HPWC throttled back to 60 amps after v4.3 update

HPWC throttled back to 60 amps after v4.3 update

Got a message on the screen saying that the internal fuses on the HPWC will be upgraded at no cost to me by June 1st. Until then my HPWC is capped at 60 amps.

jat | April 3, 2013

So I guess they have been popping fuses at 80A. I have been waiting 3 months for my HPWC, so I wouldn't know :).

Peter7 | April 3, 2013

Hey Sunkat,

Did you happen to take a pic or can you bring this info back up?

Is it in the release notes?

Which version of 4.3 did you install? (.35 .40 .45 .??)

Is this a recommendation to reduce the charge current to 60A, or is the car now doing this for you? If so, can you override it and turn it back up?

Does it recognize that it is plugged into a HPWC vs. say a J1772 that supplies 80A?



biwamura | April 3, 2013

Just had the fuses replaced yesterday for the third time because of the inability to handle the 80amp charge. SC recommended to drop back down to 40 until the fix is completed.

sunkat | April 3, 2013

Peter7 -

The message was specific for HPWC. I was not able to over ride and am capped at 60 amps after 4.3 update.

The message linked to this page which came up in the car's browser:

more info there. I do not know if you can get 80 amps on non-HPWC charges, but great question...I am curious now too. I'm not aware of any of those near me or I would test it out.

sunkat | April 3, 2013

after re-reading the above linked website, looks like only HPWC capped at 60 amps. Super Chargers and others not capped.

skulleyb | April 3, 2013

I have not had one issue...
Wonder if I should skip the upgrade.

lolachampcar | April 3, 2013

Using OpenEVSE at 80 amps and loving the 2X charging. I too will be thinking twice about 4.3 if it can not tell the difference between HPWC and 1772 L2@80amp

sunkat | April 3, 2013

When I got home from work today and plugged into HPWC I was able to over ride the 60amp cap and set it back to 80; not sure why I thought I couldn't do it before; sorry for the mis-info!

So it's only a warning and reccomendation, you can over ride; don't let it stop you from updating to v4.3

sunkat | April 3, 2013

I"m going to leave mine at 60 amps though, just in case!

Alex K | April 3, 2013

@lolachampcar | APRIL 3, 2013: Using OpenEVSE at 80 amps and loving the 2X charging. I too will be thinking twice about 4.3 if it can not tell the difference between HPWC and 1772 L2@80amp

What J1772 cable/connector did you use to get 80A? I could only find the Leviton rated at 75A. I'm putting together an OpenEVSE for a second home since extra HPWCs are difficulty to get. I figured I'd try to run the Leviton at 80A and monitor the temperature. Can't see why an extra 5 amps would hurt - the cable at least can handle it.

Alex K | April 3, 2013

Forgot to mention that I'm running 4.3 (1.25.35) and there is no limit on the HPWC - I'm running at 80A and never had to increase it (from 60A). No blown fuses yet. Voltage drops down to 235V and current goes down to 79A after running a while.

sergiyz | April 3, 2013

same here, running 4.3, charging at 79A

Robert22 | April 3, 2013

Since they can't prevent the fluctuations in utility voltage, why not just mail out slightly higher capacity i.e. less sensitive fuses that can handle the flux variations? Any thoughts from the electrically inclined? This will likely push back delivery of HPWC's even further. It's impossible to order one at this time.

Peter7 | April 4, 2013

@Sunkat, Thanks for playing around with the settings!

@Robert22, I'm confused why they are blowing also, the datasheet shows that it takes more than 300A for 2 seconds to blow the fuse (TJN-100).... (


hammy16 | April 4, 2013

We were running at the 79 amp charge level since Early November and had our first fuse failure
a couple of weeks ago. Dialed back the HPC to limit at 70 amps since then until we see what

R3dStang66 | April 4, 2013

I wish they notified some people at solar city of this prior to having the hpwc installation.
I had my hpwc installed yesterday and everything looked good. It was charging about 58ish per hour. I checked my phone to check the status and saw that the charging had stopped. The front of the charging unit was very hot and the green light went dark. I called solar city and they did some investigating. They asked if i recieved an email about lowering the voltage to 60amps. I replied no and am now waiting for fuse replacements. The joys of being an early adopter =)

gasnomo | April 4, 2013

No problems here. Got and installed my HPWC a few weeks ago, always charges at 80A, no fuse pops...probably just jinxed myself...

