Model S - HPWC (High Power Wall Connector)

[Andyw2100]

Thanks for the very detailed response, FlasherZ. I won't pretend to understand the math and the formulae, but I do understand how trivial the savings are! I still feel good about having used the best wire possible, since I wasn't going with the better wire to try to save money on the actual charging, but rather to try to avoid potential problems down the road.

Thanks again!

 

[Cottonwood]

For argument's sake let's say that I had used #3 cable instead and I was now seeing 234 W while charging instead of 237. Am I correct that if the car needs to charge the same amount in both examples, and if I'm charging at the same amperage, it is going to need to charge longer when it is only receiving the 234 W than when it is receiving 237, and since I am paying for the 240 I am drawing at the source in both cases, longer is, of course, more expensive?

Assuming all of the above is correct (which may be a big assumption, given my very limited understanding of this stuff) am I also correct that the fact that I generally charge at 56 amps will minimize but not eliminate the cost benefit I am seeing from lower voltage drop due to having installed better wire? Or does the lower amperage not factor in at all because the total amount of juice that has to get into the battery remains the same, and the speed at which it happens is irrelevant with respect to the loss?

As FlasherZ points out, the actual power differences are vary small between #2 and #3 wiring. The biggest reason to use #2 is availability. In both my installs, #2 was available immediately, and #3 was a several day order.

The suggested reason for lowering current to something like 56 Amps from 80 Amps for regular charging is to cut resistive losses in half. For copper, terminals, etc up to code, this is not a big deal, but for electronics (like the charger itself), semiconductor failure is exponential with temperature. Cutting resistive losses in half, cuts temperature rises in half, reducing the probability of failure.

As to total power saved in the resistive parts (very small anyway), the resistive loss is reduced as the square of current reduction, but the time increases linearly. The combination is that total energy saved is reduced by the same ratio as current reduction. Reduce power by 30% (70% of original), and the power is reduced by 50%, and the total resistive energy dissipated is reduced by 30%.

Finally, I don't think that you can install a 100 Amp breaker with #2 Aluminum wire. If there was a long run, to use AL wire on a 100 Amp circuit and connect to the HPWC, then the install would probably need a junction box near the HPWC to transition down from #1 or 1/0 AL to #3 Cu.

 

[Andyw2100]

Finally, I don't think that you can install a 100 Amp breaker with #2 Aluminum wire. If there was a long run, to use AL wire on a 100 Amp circuit and connect to the HPWC, then the install would probably need a junction box near the HPWC to transition down from #1 or 1/0 AL to #3 Cu.

Thanks, Cottonwood.

Yes, I think the electricians that were talking about aluminum were talking about using larger than #2 aluminum, and using a junction box. To be honest, I didn't pay too much attention to the details because I knew I was going to go with copper, and not be convinced to go with something else just because it was going to be easier for the electricians, none of whom had experience with a Tesla HPWC.

 

[omega]

Thanks, Cottonwood.

Yes, I think the electricians that were talking about aluminum were talking about using larger than #2 aluminum, and using a junction box. To be honest, I didn't pay too much attention to the details because I knew I was going to go with copper, and not be convinced to go with something else just because it was going to be easier for the electricians, none of whom had experience with a Tesla HPWC.

ok with all these being said and knowing that the garage side where the HPWC is getting installed is right above the area in the basement where the electric panel is what will they use (Al, Copper #1 #2 #3) ? For best performance.

Thanks!

 

[FlasherZ]

ok with all these being said and knowing that the garage side where the HPWC is getting installed is right above the area in the basement where the electric panel is what will they use (Al, Copper #1 #2 #3) ? For best performance.

Thanks!

If you're right above the panel, there is no reason they shouldn't use copper conductors; if they have #3 on the truck and/or easily available, they'll likely use it. If they don't, they typically have #2 on the truck and will use it, it isn't that much of a difference for that short of a run. There's really no sense to use AL for that short of a run because the price difference is minimal and using copper only avoids the need to use a J-box near or behind the HPWC to connect the #1 AL that's required to the #2 copper required to fit in the WC terminals.

 

[omega]

If you're right above the panel, there is no reason they shouldn't use copper conductors; if they have #3 on the truck and/or easily available, they'll likely use it. If they don't, they typically have #2 on the truck and will use it, it isn't that much of a difference for that short of a run. There's really no sense to use AL for that short of a run because the price difference is minimal and using copper only avoids the need to use a J-box near or behind the HPWC to connect the #1 AL that's required to the #2 copper required to fit in the WC terminals.

Thank you All!

 

[Chris]

Recently I had an issue with my HPWC, specifically with the handle. I noticed that plugging in took a little more effort than usual. One side of the handle looked like it had slightly melted#

.
One of the pins looked affected, as did the plug itself:

Charging still worked fine but I was concerned this might become an issue. When charging with 80A the handle always became very hot, which I considered normal. I brought this to my local service center's attention and they acted very quickly. Brought the car in, replaced the entire charging port and had an electrician come out to replace the HPWC cable and handle. No issues ever since. The guys at Rockville service center rock! Will be interesting to see if the new handle stays cooler.

 

[FlasherZ]

I've had my HPWC cable replaced twice over 2 1/2 years because it was getting hotter than usual. What you show is what likely happens over a long period of time as the contacts become dirty.

I imagine I could have cleaned the contacts with an appropriate brush and solvent and eliminated the heat, but as Tesla was out here anyway, they replaced it for me.

 

[Lloyd]

I've had my HPWC cable replaced twice over 2 1/2 years because it was getting hotter than usual. What you show is what likely happens over a long period of time as the contacts become dirty.

