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Range and charge time for full battery

ajdelange

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I did not use NM-B, and probably should have specified. Indeed although NM-B conductors are rated at 90, the cable itself must be sized using the 60 degree rating.
Number 6 is number 6. It has a fixed impedance per unit length and will dissipate the same amount of power per unit length. It's a question of where that power goes or, more particularly, of how much temperature rise that dissipation leads to and what temperatures can be tolerated by insulation, enclosure etc. Thus the current rating of a conductor depends on how many wires are bundled, how many of them are carrying full current, whether they are in a cable or a conduit and the ambient temperature. NN-B is intended to be used enclosed in a wall and does not have particularly temperature resistant insulation. Therefore, it is permitted to carry limited amounts of current and if it is hotter than normal even less.

This unit cannot be plugged in and meet NEC 625.44.
Sure it can if it is provisioned to less than or equal 40A. But I guess the nature of the provisioning is what's in question. What I thought was interesting is that it can only be plugged into a NEMA 14-50 in Canada.


The two areas where it would fail are:
User selectable amperages. In fact, the electrician is instructed to have the homeowner complete the installation using the app to set the amperage.
I thought it might be something like that. But then the user can set the current in a Tesla Gen 2 or Gen 3 HVSE too, in the latter case using the WiFi interface.

I consider the ease in which an owner can set, either accidentally or intentionally, the EVSE to draw over the capacity of the circuit it is installed on to be a fairly major issue.
Umm. The circuit breaker in the panel provides protection (belt). If the driver asks for 48 A on EVSE connected to a 30A circuit the breaker will trip pretty fast. Furthermore, if the car detects high impedance (a smaller circuit will have this because of smaller wire size) it will shut down. But in a proper installation his EVSE would have been provisioned to refuse to charge if he asks for more than 24A. That's the suspenders. If anyone can willy-nilly change the maximum available current we lose belt and suspenders protection. Belt only is doubtless sufficient protection most of the time but the codes wouldn't require the suspenders too if they hadn't saved people from some nasty situations. But what to do? One answer is to allow only the electrician to set the max level. A typical way to do this is to have an "installer's app" and a "users app" with only the first allowing change of the amount of current. Another way would be to restrict current control to the manufacturer. Your electrician would have to call the factory and request that the factory set the device. Another solution would be to only manufacture units of fixed capacity which would really be the variable capacity unit provisioned before delivery by burning fusible links.


Since virtually nothing on the market in recent history uses a J1772 plug and lead acid batteries, the ventilation requirement does not really pose a safety hazard.
Everything coming on the market these days can charge from a J1772. So ???. Clearly though few new vehicles are going to be asserting the "requires ventillation" signal.


This unit cannot be installed using a plug and meet the NEC and therefor most (all?) electrical codes. Hardwired installations are better, but still have issues meeting code.
If the receptacle is no bigger than 50A and the unit is provisioned for no more than 40 A what's the problem? There better not be one as untold numbers of these are sold on Amazon etc. every day.

I do agree that Art. 625 could use some cleaning up.

Anyway, thanks for responding to my question.
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electruck

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@DucRider, to echo AJ, thanks for clarifying your concerns.
 

DucRider

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Just to clarify, code requires that any stationary unit (regardless of amperage, etc) with a plug be mounted in a manner that allows tool free removal. There is no way to do that with the ChargePoint Flex.
 

timesinks

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Since I installed it hardwired, it would not fail for the "fixed in place" (tool free removal) requirement for any stationary equipment using a plug. This unit cannot be plugged in and meet NEC 625.44. It also would not fail for the GFCI outlet required in 625.54 since ChargePoint states that if a GFCI outlet is required by code, the EVSE must be hardwired. The GFCI requirement is somewhat contradicted in 625.22 where it specifies that the required personnel protection system can be located in the EVSE itself.
I don't see a "tool-free" removal requirement...

