User avatar
Ingineer
Posts: 2741
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 2:30 pm

It's possible that this is a deficiency of the Rema connector design used on the Blink. I compared it to the reference standard (Yazaki), and it appears that there are 3 deviations at work here that could be synergizing to create this failure:

1. The female contacts are captured very tightly in the housing, such that they are not as free to "self-align" to the male pins in the receptacle. The Yazaki has more freedom of movement.

2. The connector body is more loose in the receptacle housing.

3. The handle shape is more flat, so the cable exit is closer to straight out rather than angled down. This is causing the heavy cable to impart a lot more downforce on the body.

All these factors working together mean there is a good chance the self-aligning contact design of J1772 is being defeated in this implementation. Without sawing one in half, it's hard to know for sure, but based on what I can see, it sure looks bad.

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

User avatar
hgoudey
Forum Supporter
Posts: 55
Joined: Fri Jul 08, 2011 6:39 pm
Delivery Date: 03 Jul 2011
Leaf Number: 5132
Location: El Cerrito, CA

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 3:40 pm

While not a substitute for connectors that can handle the load, it would be relatively simple to add a subminiature thermostat in parallel with the proximity button switch on the J1772 handle. This would drop the charge current based on a connector temperature of one's liking (70-90C?) and restore charging when the temperature recedes, effectively imposing a thermally controlled charging duty cycle to protect the connector and perhaps alert when there is a heating issue. There's not a lot of space to internally fit the thermostat close to the pins with the LEAF inlet (without drilling into the plastic?), but the image of the RAV4 inlet shows voids between the pin sockets that should easily fit a small (~8mm) thermostat. I suppose the thermostat could be mounted on the EV inlet side rather than the EVSE plug/handle by dropping the resistance on the inlet side instead of paralleling the button on the handle. It just depends which side you want to protect all the time, and which you are willing to modify.

Howdy

MikeD
Posts: 702
Joined: Thu Jun 24, 2010 6:14 am
Delivery Date: 12 May 2011
Leaf Number: 592

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 4:40 pm

Ingineer: "It's too bad the J1772 pins were designed so thinly. They are about the same cross-section as a #12 AWG wire (3.6mm), which nobody would not consider sending 70 Amps though, let alone 30, but someone decided it was ok.".

I agree with your J1772 pin diameter, but not about your comparing that pin's diameter to that of a 12AWG conductor and therefore your conclusions about J1772 current carrying capacity.

Perhaps you misread a table, as according to NEC 2008/Table 8 (Conductor Properties) 12AWG (single strand) has a diameter of 2.05 mm, 10AWG (single strand) has a diameter of 2.588 mm, 8AWG (single strand) has a diameter of 3.264 mm. Using Wikipedia 7AWG (single strand) has a diameter of 3.665 mm and 6AWG (single strand) has a diameter of 4.115 mm.

I am not an expert on the current carrying capabilities of copper wire, but as you know the maximum current allowed for a given size wire is affected greatly by the thermal capacity of that wire's insulation. For example according to NEC 2008/Table 310.15 the 8AWG copper wire allowed ampacity for 140 degrees F insulation is 40, for 167 degrees F insulation is 50, and for 194 degrees F is 55. The corresponding numbers for 6AWG is 55, 65, and 75. Ampacities for 7AWG copper wire is not given, but since 7AWG's diameter is about half way between 6AWG and 8AWG, it is reasonable to estimate its corresponding ampacity numbers as 47, 57, and 65. There are other factors that can reduce the maximum current that can be handled safely, but 65a seems to me a ballpark figure for those pins.

It is important to note the J1772 inlet power pins are NOT insulated like conventional wires -- but they lead eventually to conductors that are and may be 6AWG or larger (anybody know J1772 inlet wire gauge for Tesla Model S?). So heat dispersal from those pins lead to those conductors and so the heat rating of that insulation must be taken into account. I don't know about the possibility of heat sinks between the power pins and the insulated conductors, but it doesn't seem to be a stretch to think that 3.6mm power pins might not be a problem at higher amps just looking at its current carrying capacity.

Now the reliability of the J1772 connection may be another matter entirely!

