Rivian Battery Poll - VOTE HERE

[ja_kub_sz]

Again the 180kwh is a must for me.

I found with my previous EV and my driving habits that range is basically at 75% the listed capacity. One of my typical commutes for work is 125 miles one way, which will probably drop my range down 160 miles, so just that drove alone to and from work with no charging would put me at 60-80 miles of remaining range. And that's barring a polar vortex which could put me in an even worse spot.

I told RJ at event "sometimes just making it to work is part of the adventure".

My long distance driving and frequent inclement weather basically drove me away from EV's after my Tesla. After a few times of having to reduce my speed and turn off the heat in my Model S just to make it home during the winter I told myself NEVER AGAIN!

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[jarross]

I feel that I have no other choice than to go with the 180 kWh battery. I live in Wyoming and there are currently ZERO CCS chargers here. There are a couple of level two's for emergencies, but my reality is that my battery will have to be enough for most of my excursions round-trip. I've talked to Electrify America and they submitted a proposal for the three places I believe most strategically meet my charging needs to not worry at all. My most common adventure is 330 miles round trip and 100 of it being 70 mph speed limit. It's gonna be close without a CCS charger in Shoshoni...

 

[Babbuino]

I feel that I have no other choice than to go with the 180 kWh battery. I live in Wyoming and there are currently ZERO CCS chargers here. There are a couple of level two's for emergencies, but my reality is that my battery will have to be enough for most of my excursions round-trip. I've talked to Electrify America and they submitted a proposal for the three places I believe most strategically meet my charging needs to not worry at all. My most common adventure is 330 miles round trip and 100 of it being 70 mph speed limit. It's gonna be close without a CCS charger in Shoshoni...

I wonder if they'll have a battery range extender for the R1T... i remember hearing about it in the past

 

[ajdelange]

Don't forget that you are not limited to CCS chargers. You can also charge at Tesla Destination chargers and at camp grounds that have hookups for trailers. These will only get you perhaps 20 miles of range per hour charging but that's better than no charging at all. A 400 EPA mile rated vehicle has a "working range" of around 320 miles. Given that your adventure involves a 330 mile round trip you wouldn't have to add that many miles - perhaps only 2 or 3 hours worth. That will depend on conditions. Taking the 70 mph leg at 60 could save you quite a bit. That's your battery range extender right there.

 

[ohmman]

Since I'll be towing, 180kWh for sure.

Regarding the real world vs. EPA range question, everyone's experience differs, but my experience and driving style has meant that in both my Model S and Model X, I exceeded the EPA range over the lifetime of those cars. That doesn't include when towing with the X, of course. We live in a temperate climate, though, and in our small town highways aren't a consistent part of our life.

I feel like for daily driving, I'll exceed the EPA range on the Rivian as well, but do expect it to be cut approximately in half when towing our camper. And potentially even less if the acquisition of the Rivian encourages me to get a slightly larger camper..

You can also charge at Tesla Destination chargers

Is there an adapter for this? Because the destination chargers that use HPWCs have Tesla's proprietary connector on them.

 

[ajdelange]

Since I'll be towing, 180kWh for sure.

Always better to have them and not need them than to need them and not have them.

Regarding the real world vs. EPA range question, everyone's experience differs, but my experience and driving style has meant that in both my Model S and Model X, I exceeded the EPA range over the lifetime of those cars.

I have had a X100D and a Raven X. In the former my consumption was, on average, better than rated. In the latter worse. I have not changed my driving style nor where I drive. Yes, YMMV.

I feel like for daily driving, I'll exceed the EPA range on the Rivian as well,

Don't count on it until you have demonstrated to yourself that this is indeed the case. Even so, don't count on it as even with the X100D there were drives (e.g. with a headwind or wet road) where consumption was higher than rated.

