Colorado Checking In

[DucRider]

Interesting about the 220 vs. 240. The rest of your post might as well have been written in Sanskrit. You electrical engineers always know how to crack me up!

Basically there is a pilot signal on a single wire/pin in the between the car and the EVSE.
Changing the voltage sends one type of signal (ready, charging, etc)
They use PWM (Pulse Width Modulation) to signal how much current is available. It is essentially a "dimmer" that keeps the voltage the same. Many Daytime Running Lights that use the normal high beam bulbs do this. The lights are dimmer at the normal 12-14V because the power is cycled on and off very rapidly.
In the above table, if the power was on 50% of the time, it would indicate the EVSE could provide 30A.

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[photontorque]

@Gshenderson and @manitou202 -- spectacular feedback, thank you!

Looking forward to comparing notes on actual vehicle performance!

 

[ajdelange]

What happens when you're stuck for an extra hour in I-70 ski traffic with cold weather?

You get frustrated, angry and bored - same as in an ICE vehicle! OK, wiseguy crack aside I know you are concerned about energy use. Well you aren't wasting any fuel on idling the engine or creeping along in parts of the engine envelope where efficiency is low. You will use about 450 Wh of battery for each mile you drive if the road is clear of snow and dry. If it is snow covered or wet that will increase by as much as 30% or even more. This is, IMO, the biggest factor in range loss in winter based on my experience but I have not driven in a Colorado blizzard.

Many worry about heat and yes, of course that must come from the battery too and if you are not moving then it must be deducted from the energy available from traction or it must come from the outside air as there isn't any motor or inverter waste heat available. We (or I, at any rate) don't know anything about the details of the Rivian HVAC system but we can still make a couple of remarks. One kW is equivalent to 3412 BTU/hr which is equivalent to about 1/4 ton of heating. Thus, if you can keep the cabin warm with a quarter ton of heating you would use 1 kWh to keep it comfortable for an hour. I keep a pretty big house warm with an 8 ton heat pump running at 25% duty cycle so that's equivalent to 2 tons and so if my car's cabin is less than 8 times that of the house, and I am absolutely sure it is, then I ought very well to be able to keep it warm on 1 kW of electric heat. Note also that when driving at 60 mph 1 kW heating adds 1000/60 = 17 Wh/mi to the consumption. This is why I think road conditions are the major contributor to lost range in winter.

The OEMs and BEV drivers have learned that driver and passengers can be quite comfortable at low cabin temperature if their backs and backsides are warmed by heaters in the seats. The Rivians have this.


Now the cabin isn't the only thing that needs to be kept warm. The battery needs to be kept warm too because if it isn't there are limits on how fast you can charge and discharge it. Once you get going the battery warms itself to some extent and there is, in cruise at speed, also waste energy from the inverters and motors to keep it warm but it might, sitting in traffic in cold weather, need some auxiliary heat and that would have to come from the battery itself or from outside air. How this works will depend on the details of the Rivian design. Can it's heat pump, which pumps excess heat overboard in the summer run in reverse in the winter (a couple of BEVs have this)? Is the battery pack well insulated? I don't know the answer to those questions.

... I also wonder what happens to the battery charge if you leave a Rivian parked in the cold weather at the ski resort all day.

Actually, nothing. But there are some implications with regard to performance until the battery gets warmed up as mentioned above. As an example of this, regen may be restricted or unavailable and in the scenario which involves driving up hill to a ski resort, cold soaking the battery all day and then driving down hill to return home you could lose your uphill "investment" in potential energy. This could represent a range problem going home. The fix to this is to drive home in such a way that you never need regen or the friction brakes. These comments need to be modulated by the fact that we don't know how Rivian will handle regen. Perhaps they will be less conservative with it than Tesla is.

Our E-tron and Model X only lose about 1-3% on a cold day parked outside at the ski resorts.

My MX loses 1 - 3% sitting in my garage or outside on a warm spring day. IOW it's not weather related but rather related to the phantom drain imposed by reporting to TeslaFi and Stats plus what ever else the car needs to keep itself aware.

Also sitting in traffic blasting the heat uses about 2000-3000 watts continuously which equals about 2-3 kWh/hr. So for a 135 kWh battery that's about 2%/hr sitting in traffic.

I'm really skeptical about that for the reasons mentioned above. Three kW is almost a ton of heat. Are you growing orchids in the car? I have measured the energy consumption of my X heater and while it may peak at over 2 kW it only does so for a few minutes at most before cycling on and off at a low duty cycle just as one would expect it to.

 

[ajdelange]

I can't speak to your situation, but what kWs are those J1772s that you are referring to pushing and what is the Tesla's acceptance rate when utilizing your Tesla EVSE?

