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

[MikeD]

Ingineer: So your maximum temperature scanned = 141 deg F = 61 deg C, which is well below the 105 deg C rating of the car inlet power cables and the 90 deg C rating of the supply cable.

I'm guessing the ambient temperature is approximately the lowest temperature shown on the RHS (60 deg F = 16 deg C). If correct, then the maximum contact temp rise is also of interest to look at: in deg C have 61 - 16 = 45 deg C temp rise on the hottest inlet contact and 58 - 16 = 42 deg C temp rise on the hottest supply contact, both of which are less than the J1772 contacts maximum temperature rise of 50 deg C, but not by much. Of course it would be of interest to see if using other 30a EVSEs in comparable charging sessions show similar contact temperature rises.

I am struck by the fact that (visually at least) the temperatures of the two contacts aren't more nearly the same for the RAV4 since the current passing through each should be the same. It would be interesting to see other tests to see if this difference is consistent or if it varies by, say, how the nozzle is inserted, etc.

Comparing car inlets, since the LEAF inlet appears to have more solid material between the 5 holes for the contacts than that of the RAV4, it might support the nozzle more securely, i.e. allow less flexing of the inlet plastic and so provide for better contact mating, i.e. lower resistance and so consistently less contact heating during charging.

 

[TonyWilliams]

I can't wait to see thermal images at 40 and 75 amps.

 

[MikeD]

TonyWilliams: I'm not sure where a common situation would occur where one would have charging at about 40 amps, since all currently commonly sold EVs in this country except Teslas seem to be limited to 30 amps and I believe the on-board charger determines the actual current draw. [CORRECTION: Rav4 EVs can charge at 40 amps maximum]. The public J1772 Level 2 chargers all seem to be limited at most to 30 or 32 amps.

I'm not sure what the current limit for Teslas is with their J1772 adapter, I think it's 70 amps. The J1772 standard maximum is 80 amps.

I think the (more robust) Tesla J1772 contact pins are silver plated copper, whereas I've seen 30 amp J1772 contact pins described as nickel plated copper (and silver is more conductive than copper which is more conductive than nickel -- and then there are alloys).

It would be of interest to read exactly how the J1772 contacts are designed to mate and un-mate to get an idea what could go wrong.

 

[Ingineer]

Ingineer: So your maximum temperature scanned = 141 deg F = 61 deg C, which is well below the 105 deg C rating of the car inlet power cables and the 90 deg C rating of the supply cable.

I'm guessing the ambient temperature is approximately the lowest temperature shown on the RHS (60 deg F = 16 deg C). If correct, then the maximum contact temp rise is also of interest to look at: in deg C have 61 - 16 = 45 deg C temp rise on the hottest inlet contact and 58 - 16 = 42 deg C temp rise on the hottest supply contact, both of which are less than the J1772 contacts maximum temperature rise of 50 deg C, but not by much. Of course it would be of interest to see if using other 30a EVSEs in comparable charging sessions show similar contact temperature rises.

I am struck by the fact that (visually at least) the temperatures of the two contacts aren't more nearly the same for the RAV4 since the current passing through each should be the same. It would be interesting to see other tests to see if this difference is consistent or if it varies by, say, how the nozzle is inserted, etc.

Comparing car inlets, since the LEAF inlet appears to have more solid material between the 5 holes for the contacts than that of the RAV4, it might support the nozzle more securely, i.e. allow less flexing of the inlet plastic and so provide for better contact mating, i.e. lower resistance and so consistently less contact heating during charging.

I'm not saying the temperature rise is out of J1772 spec, but it is alarming. I did a test on my Leaf for about 5 minutes charging at 32 amps (over the limit by 2 amps), and since the test was a shorter duration it didn't get as hot, but I noticed the same disturbing heat bias on the left side. This, to me, indicates a probable fault in the Blink/Rema handle on the left side. I will perform some more tests as well as take apart the Rema handle and nose around. You are absolutely right, there should essentially be the same rise on both sides! A large difference like this, and seeing it on 2 different cars, means to me there is a fault in the Blink/Rema. Either it's poor contact/connector design, or a manufacturing fault, such as a bent socket or a bad crimp. I will get to the bottom of this!

I will also connect a different handle to both the Leaf and the Rav4 and run a thermograph.

-Phil

 

[Ingineer]

Anybody know what handles are used on the GE WattStation? Another possibility of the failures we've seen could be a due to poor connections. Might be worth a look.

-Phil

 

[DaveinOlyWA]

once again Phil, your info is invaluable...

