F outside is likely to result in a garage that's 115F inside...and an AC compressor on the Volt working very hard to cool the battery)
240V @14A is more than 2x the power of 120V@12A, so it obviously would heat up more. Is there a possible choice of 240V @ 6A to compare against?
I do not have an EVSE that will allow charging at 240V @ 6A
If 8 amps is causing the outlet to get hot it's either worn out of the wires are loose. Most are rated 15 amp minimum. Better ones are at 20A.
The only thing a 120 vs 240 will do is faster as long as no excess heat is generated. Same amount of electricity otherwise.
The only thing a 120 vs 240 will do is faster as long as no excess heat is generated. Same amount of electricity otherwise.
The internals of a 15 amp and a 20 amp outlet are almost always identical. The only difference is the plastic face, which doesn't have the horizontal cutout so a NEMA 5-20 plug can be inserted.
Both 15 amp and 20 amp outlets are rated for a 20 amp feed through. This is one reason why the code allows the use of a 15 amp outlets on a 20 amp circuit, like the ones in your kitchen.
Like you I charge My C-Max Energi at home every night using 120 VAC. The C-Max also has an acceptance rate of 3.3 KW. I placed a P3 Killawatt meter beween the outlet and charger to measure what it was doing. In my case the charger draws a maximum of 1380 watts or 11.5 amps @ 120 VAC. I am not sure what the overhead consumption in while charging, but the charger continues to draw 1.5 watts once the charge is complete or the vehicle is disconnected. I am going to go out on a limb here and guess that the overhead is practically of no consequence,
One other observation you might find interesting: my battery is rated at 7.2 KWH but it takes only 6.95 KWH to charge it when drained below the level where EV mode is available. Assuming $0.18 per KWH and 24 miles per charge yields a cost of $0.0525 per mile. YMMV.
