Thanks to everyone for the clarification on "plug-in" HPWCs - may have to consider that approach for our MX.
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mknox
Well-Known Member
My only concern there is that oven 14-50 outlets are often wired with 40 amp breakers and #8 wire. That cord you purchased might have #8 conductors when you should really use #6 for a 40 amp continuous load. I'm assuming your 14-50 outlet has been wired with a 50 amp breaker and #6 wire.
Brass Guy
Active Member
Regarding the warranty, my paperwork from 2013 is clear that the UMC is covered under its own warranty which is one year. I think Tesla is replacing them under the new car warranty for those of us that purchased before the change. HPWC may be the same.
It does seem that they don't want cover the HPWCs that long anymore since the order change.
It does seem that they don't want cover the HPWCs that long anymore since the order change.
Just to be clear - it's perfectly legal and safe to run #8 in conduit at 40A charging (50A required circuit rating) and I wouldn't blink an eye if it were wired as such for permanent installs. If it's NM cable (Romex), it must be #6.
When you are talking flexible cord, there's a different table you have to use. NEC uses table 400.5, which requires #6 flexible cord for 55A with 2 current carrying conductors.
mknox
Well-Known Member
Right. Took a second look at the picture and it does show the 14-15 connected via conduit. It was really that stove cord I was concerned about. Products like these suggest they're rated for a 40 amp stove although don't show the conductor size. I've seen other stove cords (again, without specs) that say they're for 50 amp stoves and both have 14-50 plugs.
breser
AutoPilot Nostradamus
I never really understood how Tesla could deal with the warranty on the HPWC as being part of the car warranty. I bought my HPWC with my first car. I've sold that back to Tesla before I got my 85D. So how do we keep track of the mileage for the warranty? Is the warranty for the HPWC dependent on how many miles the new owner puts on the car?
I just searched - I swear the Tesla Gear store showed the warranty differentiation between the two order types, but I don't see that anymore. My SC recently verified that the warranty is 4 years when bought with the car. Who is telling you this isn't the case? Do you have documentation showing that you purchased it tied to your VIN and not with a CC separately?
Me again! I called Tesla Headquarters & they confirmed that back when I bought it, it WAS & IS covered under the 4 yr warranty. They said that policy is different now, but for early adopters, the warranty was different. So he will be calling my SC to inform them. Thanks everyone for the ideas & help.
That's awesome! I fall into the same category, so if I get push back I'll know what to do. Although my service center has never declined anything, they always bend over backwards to please.
S100D
Member
I just got my car on June 2, 2015 so I am reading the messages in TMC. I agree with earlier posts that it looks like the black wire in the HWPC was not tight enough and cause excess amps that caused the charger to fail.
Since I was worried about the HWPC failing and me not being able to charge my S85D, I installed a 14-50 receptacle with a 50 amp breaker along with the 100 amp breaker to handle the HWPC.
I just ordered the 2nd charger so I will be able to use 80 amps to charge my MS.
My HWPC in in the garage and I had thought about adding (drilling) some holes) on the top sides and the bottom of the charger to allow the heat to escape. I decided to not do that at least until the warranty expires in case the charger fails. Has anyone else considered doing this?
Since I was worried about the HWPC failing and me not being able to charge my S85D, I installed a 14-50 receptacle with a 50 amp breaker along with the 100 amp breaker to handle the HWPC.
I just ordered the 2nd charger so I will be able to use 80 amps to charge my MS.
My HWPC in in the garage and I had thought about adding (drilling) some holes) on the top sides and the bottom of the charger to allow the heat to escape. I decided to not do that at least until the warranty expires in case the charger fails. Has anyone else considered doing this?
I haven't had my car long, but am on my second HPWC. The first one installed fine and worked on all settings EXCEPT 80A. On 80A it would generate 8 red flashes when connected to the car or when using an external J1772 tester. On all other settings it worked fine. My analysis of the failure was too much capacitance in the pilot line and too high of impedance in the pilot drive circuit such that on the very narrow pulse width for the 80A pilot, the EVSE couldn't reliably detect the resistance due to rounding of the square wave.
Tesla promptly sent me a new one, which didn't have the same issue, so I'm happy with service. However the HPWC in my opinion, and I have specific experience designing EV charging systems, is not engineered as well as I think it should be.
For starters, the wiring, fuses and mechanical connections for the 80A current are barely adequate, and embody a lot of resistive losses, so this is why there is a lot of heat generated. Also, the contactor has a 240VDC coil, but Tesla took no steps to reduce coil current after pull in which is customarily done on other large contactors. In fact, the manufacturer of the ones they use in the battery pack sells models with built-in "economizer" circuits, here is the circuit that is built in that performs this function:
Doesn't cost much to add, and drastically reduces the heat in the contactor. What's more, is Tesla could have added the economizer function in the HPWC's firmware without the need to add any circuitry! It's often used in EV's to reduce the overhead so you save precious watt-hours instead of wasting them as heat in your coil. In the HPWC, this isn't as important, but the heat component is. Add the heat from both the resistance losses in the high-current path and the coil and you have one hot unit! This thermal cycling is not good for reliability and can hasten oxidation and the loosening of mechanical connections, which causes the problem to spiral out of control and then something burns out. This has happened to many HPWC users!
