HPWC Manual said:
I think it's clear that it'll split them. Prioritization, is a different matter. Maybe a simple FIFO system?
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New Wall Connector :)
- Thread starter pluginx007
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I think it's clear that it'll split them. Prioritization, is a different matter. Maybe a simple FIFO system?
SomeJoe7777
Marginally-Known Member
If that's the case that it's a bus, that's good, it means you can indeed turn off a unit in the middle of the chain and other units can still operate.
This might be a good capability in a commercial environment such as destination charging. If a plug or cable is damaged on one unit, that unit can be turned off and the other 3 can still operate until such time as the replacement/repair can be done. But when actually working on the unit where the communication wires may have to be disconnected will at minimum require any downstream slaves to be turned off as well.
You're right, I wouldn't worry about the low voltage communication power either, but some organizations are strict in their procedures such that all incoming power to a unit must be turned off prior to work, including low voltage.
Looking for some help here guys.
I got the new wall connector and I was going to install it along with a separate NEMA 14-50 as we will have multiple Tesla vehicles. But now I'm thinking that maybe I should just get 2 wall connectors?
I don't like this "load sharing" thing on one breaker. Wouldn't the charging speed be significantly less if 2 wall connectors are sharing one breaker? So perhaps install them on 2 separate breakers?
I got the new wall connector and I was going to install it along with a separate NEMA 14-50 as we will have multiple Tesla vehicles. But now I'm thinking that maybe I should just get 2 wall connectors?
I don't like this "load sharing" thing on one breaker. Wouldn't the charging speed be significantly less if 2 wall connectors are sharing one breaker? So perhaps install them on 2 separate breakers?
K-MTG
Sunshade Captain of TMC
Reviewing everything here, it looks like they need to be installed on two breakers.
But the advantage is that you could run a 100 amp sub panel and put in two (or 4) 100 amp circuits in that panel. If both were using it, the power would be shared. If ine was using it, it would get all the juice. Or if you don't have the capacity in the mains, 80 or 60 could be used.
If you put in multiple 14-50, they would be limited to 40a each. Even if only one was being used.
Thinking about it more, the advantage is even greater if one only had 50a spare in their main panel.
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Two wall connectors on two separate breakers would be better, only when both cars have very low SOCs, charging at the same time, and you need them both to finish fast. In most cases having the Wall Connectors allocate Amps based on SOC is going to work great.
You can always use timed start to force the higher SOC car to get a full charge first.
I do wonder how the Amps get allocated if the lower SOC car has a low limit charge rate (20 Amps) set?
I also think with getting multiple Teslas and using the new Wall Connectors I'm more likely to get the High Amperage Charger Upgrade so that when one car is charging it can get more of a charge before the second cat plugs in.
As I understand, the car will draw a maximum of 20A and the remainder of the HPWC's will offer the remaining current to another car. That said, I'm not operating on empirical evidence, just on what I've been told at this point.
Ulmo
Active Member
Is that possible today, with the in-car charging time start settings? Of course, estimating the readiness time would be better if wholy integrated across the board, as you described; I'm just saying as a band-aid it could be halfway done now with less precision.
Ulmo
Active Member
Although not quite the savings of one breaker, this would still be a considerably easier way to install than 400A available to 4 uncoordinated boxes. I forsee that if this is the requirement, the 100A feeder circuit could be brought all the way out into a business parking lot, and right in the middle of the 4 HPWC's, there would be a weather-enclosed load panel as you described, with the 100A feeder in and four 100A breakers, with a conduit out to each HPWC from there. These could double as the within-reach shutoffs? Or would those need to be closer to the HPWC's? It would be nice if Tesla integrated the shutoffs, and perhaps breakers, as ordering options, if the code allowed that.
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Optimizing for one type of EV is a waste of parking space, and parking space is expensive. Really, for this type of public charging setup J1772 connectors should be used to maximize flexibility and minimize cost. It's too bad Tesla doesn't offer a J1772 plug option, I suspect that a good number of people who own Teslas also own other EVs and load-sharing EVSE would be highly valuable.
While this will be useful for charging a network of Tesla's (this must be awesome for service centers, though I suspect the additional cost of installing dedicated 100A circuits is typically peanuts when setting up service centers unless the building does not have enough power), it does not help when trying to charge a mix of EVs.