User avatar
JeremyW
Posts: 1545
Joined: Sun Nov 13, 2011 12:53 am
Delivery Date: 23 Jun 2012
Leaf Number: 19136
Location: San Gabriel, CA

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 5:07 pm

I know the Honda Fit EV has a thermistor of some sort on the j1772 inlet. Some have reported problems with heating on the Facebook page.
Former 2012 SL leasee 6/23/12 - 9/23/15
Former Fit EV leasee.
Now driving Spark EV and Model 3.

cwerdna
Posts: 10413
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 5:42 pm

JeremyW wrote:I know the Honda Fit EV has a thermistor of some sort on the j1772 inlet. Some have reported problems with heating on the Facebook page.
Hmmmm and the Fit EV has a 6.6 kW charger. I wonder if we'll start hearing more of these as other vehicles w/6.6+ kW chargers are deployed. It seems like it's just about everyone else other than the Volt, 2011-2012 Leaf, PiP and i-Miev.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 6:02 pm

cwerdna wrote:
JeremyW wrote:I know the Honda Fit EV has a thermistor of some sort on the j1772 inlet. Some have reported problems with heating on the Facebook page.
Hmmmm and the Fit EV has a 6.6 kW charger. I wonder if we'll start hearing more of these as other vehicles w/6.6+ kW chargers are deployed. It seems like it's just about everyone else other than the Volt, 2011-2012 Leaf, PiP and i-Miev.
I have not heard of a similar incident before. For what it's worth, I've been charging the ActiveE at about twice the rate of what the Leaf used to pull for the past eight months. There was a host of issues and problems with the car, but an overheated J1772 inlet was not one of them. That said, I only used a Blink station once, at Turbo3's place.Image

cwerdna
Posts: 10413
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 6:15 pm

surfingslovak wrote:
cwerdna wrote:
JeremyW wrote:I know the Honda Fit EV has a thermistor of some sort on the j1772 inlet. Some have reported problems with heating on the Facebook page.
Hmmmm and the Fit EV has a 6.6 kW charger. I wonder if we'll start hearing more of these as other vehicles w/6.6+ kW chargers are deployed. It seems like it's just about everyone else other than the Volt, 2011-2012 Leaf, PiP and i-Miev.
I have not heard of a similar incident before. For what it's worth, I've been charging the ActiveE at about twice the rate of what the Leaf used to pull for the past eight months. There was a host of issues and problems with the car, but an overheated J1772 inlet was not one of them. That said, I only used a Blink station once, at Turbo3's place.Image
Yeah, since I was there too, it wasn't being charged on his Blink EVSE for very long.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 6:17 pm

cwerdna wrote:Yeah, since I was there too, it wasn't being charged on his Blink EVSE for very long.
Yes, indeed. I'm fairly confident that the inlet on the ActiveE is from a different supplier. Several factors to consider here, and I would not pin it solely on the higher power draw. I've been enjoying the 6.6 kW charging for many months, and did not observe overheating.

User avatar
TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 7:26 pm

surfingslovak wrote:
cwerdna wrote:Yeah, since I was there too, it wasn't being charged on his Blink EVSE for very long.
Yes, indeed. I'm fairly confident that the inlet on the ActiveE is from a different supplier. Several factors to consider here, and I would not pin it solely on the higher power draw. I've been enjoying the 6.6 kW charging for many months, and did not observe overheating.
Here's something to consider. Tesla and Toyota drove the test mules and prototypes around with Tesla HPC connectors, and didn't add the J1772 until the car was closer to production.

cwerdna
Posts: 10413
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Blink / Rav4 Blows Out a Contactor Pin (with gory pics)

Tue Nov 27, 2012 7:35 pm

TonyWilliams wrote:
surfingslovak wrote:
cwerdna wrote:Yeah, since I was there too, it wasn't being charged on his Blink EVSE for very long.
Yes, indeed. I'm fairly confident that the inlet on the ActiveE is from a different supplier. Several factors to consider here, and I would not pin it solely on the higher power draw. I've been enjoying the 6.6 kW charging for many months, and did not observe overheating.
Here's something to consider. Tesla and Toyota drove the test mules and prototypes around with Tesla HPC connectors, and didn't add the J1772 until the car was closer to production.
Interesting...

And... Toyota's only other US plug-in, the PiP has a small battery and doesn't have a 6.6 kW charger. In fact, I think it barely goes much over 2 kW at 240 volts (this is OTOH... I don't recall what people have stated on Priuschat) and most of them probably just use the low amperage 120V Toyota provided EVSE (brick) since it's less than 3 hours at 120 volts to fully charge.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

Return to “EVSE / Charging Equipment and Networks”