"(B) Stationary Equipment. Stationary equipment intended to
be fastened in place in such a way as to permit ready removal
for interchange, facilitation of maintenance or repair, or repo¬
sitioning shall be connected to the premises wiring system by
one of the following methods:"

Maybe it's up to your local department's interpretation, but in my jurisdiction, our Chargepoint Home is screwed to the wall and uses plug-and-cord (Allowable under B for "stationary equipment"). The code says stationary just means it's installed in such a way to permit ready removal -- it doesn't say you can't use simple tools to effect such removal.
 

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DucRider

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I don't see a "tool-free" removal requirement...

"(B) Stationary Equipment. Stationary equipment intended to
be fastened in place in such a way as to permit ready removal
for interchange, facilitation of maintenance or repair, or repo¬
sitioning shall be connected to the premises wiring system by
one of the following methods:"

Maybe it's up to your local department's interpretation, but in my jurisdiction, our Chargepoint Home is screwed to the wall and uses plug-and-cord (Allowable under B for "stationary equipment"). The code says stationary just means it's installed in such a way to permit ready removal -- it doesn't say you can't use simple tools to effect such removal.
2017 & 2020 NEC 625.2
Rivian R1T R1S Range and charge time for full battery 1604260098882

2020 NEC 625.44
Rivian R1T R1S Range and charge time for full battery 1604260234127

2017 NEC 625.44
Rivian R1T R1S Range and charge time for full battery 1604260564393


The 2020 NEC further clarifies that plug in equipment be removable without tools, but the 2017 version does have that requirement as well.
 

timesinks

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2017 & 2020 NEC 625.2
1604260098882.png

2020 NEC 625.44
1604260234127.png

2017 NEC 625.44
1604260564393.png


The 2020 NEC further clarifies that plug in equipment be removable without tools, but the 2017 version does have that requirement as well.
Thanks for the full citations... that seems silly, but it is pretty clear.
 

ajdelange

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Fastened in place and portable (distinction - intended to be carried with the vehicle e.g. Black Mamba, Tesla UMC) equipment must be connected by one of the 4 plugs. All other must be hard wired. Thus your decision as to how you hang it determines how you must feed it in order to be compliant with NEC. There is, of course the further restriction that your circuit must be 60A or less with a plug installation limiting you to 48A or less which, as it is the most a Rivian will take is sufficient is hardly a burden. The obvious advantage of the plug based Fastened-in-place choice is that you can move the EVSE to another location such as a summer home. But there is a catch. No portable or fastened-in-place may have adjustable settings per Art. 625.42 the pertinent sentence of which reads "Adjustable settings shall be permitted on fixed-in-place equipment only." Thus, as the ClipperCreek box in question has adjustable settings it may not be installed fastened-in-place. It must be fixed-in-place. Obviously it doesn't make sense to do this in such a way that it can be commissioned at 50A output as that would require the use of a separate lockable disconnect, the high temperature wire and splices I described in an earlier post which is hardly necessary for the extra 2 amps which your truck won't be able to take anyway.

Mount it fixed and wire it with No. 6 75° wire to a 60A breaker and you are compliant with the 2020 NEC except perhaps for one additional requirement again imposed by 625.42 and that is that "Restricted access shall prevent the user from gaining access to the adjusting means".

Three acceptable means are given:

(1)A cover or door that requires the use of a tool to open
(2)Locked doors accessible only to qualified personnel
(3)Password protected commissioning software accessible only to qualified personnel

Note that Tesla implemented (1) in their Gen 2 HPWC by placing the programming switch behind a cover secured with security Torx screws. Their Gen 3 uses ordinary Torx20. Thus Tesla meets the requirements of 625.42 via (1) but clearly their method does not supply much "protection" against a determined user.

ClipperCreek is commissioned via software and I don't know whether it is set up in such a way to restrict access to "qualified" personnel. Then we have to ask ourselves "Who are the qualified personnel?"