pimp-boy | April 4, 2013

Ordered my HPWC on March 10th. Received it on the 2nd of April. Just installed it yesterday. Works great so far on a 80 amps draw. Never received any notice to not charge it at that rate. Running 4.2 software. Voltage drops to 231v @ 79 amps @ 55mi/hr.

gimp_dad | April 4, 2013

I have HPWC and v4.3 SW release and am not limited to 60A. Still charging at 80A. Not near my car so can't tell you exactly which v4.3 release I have but it was not the first wave of v4.3.

csamila | April 4, 2013


My name is Chris Samila and I am the Tesla account manager at SolarCity. Please email me at when you get a moment. I want to follow up with you about the fuse failure issue you experienced. We are working closely with Tesla Motors on this item.

If anyone else has any challenges please feel free to reach out to us at

Thank you,

Chris Samila

gimp_dad | April 4, 2013

Update to my earlier comment today. Just got another v4.3 update (old one was 1.25.40, new one is 1.25.45). Now the new one defaults to 60A when connected to my HPWC and if I attempt to increase the number above 60A it warns me about tripping the fuse.

I have been using my HPWC at 80A for four months now with zero issues. As a result, I decided to set it to 80A even with the warning (the warning just says it might trip the fuse needlessly and that it does not represent a danger).

Mark Z | April 8, 2013

@icsiyung: Highest charging rate with my HPWC was 54mi/hr, 236 V, 79 Amps. The electrician metered and checked the voltage and amp flow at the circuit breaker and it was higher, just over 80 amps at a higher voltage.

What really counts is the number of minutes it takes, and the "min remaining" seems to be about a mile a minute no matter what the charging rate shows. Will soon try a 50% or lower battery state of charge (SOC) to see if that makes any difference in the car or phone app readings.

Hopefully a future app version will allow overriding the scheduled charging after the initial charge is complete. To do a manual "top off" before a long drive requires a visit to the car to turn scheduled charging off..

LK | April 8, 2013

Interesting. I just completed wiring my home on saturday. I received the warning and continued to charge with 80a anyway. I'll report back and see If I have any issues.

lolachampcar | April 8, 2013

Alex K,
I too have the Leviton cable and am using it at 80 amps. I supply my OpenEVSE with 3 gage shore power cable which gets slightly warm after a few hours at 79 amps. The Leviton cable (also 3 gage) gets slightly warmer than the shore line cable which is no surprise given the quality of the shore power stuff. Neither temperature rise is anything to be remotely concerned about. For reference, I typically have 242V to start dropping to 238V @ 79 amps while charging.

I got a call from Ownership today regarding the HPWC related 60 amp limit in V4.3. I was told the car would use GPS position to remember last night's 80 amp current setting and that I would not need to adjust it again. He was partially right. The car did remember the current setting then promptly reverted to 60 amps when I plugged in. I have another email into Ownership to see if there is a way to shut this off or if I am going to have to manually answer the HPWC nag message every night and set the charge current to 80 amps. I'll post any useful response.

lolachampcar | April 8, 2013

gauge.... not gage
The American Wire Gauge Table rates -3 at 75 amps which is probably why Leviton rates their cables at 75 amps. I do not think 80 amps is going to be a problem in free air but then that is just my opinion.

Alex K | April 8, 2013

@lolachampcar | APRIL 8, 2013: The Leviton cable (also 3 gage) gets slightly warmer than the shore line cable which is no surprise given the quality of the shore power stuff.

I'm glad you are doing 80A on that cable/connector. I'll try the same when I receive mine. Actually, the Leviton cable is 6-gauge (at least that's how they spec it out). Unfortunately, they don't show it on their website any more. I have a screenshot from my browser history that shows the cable as "Cord type EVSE - 3 x 6AWG & 2 x 16AWG". For these cables, the insulation is what is critical for the rated amperage. For example, take a look at one of the largest manufacturers of EVSE cable, Philatron. Their 6AWG cable is rated for 99amps. I think the pins on the J1772 connector are also a deciding factor.

lolachampcar | April 9, 2013

Alex K
My bad.... -6 cable.