Tony; go ahead and remove the "RAV 4" from the thread title

 

[Ingineer]

Are there two small holes in the plastic insulator under the AC power pins on that?
It is a bit hard to tell from the photos, but it almost looks like there is a cutout under each.
Could they have intended for moisture and other stuff to fall through into the center channel, but instead they let too much oxygen get into the hot area?

These are drain holes to allow moisture to roll out of the back of the connector. There is no attempt to keep oxygen out, as this would be futile.

The photo of the Roadster adapter looked like the plastic insulator fully enclosed the J1772 plug/pins. I wonder if they put holes back there to avoid having a pressure/vacuum form to make it easier to push the plug in and out?

No. There is no hermetic seal on the protrusions of J1772, so there would be no significant pressure delta. It's there for moisture.

-Phil

 

[Ingineer]

Here are a few more pics:

This one shows the rear of the inlet. This would be where you attach the thermostats for my failsafe modification. (to the orange cables as close to the inlet as possible.)

Here's the rear of the inlet after the pin retention basket and pins have been removed. You can see the drain slots:

Here's the bare pins and basket:

-Phil

 

[TonyWilliams]

TonyWilliams: I'm not sure where a common situation would occur where one would have charging at about 40 amps, since all currently commonly sold EVs in this country except Teslas seem to be limited to 30 amps and I believe the on-board charger determines the actual current draw.

The common situation for me is using 40 amps everyday at my house, as many / most Rav4's will be recharged.

The current draw is determined by both the onboard charger; 40 amps in Rav4, up to 70 amps in Tesla Roadster (operator selectable), up to 80 amps on Tesla Model S (operator selectable) and the EVSE. Most are indeed 30 amps. Some are 70 amps.

 

[MikeD]

TonyWilliams: I stand corrected about the Rav4 on-board charger -- it's 10kW so it can draw about 40a at 240v with a compatible EVSE that supports that amount of current. I will correct my previous post -- don't want to mislead readers.

BTW I did not mean to slight the Rav4 EV, but it is SO disappointing that a major seller of cars including hybrids has put forth such a limited EV effort, so much so that I must admit my research into its capabilities has been adversely affected and similarly limited. (From Wikipedia: "Production will be limited to 2,600 units during the first three years, and sales will be limited to California only, beginning with the San Francisco Bay Area, Los Angeles/Orange County and San Diego.")

If there are overheating issues with certain current makes of EVSEs independent of the EV being charged, adverse charging experiences with the 2013 LEAF 6.6kW on-board charger should quickly reveal them. But I expect Nissan for one has already been checking them out, as they actually have a vested interest in their EV's success.

 

[palmermd]

But I expect Nissan for one has already been checking them out, as they actually have a vested interest in their EV's success.

The only problem with this is that the Leaf currently does not draw enough current to make this problem apparent. Even with the new car at 6.6kW it will not be really apparent like Toyota or Tesla will see with 10kW and 20kW onboard chargers.

 

[TonyWilliams]

it is SO disappointing that a major seller of cars including hybrids has put forth such a limited EV effort

Repost from the official Rav4 thread:

I wonder if this is related to why Toyota only plans on 2600 units of Rav4 EV during the 1st 3 years.

Toyota wrote a $100 million check to Tesla for 2600 cars; $100 million divided by 2600 equals $38,461 per car, plus Toyota has to actually provide the car and assemble the Tesla provided bits in Ontario, Canada. The car retails for $49,900. Toyota loses about $10,000 per car sold, or about $26 million for the 2600 cars. It only cost this huge amount because they contracted Tesla, and it's a limited production run. Tesla isn't selling $57,000 Model S at a loss, which is virtually the same drive train in the Rav4.

They thought of the best way to meet their California zero emission mandate, and apparently this is it.

Read this tutorial:

http://www.arb.ca.gov/msprog/zevprog/factsheets/zev_tutorial.pdf" onclick="window.open(this.href);return false;

It will answer lots of questions. In a nutshell, if Toyota makes 0.79% of it production with ZEV's, that is one part of the overall compliance with CARB rules.

330,000 cars multiplied by 0.79% equals 2607 cars.

 

[JimLovewell]

Here are a few more pics:

This one shows the rear of the inlet. This would be where you attach the thermostats for my failsafe modification. (to the orange cables as close to the inlet as possible.)

Here's the rear of the inlet after the pin retention basket and pins have been removed. You can see the drain slots:

Here's the bare pins and basket:

-Phil

Phil, thanks for posting the photos. I really helps to see the Leaf connector in order to make the modification mention earlier.

