Slashdot Mirror
Tesla Sending New Wall-Charger Adapters After Garage Fire
JoeyRox writes "Tesla is sending its customers new home charging connectors after recent reports of chargers overheating in garages and one instance of a fire inside a wall socket that held one of the chargers. Tesla CEO Elon Musk said the new charging adapter will contain a thermal fuse capable of terminating the charging process if it gets too hot. 'These are very rare events, but occasionally the wiring isn't done right. We want people to have absolute comfort, so we're going to be providing them with an upgraded adapter.' The company also issued a software update in December to address the overheating issue."
I'll get in before the nutjob Tesla detractors.
This is a very responsible move by Tesla which takes guts. They are changing the charger design to ameliorate a problem that has nothing to do with the car and nothing to do with the charger and everything to do with the house wiring. Obviously the nutjobs will point their skinny little fingers and accuse Tesla of papering over their own flaw, which is a lie.
Tesla cars are really expensive, but they keep doing things like this. "Worried about the battery catching on fire? Okay, we will insure you against that for no additional charge. Worried about your garage charger catching on fire? Okay, we will give you an upgraded charger for free."
Anyone with a Tesla car is an early adopter, and paying a lot for the privilege. But Tesla really is doing their part to take care of the early adopter customers.
And this is why their overall strategy is brilliant. Start at the high end of the market, make money while building technology and infrastructure, and then come out with a new-gen car that costs less. Meanwhile they have fewer customers to take care of when issues like this pop up, and they have the money to just deal with it.
I can't wait until Tesla hits the Ford/Honda price level.
lf(1): it's like ls(1) but sorts filenames by extension, tersely
This is a 100% serious reply - Once upon a time, software developers selected beta testers, who used the software with the understanding that it was still in a beta version and bugs should be expected and documented.
Now, no such "testing" occurs in both the software and hardware realms. The developers or manufacturers simply develop something that compiles or doesn't collapse under its own weight and sells it as the release version to customers that expect all that testing to have been done already, so it works. Customers pay full price, the shit crashes or falls apart(or catches fire), they complain to the company describing what happened, and then the company documents what happened and gives the customer a "new" but equally faulty piece in exchange.
There is no more "beta" testing - the beta testers are now referred to as "early adopters."
-- Ethanol-fueled
Maybe nothing was really wrong. Maybe the wiring sucks, the charger draws too much RMS power due to a dirty wave (Fattened with harmonics), the excess current causes overheating, etc. So rather than putting in a current detector or whatever else to detect faults, he just ... stuck in a thermal fuse. If it gets too hot, it shuts off.
Most hardware doesn't constantly draw that much power. It's really hard to screw up a transformer--the wall charger would just be a transformer and maybe a MOSFET-based rectifier or something else that can pass that much power. Thermal fuse--even a current fuse--is really a "this will never happen, but if anything does happen that creates any kind of bad situation, this will stop it. Whatever it is."
Support my political activism on Patreon.
Older houses from the mid 20th century may have aluminum wiring, which turned out to be a really bad idea. They tried it because the cost of copper was going up and the cost of aluminum was going down, but it turns out that the properties of the two metals are different and the aluminum wires performed really poorly over time.
Occasionally living proof of the Ballmer peak.
There is a man, lets call him Keith. Keith thinks that repair men and contractors are overpriced, and decides he can do it himself. He does this, and it works...for now.
People haven't stopped beta testing. Either in hardware or software. They have been quicker to release because the vast majority of software nowadays are done inside a sandbox (mobile apps, cloud servers, etc) rather than from scratch.
It's not like software or hardware back then was any more reliable. Office, OS9, Windows (all versions) have always been plagued with problems and one can argue they have fewer obvious bugs now than they did before - When's the last time you got a BSOD?
The counterbalance is that the consumer base is far far far larger now. Some of us who were at Intel at the height of the Pentium 4 were happy to have sold 40M units in a year. Mobile phone processors at qualcomm nowadays clear 400M/quarter.
