Ok, used a wrong word there, my fault... what I meant is Tesla likely wanted to reduce risks / safety concerns. Production defects are in a different category.
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HPWC plugged into 14-50 - is this ok?
- Thread starter Moderatefan
- Start date
ponzu
Member
I tried to keep up with the thread, but can someone summarize -- provided the consensus has been reached.
Modifying and plugging HPWC into NEMA 14-50 -- works on YouTube, but probably not legit either by Tesla's rules or code.
Plugging UMC overnight into NEMA 14-50 as the primary charging solution -- slower than HPWC, but legal and used by many. Is it safe? Or at least as safe as HPWC?
Did I get any of it right?
Modifying and plugging HPWC into NEMA 14-50 -- works on YouTube, but probably not legit either by Tesla's rules or code.
Plugging UMC overnight into NEMA 14-50 as the primary charging solution -- slower than HPWC, but legal and used by many. Is it safe? Or at least as safe as HPWC?
Did I get any of it right?
TT97
Active Member
A few months ago DÆrik received an HPWC with a NEMA 14-50 plug:
It was never really clear how he received it or if it is legit but could be an new HPWC Tesla is planning on releasing. There are also many EVSE on the market that plug into a 14-50 but you would need an adapter.
If you have a NEMA 14-50 outlet already and you want the HPWC, I would recommend getting an electrician to convert it to hardwire to a HPWC. I had a 50-amp circuit connected to my HPWC - it is a little less than the max you can charge the 3, however, I felt it was future-proof to that can be converted to an EVSE or NEMA 14-50 (also, I already had 50-amp free circuit on my existing panel)
ponzu
Member
I have nothing existing and after reading and asking am leaning towards having a NEMA 14-50 installed. Then in the short run I can use the included UMC provided I don't see any red flags as far as safety. In the long run, I can
- buy an extra UMC
- buy a HPWC with 14-50 plug -- if it materializes
- buy a full on HPWC and have the NEMA 14-50 converted
It's not that I 'want' a HPWC (I don't need a full charge every night), it's just that I thought it was the only approved option for home charging.
I saw the video embedded earlier and thought it was a joke. Didn't click it. Now that I did, looks very intriguing.
TT97
Active Member
If you go with a 14-50 using UMC - you really wouldn't need an extra UMC. You can just leave the UMC plugged in and only take it with you when you go on a trip. Even if you reduce the UMC to 24 amps - you would still charge at 22 miles/hr.
Not sure where you got that idea. The UMC is by far the most common way Model S and X owners charge at home, usually plugged into a NEMA14-50 outlet. The “mobile” in UMC is a capability, not a requirement.
The Tesla web page about home charging discusses both UMC and Wall Connector options, and mentions leaving the UMC plugged in and just taking it with you when going on a trip.
Home Charging Installation
- Extra risk from UMC comes from plug/unplug(could be unintentional pull) cycles - so if you have a loose connection, an overheating is possible, maybe meltdown. So, if you can minimize those plug/unplug cycles it will make it safer.
- HPWC has the benefit of extra charging capability, especially if you have multiple cars - then you can do wiring once for 100amp and split the circuit between multiple HPWCs. So, there is really no benefit of plugging $500 HPWC into 14-50. You're better off paying $300 for UMC. It is also safer compared to UMC plug/unplug.
- If you install 14-50 first and then decide to switch for HPWC, you may want to upgrade the wiring+breakers from 50amp to 60amp(1 car) or 100 amp(several cars). Otherwise, your HPWC will not give you the extra value it is capable of.
I would suggest there is a little bit of "meet me in the middle" between @Moderatefan and @TexasEV regarding the original Gen1 UMC. I am still on my very first original Gen1 UMC that I have had and used daily for over 4 years now and never had a bit of trouble with it. However, I did decide early on to not run it at the full 40A maximum rate all the time. I've been using it in the low to mid 30's, and it has been totally bulletproof reliable. I do believe it was a little underbuilt in a couple of ways to support running at maximum 40A all the time for extended periods.
Well, and if you run $500 gen1 appliance at the rate of $300 gen2 one, then there's really no benefit to paying $200 extra.
Please read what I wrote a little more carefully. You might want to become more familiar with heat cycling and thermal stress too. A gas car has a maximum RPM red line. You can use it occasionally, and it's fine, but if you try running the car at its red line 100% of the time , I guarantee you you are damaging and shortening the life of that engine, and probably various other related parts. The point is that you still get some benefit of a device having the capability of running at a more powerful level sometimes, even if you don't use it all the time. I have used my UMC to charge at 39 or 40A when traveling a few times, and it did fine and was helpful to shorten those stops when I was needing to wait for it to charge. But for 365 nights a year, every single night at home, that is subjecting the metals and solder joins and electronics to more extreme hot/cold/hot/cold cycles every single day for what purpose? So it can finish charging in 3 and a half hours instead of 4 when I am sleeping for 8 hours? That does nothing for me at all. But having the extra capacity to use sometimes when it is useful does have some value.
If the $300 device is built for a maximum 32A current level, it may have similar issues running at 32A all the time. Leaving a little margin from the maximum running rate of any piece of equipment is usually a little helpful to extending its life.
Does Tesla state anywhere in the manual that the UMC charger should not be run at the full capacity regularly or else?
I'm thinking that if it is properly designed, whatever the buffer is needed(?) should already be embedded. The comparison with the RPM may not be adequate, b/c the charger WILL be used at the full capacity most of the time and if that presented a problem, we'd be warned about it, similarly to everyone mentioning that electrical circuits should be run at 80% for continuous load. Charger is originally designed for continuous load.
No, there's nothing that says that.
I don't disagree. It should have been designed more robustly, because the expected recommended use is just to plug it in and let it do its thing, which would be running at maximum all the time, and it doesn't necessarily handle that well. I did specifically say in my earlier message that I thought it was a little underbuilt for what its rating is. I was just pointing out that it's not really fair to say it's unreliable for any kind of use at all. If you treat it a little softer, with slightly lower use most of the time and higher use occasionally, it can still be very very reliable and long lasting.
Besides, the 32A smaller version would obviously be scaled down in some of those parts, with smaller wires and connections, so it might or might not have the same issues with running at its maximum level all the time too, so it's not necessarily going to be perfect just because its rating level is a lower number.
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