fmezz | April 14, 2013

I blew a fuse charging at 80 amps but I was running v4.2 software on my car so I'm wondering if it is really tied to version 4.3. Since then my car was upgraded to v4.3. Now I am taking the 60 amp recommendation and charging at that level.

jacob.gore | April 22, 2013

Are those fuses easy to replace? I wouldn't want to experiment with overriding to 80 and then require a house call from Solar City before I can charge my car again.

zero mpg | April 22, 2013

Given conduit constraints, I was only able to supply an 80amp breaker in the pannel and after configuring the HPWC for the breaker ... it would charge at 64amps. OE said the car charges at 20 percent of the breaker. So on a 6-50, you get 40amps and on the 80 you get 64 ... ok. After one of the 4.3 upgrades, i noticed that it is charging at 60 not 64. Will need to investigate this although not an issue as the car charges in 2 hours at 2am anyway. Just thought I'd share...

LK | April 22, 2013

Well, it's been a few weeks and charging at a full 80amps setting yielded positive results every time. I have not had any blown fuses and no issues whatsoever. I'm starting to suspect that an issue could be with how the install process was completed of certain chargers.

Again, no issues on my end.

Divesh | April 22, 2013

I am rmodeling my house including the Garage. I having wiring into 00the garage for 100 Amps. I was able to find NEMA 14-50 at Home Depot. I couldn't find the NEMA 6-50 outlet. Where can we these outlets. I told my electrician to install both 14-50 and 6-50 side by side. 6-50 if for future use when we have HPWC.

Captain_Zap | April 24, 2013

If you have twin chargers and have the opportunity to use a Roadster HPC 70A charger by using the Roadster HPC to Model S adapter, the car will now start charging at 60A and ask you if you are plugged into a Model S HPWC.

You can acknowledge the message and crank up the charging rate to 70A for the Roadster HPC. (There are some Roadster HPCs out in the wild in some areas along routes between major cities and they can come in handy if you have the Roadster HPC to Model S adapter.)

I had v.4.3 (1.25.35) before my update to 4.4 and I didn’t get the HPWC fuse advisory until I did the 4.4 update. I called Tesla OE and verified that it is ok to crank up the charging to 70A when using the Roadster HPC. Tesla mentioned that it is working on an update for the HPWC fuse situation. Once we get the update, HPWC charging will no longer be automatically lowered to 60A.

Warkovision | August 6, 2013

I picked up my MS on Saturday and this use only 60 Amps with the HPWC 17" screen warning is still in effect (for me anyway) even in the current OS - 4.5 (1.33.61) and I believe it is resetting my charge rate to 60 Amps on my evening 12:30 AM recharge. I also have the "C" updated version of the HPWC with the new fuses. I got in the car this morning with the 60 Amp advisory notice on the screen so I experimented. I increased the charge to 85% from my usual 80, adjusted the amperage to 80 and pushed charge. Everything seemed to be fine with the display indicating 79 amps, fluctuating between 227 and 228 volts, and 54 mi/hr and it added maybe 20 miles in a half hour. Will the current software always reduce the programmed early morning charge to 60 amps? It's not like it's monumentally important or anything given the amount of time at night I can charge but I was just curious.

mrspaghetti | August 6, 2013

Please post back and let us know after your next scheduled charge.

gimp_dad | August 6, 2013

Yes. It will require you to override the 60A setting each and every time. I have the latest HPWC as well and the SW in the car still has this "feature" even though there is no issue with the "C" version of the HPWC. I assume they will fix this soon in an OS release so that when you set the charge rate to 80A and you have the "C" version of HPWC and you have twin chargers it will remember and keep the 80A setting just like it used to in the early days.

Out of convenience I just force it to 80A when I know I want the extra charge rate for a specific need.

christurbeville | August 6, 2013

I was doing this same thing forcing it to 80 as I had a new HPWC. Well I guess it got hot enough or something because the fuses blew. They put back the 100A fuses as the 200A ones are in short supply so I stick to 60A for now.

ironmikeii | September 8, 2013

I'm charging at home with the HPWC at 80 amps for 5 days and have no problems. I was topping of the charge to100% for a trip and when I went to disconnect the cable, it was quite hot (cable & handle). What is the operating tempature at 80 amp charge rate?