justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Mon Jul 24, 2017 6:39 pm

So I was using my Duosida at home In my garage and also outside at my work. We had some excessive rain here in the Chicago area and my water proof (resistant) unit got under water apparently. When I got home the unit was faulting. I opened the ends with the o ring seals and shook a few drops of water out. I blew some air through the unit sealed it up and it worked. It worked that evening and the next day at work but after that point in time it has failed. I took it apart and dried it out completely but no dice. So I ordered a new unit online. The advertisement did not indicate the plug type but I figured I would make anything work. I received it today and it came with a standard 15amp plug!

GdB
Posts: 135
Joined: Tue Aug 12, 2014 4:06 pm

Re: Modifying the EVSE charger?

Wed Jul 26, 2017 12:31 pm

JoeS wrote:
GdB wrote:...The receptacle wiring being 14g or thinner wiring is the only reason for 20% derating. A 5-15P could pull 14 Amps all day with 12g wiring, the 20% derate limit is 16 Amps.
I didn't know that. Source?


No source just common sense. But I was thinking about this and found this interesting source relating to the 20% derate...

https://www.copper.org/applications/electrical/building/pdf/bundle_evaluation_report.pdf
They tested worst case wire bundles at high ambient temperatures.
The tests results presented are for 12g, but they say very similar results for 14g.

I'm glad I used 4g or 6g, and undersized the breaker just to minimize losses...
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

GdB
Posts: 135
Joined: Tue Aug 12, 2014 4:06 pm

Duosida EVSE Thermal 15-5P plug

Wed Jul 26, 2017 12:50 pm

14-2 Solid NM-B W/G Romex Wire is rated to 90°C, but should be limited to 60°C.


2 of these in parallel with an angle plug placed in a small project box would allow receptacle thermal protection, assuming the plugs and receptacles are also good to 75°C.:

http://www.allelectronics.com/item/thsw-167/thermal-protector/1.html
KLIXON 9700K251-48. Normally-closed thermal protector designed for motors, fluorescent ballasts and temperature sensing controls. Opens 75°C (167°F). Closes 50°C (122°F). Rated 13A / 250Vac. 3" lead length.
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Wed Jul 26, 2017 4:50 pm

Image

justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Wed Jul 26, 2017 4:54 pm

Image

15 amp plug.

justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Wed Jul 26, 2017 7:00 pm

This replacement Duosida EVSE was shorter than my first one and so it did not reach my garage outlet. So I first used it with an extension cord I already had. This was a cord with 16 AWG wire. It got hot so I went to buy a 12 AWG cord. I decided to get a 14 AWG cord to see if that got hot. Upon using this new extension cord I found it did not get hot. It was only very slightly warm almost imperceptible.

GdB
Posts: 135
Joined: Tue Aug 12, 2014 4:06 pm

Re: Duosida EVSE

Wed Jul 26, 2017 7:28 pm

justoneman wrote:This replacement Duosida EVSE was shorter than my first one and so it did not reach my garage outlet. So I first used it with an extension cord I already had. This was a cord with 16 AWG wire. It got hot so I went to buy a 12 AWG cord. I decided to get a 14 AWG cord to see if that got hot. Upon using this new extension cord I found it did not get hot. It was only very slightly warm almost imperceptible.


Wow that 16g wire was just a hot sunny day away from melting! But the fact that 14g did not get hot suggests a lot of conservatism in the 20% derate.

A lot of Ampacity tables don't show 16g.

Not sure if this one applies to home wiring, no mention of NM-B.
http://www.armstrongssupply.com/wire_chart.htm

This one is interesting in that it shows tables with and without derate:
https://xtronics.com/wiki/Wire-Gauge_Ampacity.html


econd version of the above table with 60°C trade derating - (affects ohms/kft and ohms/km.)
Max ambient 60°C

AWG *1 *2
16 22 13
14 32 17
12 41 23

*1 CU Max
free-air
Amps

*2 CU Max
enclosed
Amps

It seems like the 20% derate has been applied twice.
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Wed Jul 26, 2017 7:42 pm

GdB wrote:
justoneman wrote:This replacement Duosida EVSE was shorter than my first one and so it did not reach my garage outlet. So I first used it with an extension cord I already had. This was a cord with 16 AWG wire. It got hot so I went to buy a 12 AWG cord. I decided to get a 14 AWG cord to see if that got hot. Upon using this new extension cord I found it did not get hot. It was only very slightly warm almost imperceptible.


Wow that 16g wire was just a hot sunny day away from melting! But the fact that 14g did not get hot suggests a lot of conservatism in the 20% derate.

A lot of Ampacity tables don't show 16g.

Not sure if this one applies to home wiring, no mention of NM-B.
http://www.armstrongssupply.com/wire_chart.htm

This one is interesting in that it shows tables with and without derate:
https://xtronics.com/wiki/Wire-Gauge_Ampacity.html


econd version of the above table with 60°C trade derating - (affects ohms/kft and ohms/km.)
Max ambient 60°C

AWG *1 *2
16 22 13
14 32 17
12 41 23

*1 CU Max
free-air
Amps

*2 CU Max
enclosed
Amps

It seems like the 20% derate has been applied twice.

I knew the 16 AWG extension cord was inappropriate, but I wanted to se if it got hot. I only had it hooked up for about 10 mins and I monitored it the whole time.

justoneman
Posts: 83
Joined: Sun Apr 09, 2017 6:09 pm

Re: Duosida EVSE

Thu Jul 27, 2017 6:29 pm

justoneman wrote:Image

So what about this Duosida with the 15 amp plug?

JoeS
Site Moderator
Posts: 3232
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Duosida EVSE

Fri Jul 28, 2017 2:18 pm

justoneman wrote:...So what about this Duosida with the 15 amp plug?
We now know that plugging this thing into the i-MiEV will result in 14.0A-14.2A current draw, which exceeds the 12A max allowable for this type of an installation.

The EVSE wire leading to the 5-15 connector looks a little thin to me to have #10AWG or #12AWG wires inside it.

On a forum such as this, none of us can recommend doing something that's outside of code requirements; nevertheless, if you're going to be using the Duosida EVSE with 5-15, I'd be inclined to have it sit on a brick with the wires going to the wall outlet suspended in mid-air for maximum ventilation, and have nothing flammable immediately around the wire or connector if it should start cooking. I'd periodically check the connector/outlet to make sure it's not hot. Ambient air temperature also makes a significant difference.

Let us know how you fare, and perhaps measure and tell us what some of the temperatures are.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
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