Interesting about the 220 vs. 240. The rest of your post might as well have been written in Sanskrit. You electrical engineers always know how to crack me up!

You lay people really crack me up too but the story on EVSE is really quite simple at the top level. Current flowing through a wire (or anything else except a super conductor) heats it by an amount that depends only on the square of the current irrespective of the voltage pushing that current (many like to think if voltage in the the same way as pounds per square inch water pressure and current in the same way as gallons per minute flow rate). Thus safety procedures limit current. The EVSE is rated for a certain current and thus must be protected by a circuit breaker rated relative to that current and connected by wiring that can safely carry that current. The EVSE must tell the car how much current can be taken from it and it is the job of the car to insure that it does not take more than that.

Now what you pay the utility for and what moves your car is energy. This is calculated by multiplying current by voltage and then by time. Your power company meter does this. Your utility supplies a voltage that varies about some average. That is usually 240 V. Note that as I am writing this my utility is actually delivering 245 V. In some places the average voltage is 220 V and in some 208. Your car controls the current it draws. It will draw whatever you tell it to up to the limit that the EVSE tells the car it can safely supply and it does this by signalling that current limit over one of the two skinny pins in the J1772 plug. That limit is programmed into the EVSE when it is manufactured or at installation by, for example, setting switches in the equipment or over WIFI at commissioning.

The charger in the Rivian will never ask for more than 48A and it will only ask for that much if'
1)You tell it to
2)The EVSE tells it it can have that much.

Given this the amount of energy taken from the utility depends on the voltage and the length of time you draw at the 48A rate. For 208 V it is 208*48 = 9984 W which is 9.984 kW and you will be billed for 9.984 kWh for each hour you charge at 48A. For 220 the rate is 10.560 kW and for 240 it is 11.520 kW. As most service in North America seems to currently be 240 V the charger in the Rivian (and Tesla and...) is generally spoken of as being capable of 11.52 kW even though, were I to start charging my X at the maximum rate right now I would be taking 11.760 kW.

The conclusion is that you might get as little as 9.984 kW and as much as 11.760 kW from these chargers. That's an 18% spread which translates to an 18% difference in the amount of time it takes to take on a gven number of miles or an 18% spread in the number of miles that can be taken on in a given time. Does anyone care about this?

 

[Fenwayfan77]

You lay people really crack me up too

 

[MReda]

https://www.cpr.org/2020/12/25/reba...million-plan-approved-by-colorado-regulators/

 

[ajdelange]

J1772 standard:

The J1772 Pilot is a 1khz +12V to -12V square wave, the voltage defines the state and the duty cycle defines the current available to the EV. The EVSE sets the duty cycle and the EV adds resistance from the pilot the Ground to vary the voltage. The EVSE reads the voltage and changes state accordingly.​

​

State Pilot Voltage EV Resistance Description ​

State A 12 N/A Not Connected ​

State B 9 2.74k Connected ​

State C 6 882 Charging ​

State D 3 246 Ventilation Required ​

State E 0 N/A No power ​

State F -12 N/A EVSE Error ​

​

Pilot Duty Cycle - The Pilot Duty Cycle is dependent on the Max current setting of the EVSE. ​

Up to 51A Amps = Duty cycle x 0.6 Duty cycle = Amps / 0.6​

51 - 80A Amps = (Duty Cycle - 64) 2.5​

​

Duty Cycle Max Current ​

10% 6A ​

...​

​

50% 30 A​

...​

96% 80A ​

​

Basically there is a pilot signal on a single wire/pin in the between the car and the EVSE.
Changing the voltage sends one type of signal (ready, charging, etc)
They use PWM (Pulse Width Modulation) to signal how much current is available.

So far, so good.

It is essentially a "dimmer" that keeps the voltage the same. Many Daytime Running Lights that use the normal high beam bulbs do this. The lights are dimmer at the normal 12-14V because the power is cycled on and off very rapidly.
In the above table, if the power was on 50% of the time, it would indicate the EVSE could provide 30A.

But this part - not so good.

The vehicle connects a resistor to the control line to tell the EVSE when it should connect the vehicle to the mains. The EVSE senses the voltage on the control pin (controlled by that resistor)to determine when it is safe to turn on or must turn off. The EVSE modulates the voltage with a square wave whose duty cycle determines how much current the vehicle is allowed to take from the EVSE.