If it seems like hardware and software bugs show up faster, it is because the userbase that uses and report such bugs (easy to do now via social media) is much much much larger.
My 20A appliance loop in the kitchen has 15A receptacles because, heyyyyyyy, you're not really going to draw 20A out of these right? Those 2000 watt appliances don't go on a 20A loop that can pass 2200 watts... I use a Breville 1800W toaster oven drawing over 16A through one receptacle. One 15A receptacle on 20A wiring.
Most 15A receptacles are rated for 20A pass-through, so they should be perfectly fine to use on a 20A line. The only time you should need a 20A receptacle is if you have a single device with a 20A T-shape plug.
Because he wants to put his customers' minds at ease? It's a smart move on the part of the company.
Only two things are infinite, the universe and human stupidity, and I'm not entirely sure about the universe - Einstein
Alternatively... it could be exactly as he said, the car was not fire prone (as borne out by the stats showing it had lower fire rates than other cars, and better outcomes when they did happen), and that the fire department agree that it was not caused by the charger.
Instead, it could simply be that even though they're working fine, there's way to mitigate the risk of other faulty things causing problems, and it's nice to do something towards that.
Honestly, I hate this aspect of the modern world –no one is allowed to improve something without implying that something was broken before hand, or that it was their fault that something else was broken.
I was going to say, it's entirely possible the wiring in the wall was bad.
This is one possible scenario which has happened in the past. Maybe it was aluminum wiring, which has a much lower thermal expansion rate than copper. Back in the 70's it was really common for developers to use aluminum wiring in houses because it was cheaper than copper. My house had aluminum wiring. The previous owners of my house were really underhanded. They ran copper off the electrical box up in behind some insulation and connected it to the aluminum from junction hidden junction boxes, and because home inspectors don't do "destructive" inspections, meaning they don't even move insulation, we didn't find out until years after we had bought the house. We had a wall socket stop working and when I opened it up to see what was wrong I found the aluminum wire had completely detached from the terminals. Luckily my father-in-law, who doesn't live near by, is an electrician because we had to have the whole house rewired. It's still not illegal to use aluminum wiring, copper is recommended, but it's not requried. The higher temperature of the adapter could cause the aluminum wire to expand and pop off the plug terminals in the wall box, which can lead to arcing and fires.
It really wouldn't be Tesla's fault if developers were using cheap materials when building the house, but it is nice of them to do something to try and mitigate future issues after it becomes a known possibility. We can't account for every scenario that will ever occur, but we can learn as we go along.
The math has been done in every previous thread. The fire rate for Teslas is something like 5x lower than normal cars -- but we'll see if that changes once they age.
There have been a number of problems with the UMC (cable in question). The cable has an adapter on the end to choose from a variety of plugs, i.e. NUMA 14-50, NUMA 14-30 standard 120v, NEMA 10-30, 6-50, etc.
I myself have seen issues where my NEMA 14-30 adapter would give a fault if the cable was bumped. The connection between the adapter and the cable is not all that solid and a number of owners have had issues with this.
About a foot away from this connector is a control box that contains a GFI and a relay and the circuitry to interface to the car.
The adapter has 5 pins on it. One for ground, one for each 240V leg (neutral is not used) and a pin that appears to go to a resistor to signal the amount of current supported by the adapter. I don't remember what the last pin does. Anyway, for the amount of current the NEMA 14-50 and 6-50 adapters carry the pins are rather small. The adapter also doesn't always securely latch to the cable which can lead to a bad connection causing the adapter and/or cable to melt.
I don't think this will be a big setback for Tesla. Tesla's retail price for this cable is $600.
This post is encrypted twice with ROT-13. Documenting or attempting to crack this encryption is illegal.
I own a Tesla model S and was never very fond of how the adapters connect to the UMC cable. The UMC cable has a 5-pin connector on the end that plugs into the wall where it plugs into one of numerous adapters. The adapters contain pins for ground and the two 240V legs (not neutral) or the hot, neutral and ground for the 115V adapters. There's also a resistor in it that signals the amount of current that can be drawn between one of the pins and ground. I don't recall what the last pin is for.