Jim

 

[MikeD]

palmermd: Teslas and Rav4s cannot draw more than the current EVSE design limit of ~30a for Blinks and AeroVironments and others with that same limit (that limit is communicated to the charger from the EVSE via the J1772 protocols and it is mandatory that the charger observe that limit), so I think the 2013 Leaf whose new on-board charger is expected to be able to draw that same 30a should be sufficient.

The real issue it seems to me likely lies with whether the mating of the contacts is always sufficiently sound to ensure the required low electrical resistance (between the contacts) for low level heating that will not cause damage (such as melting) especially for charging sessions using the maximum current level of 30a.

It may be that Nissan's decision to initially include only a 3.3 kW on-board charger was in part a desire to be cautious and deal with any problems at that level before proceeding to the 6.6 kW level and any of its attendant problems.

 

[palmermd]

palmermd: Teslas and Rav4s cannot draw more than the current EVSE design limit of ~30a for Blinks and AeroVironments and others with that same limit (that limit is communicated to the charger from the EVSE via the J1772 protocols and it is mandatory that the charger observe that limit), so I think the 2013 Leaf whose new on-board charger is expected to be able to draw that same 30a should be sufficient.

The real issue it seems to me likely lies with whether the mating of the contacts is always sufficiently sound to ensure the required low electrical resistance (between the contacts) for low level heating that will not cause damage (such as melting) especially for charging sessions using the maximum current level of 30a.

It may be that Nissan's decision to initially include only a 3.3 kW on-board charger was in part a desire to be cautious and deal with any problems at that level before proceeding to the 6.6 kW level and any of its attendant problems.

That depends. The problem is with the handle that is on the Blink EVSE. If another manufacturer uses the same handle, then the problem can be transferred to an EVSE that has a higher current rating. If on the other hand this problem is because Blink decided to build their own handles and this problem is isolated to their units, then I agree.

All I know at this point is that I am very glad that I don't own a Blink EVSE and I'm glad that Blink is not doing any work in my area...not a single Blink within 100 miles of here.

 

[Nubo]

palmermd: Teslas and Rav4s cannot draw more than the current EVSE design limit of ~30a for Blinks and AeroVironments and others with that same limit (that limit is communicated to the charger from the EVSE via the J1772 protocols and it is mandatory that the charger observe that limit), so I think the 2013 Leaf whose new on-board charger is expected to be able to draw that same 30a should be sufficient.

The real issue it seems to me likely lies with whether the mating of the contacts is always sufficiently sound to ensure the required low electrical resistance (between the contacts) for low level heating that will not cause damage (such as melting) especially for charging sessions using the maximum current level of 30a.

It may be that Nissan's decision to initially include only a 3.3 kW on-board charger was in part a desire to be cautious and deal with any problems at that level before proceeding to the 6.6 kW level and any of its attendant problems.

Now with other BEV manufacturers coming (tentatively) onboard, we may be pleasantly surprised at all the things that Nissan did *right*

 

[Ingineer]

Ok, I've confirmed the problem is 100% on the Blink side. I constructed a J1772 extension using a brand-new 70A ITT inlet connected to a brand-new 70A handle. I then connected this to the same blink and then to the Rav4.

Here's a thermograph of the same Rav4 inlet after charging 60 minutes at 30A with the new handle: (Evenly balanced and only 88 degrees max)

Here's the new 70A inlet connected to the same Blink, not it looks almost the same as the Rav4 did in my first test!

Here's the Blink handle:

I think it's safe to say the Blink has a problem on one side. I will take it apart later for inspection.

-Phil

 

[palmermd]

Great work Phil. Thanks for all your efforts.

 

[DaveEV]

Great work Phil. Thanks for all your efforts.

+1.

Looks like an easy fix is to replace the Blink handle with an ITT handle (purchased from Leviton who has the best prices on them).

From the picture of the Blink connector, it almost looks like a bad connection to the pin with all the heat focused at the base of it... Seems way to coincidental that the Blink Phil had on hand happened to have the exact same issue as Tony's - this must be a wide-spread problem but I wonder why other EVs like the Active-E aren't also seeing the issue? Perhaps they also have a thermistor like the Fit-EV?

I bet Model-S / Roadster guys aren't seeing the issue because they either rarely charge on Blinks or because they use that hunky aluminum adapter to plug in...

 

[Ingineer]

Phil, thanks for posting the photos. I really helps to see the Leaf connector in order to make the modification mention earlier.

Jim

Jim, those pictures are of the Rav4's inlet. The Leaf is almost identical, but with smaller wiring.

-Phil