But the EVSE does not do any regulation. All it does is connect the car to the 110, 120, 220, 240. 250 ... V (whatever the mains voltage happens to be) and the car converts that relatively low AC voltage to a DC voltage high enough to charge the battery. The incoming full mains voltage, whatever it may be, is rectified (converted to DC) and that DC is then upconverted to a DC level higher than that of the battery so that current will flow into the battery, When controller increases the DC/DC converter's output voltage more current flows to the battery and this also causes more current to be taken from the mains (at whatever voltage). The charger uses the "control the voltage to regulate the current" scheme which means simply that it will increase its output voltage until the mains (input) current is less than or equal to the current limitation communicated to it by the EVSE's square wave signal. Thus the charging status display in a Tesla might indicate 25/40A 243V indicating that the charger is drawing 25A from 243 V mains even though the EVSE is signaling that up to 40A available (as it would if properly provisioned on a 50A circuit). The most it will ever indicate is 40/40A vvv which it will do if the driver selects the maximum available current (he cannot select a level higher than that signaled by the EVSE).

Compare this to Level 3 charging which is, conceptually, exactly the same except that the voltage regulated upconverter is in a cabinet behind a fence at the charging station rather than in a wheel well in the vehicle. This means that the voltage feedback signal to the upconverter must be communicated externally. This also is done via the CP (Control/Pilot) pin in accordance with pertinent DIN and ISO/IEC standards).

So the glaring error in the quoted post is

It is essentially a "dimmer" that keeps the voltage the same.

It's nothing like that at all. It is a voltage regulated DC/DC upconverter whose voltage set point is varied to keep mains and battery currents within desired limits.

I think the misunderstanding stems from the bandying about of "PWM". It's a good tecchy sounding "buzz word" that has recently found its way into common use as PWM related techniques have become more and more common in consumer electronics. A modern hifi may well use a "Class D" amplifier which is sort of bi polar PWM. The inverters in our BEVs use vector space control which is a sort of 2 dimensional PWM. And in the current case signalling the capacity of EVSE via the duty cycle of a square wave is referred to as PWM even though nothing is modulated at all!

 

[cohall]

https://www.cpr.org/2020/12/25/reba...million-plan-approved-by-colorado-regulators/

Excellent news. Thanks for sharing.

I had a 14-50 outlet installed in my garage last week, but will hold off on buying any charger until this takes effect, in order to claim the $500 rebate.

 

[lg3103]

Can't imagine a place better than Colorado for a Rivian. No power loss from altitude? 4 wheel power for the various conditions? Ground clearance for all the trails? Seating for 7, gear in front, gear in back, skis on top? CHECK, CHECK, CHECK, CHECK. Any other Colorado (Denver) pre-orders here?

Newbie here in Denver (reserved on 10/8), but already can't wait!

Welcome to the Forum. Preordered early 2019 and reserved R1S LE on first day. Hope I can get mine as an early Christmas gift for myself next year. Tesla’s are fun on the road. Looking forward to an actual off-road vehicle.

 

[MReda]

This might be interesting to some of you, since he stops at some of the CCS chargers, and discusses them a bit:

 

[Rhidan]

This might be interesting to some of you, since he stops at some of the CCS chargers, and discusses them a bit:

Thanks! A little disappointing that those CCS stations the State has put in appear to be limited to ~60 kWh. The pricing structure ($.20 kW +$.25/min) is also disappointing. But between EA on the interstates and these new stations, there’s not much else I guess. There’s still a long way to go before the whole of the state is available from DCFC.

 

[cohall]

Someone on Facebook has stated today that they were informed over the weekend that Rivian is currently building "Their first store" in RiNo, and that it will be opening soon.

I've asked for clarification on the reliability of the source. But that would be great news if it ends up being true.

Just thought I'd share.

 

[MReda]

Someone on Facebook has stated today that they were informed over the weekend that Rivian is currently building "Their first store" in RiNo, and that it will be opening soon.

I've asked for clarification on the reliability of the source. But that would be great news if it ends up being true.

Just thought I'd share.

Interesting, keep us updated. Presumably, that means there must be a permit on file somewhere... If I get a chance later, I'll do some searching.

 

[timesinks]

I went searching through Denver records but couldn't find Rivian as a party to any transactions. So I asked whether they had registered as an entity yet...

https://www.sos.state.co.us/biz/ViewImage.do?masterFileId=20211110592&fileId=20211110592

Coincidentally, they registered in CO as a foreign LLC just this morning. That's generally a prerequisite to being able to enter into contracts / own property within a state.

 

[Rhidan]

Someone on Facebook has stated today that they were informed over the weekend that Rivian is currently building "Their first store" in RiNo, and that it will be opening soon.

I've asked for clarification on the reliability of the source. But that would be great news if it ends up being true.

Just thought I'd share.

That’s where I live. ? I will do a ton of investigating here. In the past year they have opened a Patagonia and Burton a block away from me. Might make sense to co-locate here. A commercial real estate company also just bought another large block in RiNo, but there are plenty of pre-built spots if they are looking to open something this year.

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