Article 100 defines a qualified person as "One who has the skills and knowledge related to the construction and operation of the electrical equipment and installations and who has received safety training to avoid the hazards involved." Of course the question I ask myself is as to whether I would be considered qualified.



Sometimes it is a good idea to step back and look at the forest rather than focusing too much on a particular tree. ClipperCreek and Tesla (and others) sell a lot of EVSE. Were the majority of the ones they sold returned because they couldn't get past inspections then the companies would change the designs to make them comply. Let's face it. Tesla's way of satisfying 625.42 is a joke. Yes, it meets the requirement because it requires a tool but lest you don't have a Torx set handy they provide you with the T20 bit in the package. In any event it is clear that Tesla and ClipperCreek installations are being accepted by inspectors all across the country every day and that, therefore, this isn't something readers need to worry about.

Clearly Article 625 needs work.
 
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DucRider

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I agree with AJ with most of the above, and 625 definitely needs work.

A couple of the things I noticed in AJ's post:
Plug in units (both fastened in place and portable) are limited to 50A outlets or less resulting in 40A (9.6 kW @ 240V) available for charging.

The unit under discussion is the ChargePoint Flex, and not manufactured by Clipper Creek.

I believe the restriction on adjustable charging rates for equipment that is not "fixed in place" is to prevent it being moved to a different location with a lower capacity circuit than it is set for and therefore drawing more than the allowed amount. There are "shake to adjust" portable units sold with a variety of adapters to plug into almost any circuit. Many people would simply find the adapter that fit, plug it in and start charging. They would not pay attention to (or possibly even be able to identify) the allowed amperage for a given adapter. I have zero experience with how hard you have to shake these to get the charging amperage to change, but it is also possible they could be jarred inadvertently and have the setting change with the user knowing. This is the type of unit and usage case this section is designed to protect well meaning, but somewhat oblivious, consumers from. I could identify the amperages allowed for at least most plugs, but my wife wouldn't even understand the concept (not a criticism of her intelligence, she just isn't interested and doesn't care to learn). The code has taken a stab at allowing adjustability with provisions to make it safe to do so. To be honest, the adjustment thru the app by the user bothers me and creates a definite safety issue. In the vast majority of cases, setting too high of a draw will simply result in a breaker tripping. It's the minority of outcomes that are troublesome.

I am in know way arguing that the units sold that cannot be installed to meet the NEC are inherently unsafe. I installed mine in a manner that I consider safe and have no worries. But, the fact that they cannot meet code should be addressed by the manufacturer - either by complying with the code or working to get the code changed.
 

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It is quite simple to determine your daily energy and charging time requirements. If you drive 80 miles per day you will, in each day, deplete 80/400 or 20% of the battery. Range of 400 mi implies you have the 180 kWh pack and so to replenish the power you use on an 80 mile day you will need 0.2*180 = 36 kWh. The time required to take on that charge is 36/P where P is the power the charger can deliver in kW. For example, if you install Rivian's home charging termnal on a 60 A 240V circuit you will realize the maximum potential of the truck's on board charger which is 11.52 kW. You will replace the 36 kWh in 36/11.52 = 3.125 hr - actually a wee bit longer than that as the charger is not 100% efficient.

If you were using an old EVSE capable of handling only 3 kW then you would need 36/3 = 12 hrs +.
Question #1:
This is very helpful. This will be my first EV, and I'm not an EE, so just to confirm my understanding:
If you have a 135 kwh battery, drive it roughly 75% of the way to empty (~35 kwh remaining) on a road trip and pull up to a 300 kw charger. You should be able to charge to full in roughly 20-30 minutes (understanding this is just an indicative time)? If it is a 50 kw charger, you are looking at 2 hrs?

Question #2:
While I plan to have a home charging terminal. If I am on the road, and stay at a friend's place overnight where there is not charger - What can I expect in terms of charging rate if I were just to plug into a traditional outlet? I assume this does not utilize the full potential of the 11.52kw onboard charger?