I imagine I could have cleaned the contacts with an appropriate brush and solvent and eliminated the heat, but as Tesla was out here anyway, they replaced it for me.

This should be a part of the annual inspection of the vehicles performed by Tesla !

1. Inspect the charge port and clean the contacts.
2. If the above is found then replace the chargeport in the car and find the corresponding HPWC and replace that cord as well!
3. Recommend annual or sooner cleaning procedures for all HPWC owners

 

[Peter_M]

Tesla has replaced my HPWC cable twice, not for overheating but for developing a "flaky" connection with the car. Pushing the handle to the right or left when it was plugged in would make it connect or disconnect. Maybe if I hadn't had it fixed quickly, the overheating would have started...

 

[FlasherZ]

This should be a part of the annual inspection of the vehicles performed by Tesla !

1. Inspect the charge port and clean the contacts.
2. If the above is found then replace the chargeport in the car and find the corresponding HPWC and replace that cord as well!
3. Recommend annual or sooner cleaning procedures for all HPWC owners

During my yearly service last week, they did inspect the HPWC and ensure that it charged - but that was because they came to me as part of ranger service.

That said, both times (for me at least), the dirty contacts were in the car coupling on the HPWC cord, so if my car went to them, they wouldn't be able to inspect it. Replacing my cord set on the HPWC made it get much cooler, so I doubt inspection of the charge port on the car would have revealed anything. (Of course, if it progressed to the melting point seen above, they would.) I suppose they could have the porters do it, but it would only work where the car was collected / delivered to their home address.

I think it might be as simple as a small bottle of solvent and a disposable brush of some type.

 

[Lloyd]

I use and carry with me Electrical Contact Cleaner spray.

http://www.amazon.com/WD-40-Specialist-Electrical-Contact-Cleaner/dp/B00CMT9TFY/ref=sr_1_4?ie=UTF8&qid=1427753419&sr=8-4&keywords=contact+cleaner

Not to be confused with regular WD-40

 

[FlasherZ]

Too bad the global warming nuts banned the good stuff that really works well.

(Yes, tongue-in-cheek humor for those of you who might not be able to detect it. In the 1980's, we had some really great contact cleaners based on 1,1,2-Trichloro-1,2,2-trifluoroethane [CFC-113], and since then, their effectiveness has been greatly reduced because there was a hole in our atmosphere above Australia or something.)

 

[hcsharp]

...When charging with 80A the handle always became very hot, which I considered normal. ...

Can you clarify - did the connector (handle) always get so hot that you couldn't touch it? Did it do this right from the start when you first got your HPWC? Did it do it from the start and get progressively worse?

Those contacts are rated for very high amperage - the sleeves likely at least 250A and the pins at least 325A. I'm wondering if you didn't have another problem like a bad crimp or weld. They would have to be awfully dirty to generate that much heat. Is it installed in your garage? Thanks for reporting this.

 

[pgiralt]

I've had my HPWC cable replaced twice over 2 1/2 years because it was getting hotter than usual. What you show is what likely happens over a long period of time as the contacts become dirty.

I imagine I could have cleaned the contacts with an appropriate brush and solvent and eliminated the heat, but as Tesla was out here anyway, they replaced it for me.

I've also had my HPWC cable replaced twice for getting too hot. The latest one has been working great, so hopefully there was some change made. Both times the hottest area was just where the handle connects to the cable.

 

[Chris]

Can you clarify - did the connector (handle) always get so hot that you couldn't touch it? Did it do this right from the start when you first got your HPWC? Did it do it from the start and get progressively worse?

The handle got uncomfortably hot towards the end of an 80A charge, but still ok to be unplugged. I am under the impression this became progressively worse over time. HPWC is installed in my garage and it's an early 2012 model. Never noticed any dirt on the pins but maybe this would not be visible to the naked eye

 

[Mayhemm]

This should be a part of the annual inspection of the vehicles performed by Tesla !

3. Recommend annual or sooner cleaning procedures for all HPWC owners

My HPWC is only hooked to 56A. Is this still something I should be concerned with, or is it mainly for full 80A connections? I'm coming up on the 1-year anniversary of my installation next month.

 

[Chris]

My HPWC is only hooked to 56A. Is this still something I should be concerned with, or is it mainly for full 80A connections? I'm coming up on the 1-year anniversary of my installation next month.

I was surprised to read that other owners had their HPWC cables replaced as well, sometimes more than once. It still is probably a rare issue and I would say if your handle is not getting hot and the pins looks clean you should be fine.

 

[FlasherZ]

My HPWC is only hooked to 56A. Is this still something I should be concerned with, or is it mainly for full 80A connections? I'm coming up on the 1-year anniversary of my installation next month.

Heat dissipated is the square of the current times resistance, so while 56A is 70% of the charging rate of 80A, heat dissipation across contacts and such is only 49% vs. 80A.

In my case, the handle was nearly too hot to touch after a couple of hours of charging.

 

[hiroshiy]

As a data point my HPWC cable gets warm at 80A but not hot at all. Maybe my voltage is 200V, not 240V.

BTW recently my Tesla only charges at 71A rather than full 80A, and I asked Tesla to check the logs. I thought my circuit's internal resistance or transformer capacity caused some voltage drop, but the engineer told me that my car's one phase of dual chargers is broken hence 71A. They offered me to change the on-board charger unit but I didn't ask because it's a minor issue.

However I thought "a phase is broken" seemed a little bit odd, since my circuit is 200V single phase, not three phase.