The connector between the adapter and the cable is a weak link. I myself have had intermittent issues with my NEMA 14-30 adapter and the cable where just wiggling it causes a fault to show up. The adapter connector is not all that tight nor is it particularly secure. The pins are also rather small considering how much current they can be carrying (up to 40A).
A number of owners have reported that this connection between the UMC cable and the plug adapter has overheated or melted. While it sounds like in the case of the garage fire it was likely the fault of substandard wiring of the NEMA 14-50 outlet the UMC cables have been a known problem.
About a foot from this adapter cable is a small box that has a relay, GFI and some signalling circuitry to interface with the Model S.
I've only used the NEMA 14-50 adapter a couple of times since I have a separate high power wall connector that's hard-wired into my home (100A feed). I'm a lot more comfortable using that over the UMC cable but Tesla has to fix the early HPWCs as well. The resettable fuses are too sensitive so they recommend not charging at the full 80A. I myself have not had any problems at 80A but normally they reduce it to 60 until they send someone out to replace the fuses.
I don't think this will be a major setback for Tesla. The retail price of the UMC is $600 which means it probably costs a lot less to manufacture. I just hope that if they change that connector that they replace all of my adapters since I bought a number of additional ones (at $45 each) to handle NEMA 14-30, 10-30, 6-50 and 120v/20A.
The UMC is basically the equivalent of a normal J1772 EV charger but with a switchable plug and in a much smaller form factor. Hell, my HPWC charger is a fraction the size of most J1772 EV chargers yet it handles a lot more power than most J1772 adapters (and it doesn't even get warm when pumping 80A through it).
The UMC is nice since it means I can charge my car at any RV park that has a 240V hookup or that an owner just needs to install a NEMA 14-50 outlet which is a lot less expensive than either a high-power wall connector ($1200) or a standard EV charger.
This post is encrypted twice with ROT-13. Documenting or attempting to crack this encryption is illegal.
Sure. But. Calculations are still required for amp draw per circuit (which determines wire size and breaker ampacity), particularly when a specialty appliance has the unique demands of an electric car charger.
Not really any math above addition, and possibly even that if they're running a dedicated circuit for the specialty appliance like they're supposed to. The electrician memorizes some figures/looks at a chart. Heck, I've seen the figures printed on the boxes.
NEMA 5-15(standard outlet): 14 gauge minimum(copper), 15A* max, 12A design
NEMA 5-20(has the notch): 12 gauge minumum, 20A max, 16A design
NEMA 14-30(dryer, 240V): 10 gauge, 30A max, 24A design
NEMA 14-50(range, 240V): 6 gauge, 50A max, 40A design.
The 'formula' for simple installs is easy: Look at the amperage of the product you're using. round UP to the next breaker size. Use specified wire gauge. Manufacturers tend to make this even easier because they tend to not produce appliances that are close enough in amp ratings that you'd need to skip the next largest breaker - IE they don't make appliances that use 'exactly' 30A, they'll produce a <24A model then if you need heavier duty a 32-40A one.
Though I'll note that space heaters and hair dryers today tend to assume that you have a 20A circuit, but there's reasons why the heaters are limited to 1500 watts and dryers to 1875(but they're only this powerful if you feed them 125V, nice advertising guys! In reality they'll be closer to 1.6kw in homes with proper voltage).
*Though to meet code it has to be manufactured to be capable of safe operation at 20A+
I don't read AC A human right
It is also worth mentioning, with all this Tesla fire hype: Recalling parts for safety reasons in the automotive industry is the rule not the exception. Almost every model from every car manufacturer has had some parts or systems recalled. Fire is the cause of a significant percentage of recalls. It is hard to get exact numbers as each country has it's own database. I looked at the US one quickly for an example. Selected a random model and year (Aluma 2009), and sure enough there were three recalls for that year alone. The first one i clicked had the text "THIS DEFECT COULD RESULT IN A FIRE.".
Given the percentage of the vehicle fleet that is made of Teslas, this is not really relevant news.