Also, IMO, adjusting available current level based on SOC seems unnecessary most of the time. It may also be counter-productive to what you want to do - say you plug in two Teslas at the time time, one is at 10% and the other is at 80%. But you have to leave in an hour for a road trip so will be taking the 80% charged vehicle. An hour at 40A will get you fairly close to full, but depending on the power sharing, if the 10% car is getting 68A and the 80% car is getting 12A, you won't pick up much charge.
Another scenario is a public-charging area. If you have 4 HPWCs you don't want all the cars to finish at the same time by prioritizing charging of low SOC cars, you want the cars to finish charging quickly and then be able to move if necessary. In this scenario it's actually better to sequentially charge the vehicles, but IMO simply splitting the charge evenly is probably the more equitable way to do it.
On top of that, if a car plugs in and for some reason is not charging at the maximum rate regardless of SOC, other vehicles should be able to use whatever capacity is left over.
This isn't clear - it appears that one could feed the master HPWC either at the top or bottom and then feed subsequent HPWCs off the other side of the terminal block. All HPWCs are protected by the same breaker so there should be no safety issues here. It will also minimize the length of the service run required to service multiple HPWCs minimizing cost of installation.
Thank you! I'm leaning towards 2 separate breakers as well. I just already had the NEMA plans set up, this would cost a bit more but I think it's better ultimately
tinm
2020 Model S LR+ Owner
I have an S and have a 3 on order. When the 3 arrives, we'll have a garage with one HPWC and two Teslas.
What would be great is if Tesla offered a new solution: a Y adaptor that would connect to the end of the HPWC charger plug, that would in turn then have two 12-ft or so cables each having a charger plug on 'em. So, you could charge both cars with one HPWC. Sure, maybe you get half the power per car, so double the charge... but I'd take that rather than having to install another HPWC or a new NEMA 14-50 or something.
What would be great is if Tesla offered a new solution: a Y adaptor that would connect to the end of the HPWC charger plug, that would in turn then have two 12-ft or so cables each having a charger plug on 'em. So, you could charge both cars with one HPWC. Sure, maybe you get half the power per car, so double the charge... but I'd take that rather than having to install another HPWC or a new NEMA 14-50 or something.
Andyw2100
Well-Known Member
Yes, of course. This is what many of us who live in cold climates do in an attempt to minimize the regenerative braking limit. If the car's battery pack is warm from having just been charged, there is less of a limit. It's just that doing this requires some thought, and constant adjustment to the set charging time. It would be great to see Tesla simplify this process some day, and these new HPWCs could be an indication that as some point they will.
And why would Tesla want to facilitate charging a mix of EVs? The destination charging program is marketing so people see Teslas being charged at the end of a trip, and only Teslas have the range to make trips out of town. Facilitating charging of short range EVs does not help EV adoption, it just demonstrates the limitations of EVs that don't have enough range to make it through the day around town.
Ulmo
Active Member
I'm sure FlasherZ is answering your question right now with more accuracy than I am, but, here's my understanding: if you have more than 100A available from a load perspective on your main panel, then, you have to consider HOW MUCH you have. You can total whatever that is up, and then decide how much you want for each HPWC. Once you figure that out, you can install circuitry, conduit, and breakers, to match that, and set the settings of the HPWC's that way.
For instance, if you have 150A available to use in your main panel, then one HPWC could have a 100A circuit set for 80A draw and another could have a 50A circuit set for 40A draw. They would not communicate with each other, and to charge faster, you'd have to put the car on the 100A circuit (80A draw). You would not need to buy an additional slavable unit.
Or, if you have 200A available, you set up both for 80A draw (100A circuit breakers each). You would not need to buy an additional slavable unit. This is ideal, since you wouldn't have to figure out which car to charge faster, as both would get maximum charge. Typically, affordability of more amps available goes down. I'd be pretty surprised if a high number of people said "oh yeah, 200A, no problem! That's sitting unused in my panel right now!".
Or, if you have (only) 100A (or less) available, you then would WANT to buy an additional slavable unit, take out the old model and put it up for sale once you're done with it, and install the master/slaves both for 80A draw off 100A circuits, each with their own 100A breaker and conduit, installed as per discussed here (or less if less is available).
