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

[Ingineer]

If I understand this mod, when over temp it will act as if you pressed the trigger, causing the on-board charger to stop drawing current, but will not open the relays in the EVSE? Any worries about compromising weather resistance?

Yes, I chose this method specifically so the car can resume charging once cool. Having power present will not affect anything, and the EVSE will not see a disconnect. Disconnection via the pilot would violate the J1772 disconnection schema, and expose the relays to arc damage. This also ensures you will continue to charge even with a charge timer, whether EVSE based, or car based.

When you notice your car is taking longer then usual to charge, it's time for an inspection of the connections.

The only wire exposed to the weather by my procedure is the proximity line, which is low-voltage and low-current. Even if you didn't follow my instructions about properly sealing the connections, I suspect you would have no problems for the life of the car. Since you are not disrupting anything else, there should be no reduction in reliability.

-Phil

 

[TonyWilliams]

Here's a quick how-to: (WARNING: This may void warranties, set fire to your cat, and cause the end of the world. The whole time pissing off the lawyers, so DO NOT perform this modification unless you are FULLY QUALIFIED!)

I heard it may also cause cancer in the State of California.

Take out your J1772 inlet on your car, remove the weather boot, and ziptie one of the above thermostats to each of the two main AC wires

As always, thanks for sticking your neck out a little for all of us. This will go in the archives.

 

[DaveEV]

Nice job Phil! I knew you'd be able to whip this up in your sleep - and for < $20 in parts, too.

For those who don't want to hack up their car, you could build this into a short J1772 extension. You'd probably want to put the circuit on both the inlet and connector of the adapter.

FWIW the modular EV power guys posted some data from their testing of their aluminum inlet and saw these results after 5 hours of load on their 30A rated inlet.

30A 20F rise at center of insulator
45A 40F rise at center of insulator, 50F rise at pin
48A 47F rise at center of insulator, 52F rise at pin

I have no idea how J1772 is able to handle 75A. Temperature rise must be huge at the pins as the pins are the same size. It does look like ITT uses "HEP contact technology" on their 75A connector to improve the contact at the pins - Tesla uses something that looks similar for their new connector as well.

Personally if it was me - I'd opt to use a 75A rated connector/cable if possible when charging at 30A+. If nothing else it will be very slightly more efficient and I like overkill for things like this.

 

[surfingslovak]

Parked next to a Roadster the other day, and had a good look at the J1772 inlet on the adapter. I'm pretty confident that the inlet on the RAV4 was manufactured by ITT Cannon, and is nearly identical to what the Roadster is using, with the exception of the form factor and mount. In the light of this, it's very surprising to hear about the incident Tony reported, especially since these inlets are rated up to 75A and have apparently worked for many Tesla owners. Like the thermistor idea. Simple, effective, brilliant. Wonder why something like that was not incorporated into the J1772 standard.

 

[DaveEV]

The Tesla inlet is way different.

Different plastic, different pins.

 

[surfingslovak]

The Tesla inlet is way different.

Different plastic, different pins.

Really? Perhaps that's what they should have supplied to Toyota then. Tried and proven design.

 

[smkettner]

And here I thought all these were built to a set standard (same ampacity) and just limited by the cable attached.

 

[MikeD]

Ingineer: Why did you choose 70 deg. C?

The SAE J1772-2010 standard reads in part: "8.5.3 Temperature Rise -- The electrical contacts shall be designed for a maximum temperature rise of 50 deg. C above ambient at rated load. ... The wiring insulation shall be rated for 105 deg C."...

I am not saying there is a problem with your suggested fix, but I was not sure you were aware of this particular part of the J1772 standard and whether that might lead you to select a different temperature.

Because I am interested in Nissan's take on this potential charging problem, I inquired yesterday via Nissan LEAF Chat about this issue and mentioned the RAV4 incident behind it. I was told Nissan Technical Support would correspond with me further Monday, so maybe something useful will be forthcoming. I asked specifically if the 2013 LEAF had thermal protection for its J1772 inlet.

 

[surfingslovak]

It appears that this thread has reached a new level of notoriety:

 

[Ingineer]

Ingineer: Why did you choose 70 deg. C?

The materials in the connector and wiring will easily survive temperatures around this point without difficulty or damage. Keep in mind that a rapid rise to 100C at the contact point may not mean 100C at our thermostat sensing points, as there is plenty of thermal resistance and some mass to delay the response. In my experience, 70C will not "nuisance trip" and will still adequately protect all the materials even in the event of a fast rise condition. SAE spec is 50 degrees C over ambient AT THE CONTACTS, which means the contact should be of sufficiently low resistance to not allow more than this amount of rise. It does not mean that they are specifying the materials to endure that, obviously it will survive that and then some.

