So someone else mentioned this plug adapter in the forum the other day and so I went ahead and bought one. It allows you to get a NEMA 5-20 adapter for your UMC and plug it into this, and then plug this into a NEMA 5-15 receptacle.
First of all- This is NOT UL or NEC rated for what I am going to describe here. Use this information at your own risk! While the adapter does carry a UL rating, it is stamped saying not to use it over 15a so my use case is in violation of that.
This could be dangerous in the wrong hands! Basically the UMC adapter for a 5-15 outlet signals the car to max out at 12 amps. The 5-20 one lets the car draw up to 16 amps (the 80% derate of a 15 or 20 amp circuit respectively).
Please do not try to use this to draw more than 12a on a 15a circuit!
So the use case here is that you have a garage that has standard 5-15 receptacles all over the place (but they don't have the sideways notch that makes them also 5-20 receptacles). They are however backed by 12 gauge copper and a 20a circuit breaker. The only thing limiting you is the danged receptacle.
In my own personal garage this was the case, and so I just swapped the receptacles out to ones that could do either 5-15 or 5-20 (though I charge my car off a HPWC anyway).
Over the weekend I was at a friends vacation home where I had no good charging options. After some investigation, I found a 5-15 quadplex receptacle in the garage that was on a dedicated 20a breaker (intended for a freezer) and it had nothing else plugged into it. So I decided to try this adapter out. I was concerned that the receptacle was only UL rated for 15 amps and this adapter was only rated for 15 amps and so for the first couple hours I came out and checked it for heat with my hand every 15 minutes or so. It ran barely warm to the touch (some warmth is always expected).
Note that I was concerned at first when considering using this that perhaps the 20a blade was thicker/larger/had more metal than the 15a one, but then I realized the neutral (current carrying) conductor was identical for 15a or 20a. I also was worried about the receptacle in the wall might not handle it, though at some point someone linked to a teardown of one manufacturers 5-15 receptacle and it had the same guts in it as the 5-20 one (just the plastic on the receptacle blocked you from using the horizontal slot unless you paid for the overly expensive 5-20 receptacle). YMMV though...
The net-net is that I got 33% faster charging by being able to charge at 16a instead of 12a. It actually is probably more than a 33% gain since the fixed losses of running the cooling pump and such are the same either way.
Thought this might be useful info for others! But PLEASE be careful. I controlled for risks by using a circuit finder to figure out which breaker fed this, I removed the breaker panel cover and verified conductor gauge, I also removed the receptacle and verified the wiring was secure and not daisy chained on elsewhere. Then I only ran this way during waking hours and I regularly checked the warmth manually. I also had a fire extinguisher readily available.
Note that in theory there are thermistors in the UMC adapters to monitor receptacle heat. This likely defeats that safety mechanism to some degree as well.
https://www.amazon.com/AC-Connectors-Household-T-Blade-Adapter/dp/B017EUTHC0/
First of all- This is NOT UL or NEC rated for what I am going to describe here. Use this information at your own risk! While the adapter does carry a UL rating, it is stamped saying not to use it over 15a so my use case is in violation of that.
This could be dangerous in the wrong hands! Basically the UMC adapter for a 5-15 outlet signals the car to max out at 12 amps. The 5-20 one lets the car draw up to 16 amps (the 80% derate of a 15 or 20 amp circuit respectively).
Please do not try to use this to draw more than 12a on a 15a circuit!
So the use case here is that you have a garage that has standard 5-15 receptacles all over the place (but they don't have the sideways notch that makes them also 5-20 receptacles). They are however backed by 12 gauge copper and a 20a circuit breaker. The only thing limiting you is the danged receptacle.
In my own personal garage this was the case, and so I just swapped the receptacles out to ones that could do either 5-15 or 5-20 (though I charge my car off a HPWC anyway).
Over the weekend I was at a friends vacation home where I had no good charging options. After some investigation, I found a 5-15 quadplex receptacle in the garage that was on a dedicated 20a breaker (intended for a freezer) and it had nothing else plugged into it. So I decided to try this adapter out. I was concerned that the receptacle was only UL rated for 15 amps and this adapter was only rated for 15 amps and so for the first couple hours I came out and checked it for heat with my hand every 15 minutes or so. It ran barely warm to the touch (some warmth is always expected).
Note that I was concerned at first when considering using this that perhaps the 20a blade was thicker/larger/had more metal than the 15a one, but then I realized the neutral (current carrying) conductor was identical for 15a or 20a. I also was worried about the receptacle in the wall might not handle it, though at some point someone linked to a teardown of one manufacturers 5-15 receptacle and it had the same guts in it as the 5-20 one (just the plastic on the receptacle blocked you from using the horizontal slot unless you paid for the overly expensive 5-20 receptacle). YMMV though...
The net-net is that I got 33% faster charging by being able to charge at 16a instead of 12a. It actually is probably more than a 33% gain since the fixed losses of running the cooling pump and such are the same either way.
Thought this might be useful info for others! But PLEASE be careful. I controlled for risks by using a circuit finder to figure out which breaker fed this, I removed the breaker panel cover and verified conductor gauge, I also removed the receptacle and verified the wiring was secure and not daisy chained on elsewhere. Then I only ran this way during waking hours and I regularly checked the warmth manually. I also had a fire extinguisher readily available.
Note that in theory there are thermistors in the UMC adapters to monitor receptacle heat. This likely defeats that safety mechanism to some degree as well.
https://www.amazon.com/AC-Connectors-Household-T-Blade-Adapter/dp/B017EUTHC0/