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Edit: Uhoh. I misread your question. I think those plug in UMC things are dangerous, so I an prejudiced against those, and that guided my misreading. But, here's my newfound interpretation: just get two (of these new slavable) HPWC's, and figure out how to properly install them for your available amps. Most people don't have two hour commutes and only 2 hours of sleep, so in the overnight even with both vehicles plugged in, they should charge up pretty nicely with only a modicum of main panel expense (generally speaking). In your situation, these new HPWC's are fantastic, if you have modest needs and modest main panel availability.
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I really like the future-proofing aspect of these units in a home garage setup: you could set up 3 new HPWC's each with their own 100A wiring, circuitry, etc., back to a dedicated breaker panel capable of handling 400A (for future expansion), with 3 100A breakers to those HPWC's, all on this master-slave bus, set for 100A circuits on all of them (80A draw), and the 400A panel would only be fed with a 100A circuit from the main panel. In the future, if you get a 4th Tesla car and HPWC and want to charge faster, you can upgrade your main panel, output maybe 200A with its own dedicated breaker to the 400A subpanel, and then the only other change you have to make is splitting the master-slave bus in half, with two HPWC's on one half and two HPWC's on the other half, each set drawing up to a maximum of 100A (each set would have one master and one slave), with no additional settings necessary. The physical location of the HPWC's and the 100A circuits to them wouldn't even change. The only thing that would need to change is the communication bus, master/slave settings, the feeder cable to the subpanel, and the feeder breaker, as well as any main panel upgrades to handle this (which of course would be the most expensive part). This makes management of this a lot closer to the actual cost of delivery of the electrical equipment for whatever level of charging someone has.
My "future-proofing" hypothetical house has 4 long-range Teslas that ALL drive 250 miles before coming home AT THE SAME TIME, park, charge up, and then ALL 4 need to leave again AT THE SAME TIME on another 250 mile journey within 4 hours. That might sound crazy to some, and there are "almost no places like that", except for just about every town between Stockton and Ceres including Manteca, Modesto, Tracy, etc., when the Model 3 comes out, and this could become a not unheard of occurrence (people who buy affordable homes who work where the work is around here -- so a LOT of people, that take 580 -- typically not the target market for Tesla, but who knows, some outliars will happen, and they will need more charging than most current Tesla owners would ever imagine needing, just for daily commute needs).
However, the person asking a question made me realize that a household with 150A available for charging would be in a quandry: do they put only 100A on a bus sharing that 100A, or do they set up a few that add up to less than or equal to 150A? Such as wire both for 100A, but set the first one to 64A and the second one to 56A, not bus'd. It would be nice to be able to tell the master "maximum draw from all units is 140A, all on 100A circuit breakers" or some such thing, but no luck here.
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Too much logic and switching required, sadly, it isn't that simple. They need to be able to kill the power to the plug when it is disconnected. By the time they have the parts it in to take care of that, it becomes 2 more HPWC.
It is very clear that you either need a sub-panel with breakers, or a junction box. There is no pass-through terminal block. When using the top feed bracket your power supply connects to the top of the terminal block and the HPWC connects to the bottom of the terminal block. (If you are bottom/back feeding you connect directly to the HPWC and use the low profile bracket.)
Because Tesla has stated multiple times their ultimate goal is to electrify the global fleet. Opening up their patent war chest to the competition was one example of that. As a property owner, I would be very reluctant to install hardware (even if the hardware itself is free) that only services less than half of the plug-in fleet currently on the road when generally the bulk of the cost of installing infrastructure is in the labor to install, not the EVSE.
Thanks for the clarification, I did not notice that. But you may be able to use the top-entry-bracket as your junction box in this scenario to keep the install a bit cleaner and avoid junction boxes at each upstream EVSE.
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Yes, this arrangement primarily will save significant money on the conductors. Only one 100A feeder is required now, instead of independent branch circuits or a 400A feeder. Note that previously some inspectors would allow you to use the 220.62 noncoincident loads provision to attach 2 old-style WC's as long as you messed with setting charge times to make it "unlikely" that they would charge at the same time, but this is much safer and doesn't rely upon your inspector being in a good mood / less of a pedant that day.
The bottom of the terminal block is where you connect the "tethers" from the HPWC unit itself. There is no "magic mating" of the HPWC unit to the terminal block -- you have to connect the HPWC unit (the front part) to the bottom terminals. There's no room for daisy-chaining.
EDIT: The thread is moving so fast I didn't see this answered already - it was answered above. Consider this slapping myself on the hand and I will try to read through everything before responding again.
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