My take is that a detected temp of 70C through the insulation of the wire connecting to the contacts would actually mean a much higher temp at the contacts, and that it's a good compromise.

I wouldn't worry about this on the standard Leaf, as 16A isn't much to worry about. On the other EV's pulling more, such as mine with the 6.7kW upgrade (which pulls 32A), the Rav4, Focus EV, etc, this is a prudent bit of insurance.

-Phil

 

[TonyWilliams]

It appears that this thread has reached a new level of notoriety:

And the guys didn't meet with me, even though I was at the dealership while they were working on my car, and I asked to meet with them.

Oh well. Hi Toyota Engineering. I hope you put a thermal sensing device in your plugs (even if they came from Tesla) and thanks for bringing an R&D part for my car. They dropped the battery today and it should be ready soon.

The parts for Phil's overtemp mod are:

1 330WCT-ND RES 330 OHM 1W 5% METAL FILM 0.14000 $0.14
1 3M35-OR-ND TAPE ELECTRICAL VINYL 3/4"ORANGE 5.04000 $5.04
2 317-1000-ND THERMOSTAT 70 DEG C NC W/LEADS 6.56000 $13.12
Subtotal $18.30

 

[surfingslovak]

And the guys didn't meet with me, even though I was at the dealership while they were working on my car, and I asked to meet with them. Oh well. Hi Toyota Engineering.

Oh, hmm. I don't know if it's any consolation, but I assure you that they know you know that they know about their visits to this thread. How wonderfully meta is that? At least it sounds like you will have your car back soon, and it won't be out of commission for weeks while the dealership is waiting for the part. This is pretty much what happened to a number of ActiveE drivers, myself included. On an unrelated note, are you going to be at the OpenEVSE workshop tomorrow? I'm thinking of skipping that event.

 

[TonyWilliams]

On an unrelated note, are you going to be at the OpenEVSE workshop tomorrow? I'm thinking of skipping that event.

Yes, I will be there, but driving a Camry.

They did plug in my Rav4 twice today, as the EnTunes app reported, so we are close.

 

[TEG]

The Tesla inlet is way different.
Different plastic, different pins.

For reference, here is the (ITT) Tesla Roadster adapter on the left, and Tony's burned RAV4EV socket on the right:

 

[JimLovewell]

Do you have the same problem with all EVSEs? I had a no-charge problem only once ages ago - I found that I didn't fully insert the plug. Now I just make sure I fully insert the plug until it bottoms out and all is well - never had a repeat of the issue.

Like you, now that I know to pay attention to aliening the connector I am more carful but my wife and daughter are still having problems. Rather than being carful I see that they are just pushing on the connector harder. I am sure this will lead to more problems.
Because I want to avoid issues I am buying some connector gasket tools and keeping them with the car. I have also started inspecting public connectors before inserting.

 

[LEAFer]

The Tesla inlet is way different.
Different plastic, different pins.

For reference, here is the (ITT) Tesla Roadster adapter on the left, and Tony's burned RAV4EV socket on the right:

{ 2 images }

Thanks, TEG. Great idea. Now ... can anyone post photo of an undamaged RAV4 inlet ( in the middle between the two ) ?

 

[Ingineer]

Here's the Rav4 EV inlet (before burn):

Here's an IR thermograph of the external view of the Blink handle on the Rav4 after 2 hours of charging at 30A:

Here's the Blink/Rema handle-side J1772 connector: (137 degrees seems to be the hottest spot)

Here's the Rav4 J1772 inlet: (141 degrees. Note this one is getting hot on the opposite side as Tony's!)

For comparison, here's a Leaf inlet: (A paltry 75 degrees. Note that this one was only charging at 16A vs the Rav4's 30A)

I'll have to do a test of my Leaf charging at 30A and compare.

Here's the hottest thing I could find under the Rav4's hood after charging for 2 hours. Looks like the coolant pump:

-Phil

 

[waidy]

Good photos. Thanks for doing all these work. Our Rav4-EV has always been charged using the ChargePoint CT2100 and nothing else. I wonder what the temperature readouts are when charging it using ChargePoint station. We charged more than 4 hours, according to our ChargePoint record.

 

[DaveinOlyWA]

Great Pix Phil. wondering since you have a 6.6 KW charger on your LEAF what temps you see?

 

[TEG]

Here's the Rav4 EV inlet (before burn):

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?

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?