When I purchased my MS, I tried to purchase the HPWC with the car, and was told by my adviser to just login to my Tesla and order it on the web site. Problem is, they explicitly state "The standard warranty for the Wall Connector is 1 year for over the counter and aftermarket online purchases." There was no option for me to do anything else.
I love my MS, but I must say this is a chicken-**** move on Tesla's part. Clearly they are having a lot of warranty claims. It's also clear to even a layman that the unit gets overly hot, and most people know that heat is the enemy of electronics. I could care less about the warranty if it was superbly engineered, or at least engineered to standard automotive specs for a high-current appliance that is expected to be used daily. In my professional opinion it is not.
My solution is to modify (band-aid) the system as well as practical to ensure it is reliable. There's almost as nothing as frustrating as unreliable transportation, and the HPWC is an integral part of the car's operation.
There's a lot at risk to Tesla right now at this phase in their growth. You wouldn't think they'd be willing to gamble with something as critical and so full of latent liability as a high-power electrical appliance.
Tesla promptly sent me a new one, which didn't have the same issue, so I'm happy with service. However the HPWC in my opinion, and I have specific experience designing EV charging systems, is not engineered as well as I think it should be.
For starters, the wiring, fuses and mechanical connections for the 80A current are barely adequate, and embody a lot of resistive losses, so this is why there is a lot of heat generated. Also, the contactor has a 240VDC coil, but Tesla took no steps to reduce coil current after pull in which is customarily done on other large contactors. In fact, the manufacturer of the ones they use in the battery pack sells models with built-in "economizer" circuits, here is the circuit that is built in that performs this function:
Doesn't cost much to add, and drastically reduces the heat in the contactor. What's more, is Tesla could have added the economizer function in the HPWC's firmware without the need to add any circuitry! It's often used in EV's to reduce the overhead so you save precious watt-hours instead of wasting them as heat in your coil. In the HPWC, this isn't as important, but the heat component is. Add the heat from both the resistance losses in the high-current path and the coil and you have one hot unit! This thermal cycling is not good for reliability and can hasten oxidation and the loosening of mechanical connections, which causes the problem to spiral out of control and then something burns out. This has happened to many HPWC users!
When I purchased my MS, I tried to purchase the HPWC with the car, and was told by my adviser to just login to my Tesla and order it on the web site. Problem is, they explicitly state "The standard warranty for the Wall Connector is 1 year for over the counter and aftermarket online purchases." There was no option for me to do anything else.
I love my MS, but I must say this is a chicken-**** move on Tesla's part. Clearly they are having a lot of warranty claims. It's also clear to even a layman that the unit gets overly hot, and most people know that heat is the enemy of electronics. I could care less about the warranty if it was superbly engineered, or at least engineered to standard automotive specs for a high-current appliance that is expected to be used daily. In my professional opinion it is not.
My solution is to modify (band-aid) the system as well as practical to ensure it is reliable. There's almost as nothing as frustrating as unreliable transportation, and the HPWC is an integral part of the car's operation.
There's a lot at risk to Tesla right now at this phase in their growth. You wouldn't think they'd be willing to gamble with something as critical and so full of latent liability as a high-power electrical appliance.
It is no secret that Tesla's HPWC, and UMC are not engineered well enough to run at their full capacity, 20kw, amd 10kw, respectively. I have said this from the very beginning. You would think that such a crucial part of the cars functionality would be more reliable, and better engineered, but it's not. I have yet to have a UMC last a year(have been through 7 or 8). I don't see that changing, because the fixes have been patches that don't fully address the real issues. It's really painful and sad to watch.
rxlawdude
Active Member
Evan, I remember you from the early 2nd gen Prius days! Glad to be joining the Tesla community now.
Agreed. I don't want to drag this too far off topic, but Tesla really needs to step up, and soon, on these issues if they want to be better than other automakers and continue to hold on to their world-class image.
The 3 biggest things making me uneasy about my MS (and Tesla) are, in order:
1. The drive unit problems. What's going to happen after the warranty?
2. Tesla's failure to give owners basic service info and make parts available for reasonable prices (or at all)!
3. The 12V "Vampire" fiasco. Again, Am I to buy a 12V battery every 18 months and pay for all that wasted electricity?
I have a lot more than those, but those are the biggies. I'll stop now before I get too far OT.
1. The Drive Unit problems are probably not that big of a worry, as most of the issues are just noisy DU's due to very wide manufacturing and assembly tolerances. The drive units are also plentiful and cheap used, because Tesla is hostile to owners of salvage(and non-salvage for that matter) cars.
2. Working on the Model S is pretty easy for people experienced in that field. The big snag is getting parts, and access to firmware/diagnostic menu. This will change in time, as I can't see this monopoly lasting long.
3. The vampire load is due to connectivity/BMS. It doesn't have to be that way(Rav4 EV isn't), but it's a decision Tesla has made most likely due to information gathering(the car uploads the logs every couple of weeks).
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