Thank you in advance!
 

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DucRider

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Question #1:
This is very helpful. This will be my first EV, and I'm not an EE, so just to confirm my understanding:
If you have a 135 kwh battery, drive it roughly 75% of the way to empty (~35 kwh remaining) on a road trip and pull up to a 300 kw charger. You should be able to charge to full in roughly 20-30 minutes (understanding this is just an indicative time)? If it is a 50 kw charger, you are looking at 2 hrs?

Question #2:
While I plan to have a home charging terminal. If I am on the road, and stay at a friend's place overnight where there is not charger - What can I expect in terms of charging rate if I were just to plug into a traditional outlet? I assume this does not utilize the full potential of the 11.52kw onboard charger?

Thank you in advance!
#1. Charging slows considerably as the battery fills. When DCFC on a road trip, it is very likely to be better to charge to only ~80%, and start the charging session with as low a battery % as you are comfortable with (and circumstances dictate).
An example from a Model 3
Rivian R1T R1S Range and charge time for full battery 1605833520872


Rivian is promising sustained charging at over 200 kW. We'll see what that actually means when people get production spec vehicles to test.

#2
The Rivian will come with a portable EVSE that can plug into a 120V outlet. It will supply 1.4 kW when used in that manner (if they have a 240V outlet available, the portable unit can also use that and charge much faster, but what plug style it uses and what - if any - adapters are included/available has not yet been announced)
 

ajdelange

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Question #1:
This is very helpful. This will be my first EV, and I'm not an EE, so just to confirm my understanding:
If you have a 135 kwh battery, drive it roughly 75% of the way to empty (~35 kwh remaining) on a road trip and pull up to a 300 kw charger. You should be able to charge to full in roughly 20-30 minutes (understanding this is just an indicative time)? If it is a 50 kw charger, you are looking at 2 hrs?
0.75*135/300 = 0.3375 so yes, it will take approximately 20 minutes but note that 300/135 = 2.222. That indicates rather rough charging so the car may limit itself to less than 300 kW. If you pull up to a charger with a cold battery the car will ask for less or if it is a particularly hot day the car will ask for less. Also, dependent on battery chemistry, the charge will be tapered as the battery approaches fullness so you are probably wise in expecting up to 30 minutes.

0.75*135/50 = 2.025 so about 2 hrs from a 50 kW charger. Again, yoy may run into some taper if you get into the higher SoC regions but 50/135 = 0.37037 which is a much gentler charge and you won't experience as much.




Question #2:
While I plan to have a home charging terminal. If I am on the road, and stay at a friend's place overnight where there is not charger - What can I expect in terms of charging rate if I were just to plug into a traditional outlet? I assume this does not utilize the full potential of the 11.52kw onboard charger?
That's correct. The typical 120V outlet is on a 15 A circuit. Many are on 20 A circuits but to be on the safe side the charging adapter that comes with the car will assume it is a 15 A circuit and allow 80% of that i.e. 12 A. That's 1440 W at 240 V. The R1's are going to use about 420 Wh/mi and so each hour of charging will replenish approximately 1440/420 = 3.4 miles. A 10 hour session will thus only restore about 34 miles which isn't that much for sure but may be enough to add some comfort to your drive of the next day.
 

MReda

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They also said 140 miles in 20 minutes. My guess is they selected those exact specs because there is a peak in the curve rate that roughly aligns with that.
 

azbill

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They also said 140 miles in 20 minutes. My guess is they selected those exact specs because there is a peak in the curve rate that roughly aligns with that.
That number matches up with charging at approximately 190Kw for 20minutes. That also represents 45% of the battery. Almost all vehicles today, except Tesla, do not have significant taper until reaching between 50% and 70% SOC. so ,if you assume a starting SoC of 10-20% and ending at 55-65%, then the 140miles in 20 minutes makes perfect sense for 200KW charging rate.
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