Is there an adapter for this? Because the destination chargers that use HPWCs have Tesla's proprietary connector on them.

www.amazon.com/TeslaTap-AMP-Tesla-J-1772-Adapter/dp/B07TQDKZQC

 

[DucRider]

Most people will easily exceed the EPA rated range with a mix of 30% freeway/70% secondary road driving and moderate temperatures. In hot weather, the EPA range is probably going to be fairly accurate. In cold weather, you will see a lot less range.
That 330 miles in Wyoming winter is potentially going to be an issue and some charging will likely be needed. In spring/fall (and likely summer), I can see it as possible, but much depends on factors we don't yet know (actual EPA ratings, etc)

 

[ajdelange]

Also keep in mind that there will be tools in the car that will help you to understand your battery status as you go. After you load a route the car will estimate the amount of charge remaining at your destination. As you progress along your journey that estimate will be continuously updated. If you experience a head wind the estimate will fall. If you have a tail wind it will increase. If you slow down it will increase etc. It will take you a while to learn to interpret the various displays and to get comfortable with the concept of Wh/mi (and it never comes to some) but it isn't rocket science.

 

[DucRider]

the concept of Wh/mi

That metric is unique to Tesla. All other manufacturers (AFAIK) use mi/kwh. Fits more with what people are used to - if you have a 15 gallon gas tank and get 30 mpg, your range is 450 miles,. With a 100 kWh battery and 4 mi/kWh your range is 400 miles. Gas is sold by the gallon and you get x miles from that gallon. Electricity is sold by the kWh and you get y miles from that kWh. Wh/mi is a better metric for some calculations, but a bit harder for many to grasp.
Tesla is also unique in that its range estimate is based on SOC% times rated range (or possibly rated Wh/m * battery energy remaining). All other manufacturers have the "guess-o-meter" factor in recent driving and adjust the estimate accordingly. If you have been traveling at high speed or in cold weather, a full charge will show a lower number. This has been known to cause a degree of consternation from new owners with concerns that their battery has an issue. Conversely, if you have been driving efficiently, your range display with a full charge will exceed the EPA rating.
Both "guess-o-meter" methods have pluses and minuses. If you are on a long trip with sustained 80 mph speeds, the Tesla will reset to its full range rating after charging and be optimistic until SOC drops significantly. A Chevy Bolt would show a more accurate range estimate after a full charge in that circumstance, but if your upcoming trip is different than your recent driving pattern, the number could be wildly inaccurate. People adapt to their particular vehicles as they gain experience - as an example it is not unusal for a gas car to have the fuel gauge level drop faster as the level drops and people learn to account for that.

 

[electruck]

@DucRider In the US we're more accustomed to mpg but a good portion of the rest of the world denotes ICE fuel economy as L/100 km.

 

[ajdelange]

That metric is unique to Tesla. All other manufacturers (AFAIK) use mi/kwh.

I'll have to take your word for that as I only know Tesla. But we are talking Rivian here. They will probably do something like what Tesls does as it makes it much easier to understand.

Fits more with what people are used to -

Even EPA understands that MPG confuses people - the "MPG Illusion" - and so, while the Monroney sticker is still required to exhibit it, it is also now required to show gallons/mile.

if you have a 15 gallon gas tank and get 30 mpg, your range is 450 miles,. With a 100 kWh battery and 4 mi/kWh your range is 400 miles. Gas is sold by the gallon and you get x miles from that gallon. Electricity is sold by the kWh and you get y miles from that kWh. Wh/mi is a better metric for some calculations, but a bit harder for many to grasp.

The situation I was discussing is the one in which a driver is trying to decide whether he will make it to his destination. He looks at his gas gauge. It is 40% full. He's got a 15 gallon tank so he knows that he's got .4*15 = 6 gallons. He has 90 miles to go and he is using not 0.033 gpm but rather 0.05. Ninety times 0.05 = 4.5 gallons. He'll make it.

Now look at the BEV. He's got a 100 kWh battery and uses and has a rated rate of 250 Wh/mi. But his gauges show that over the last 30 miles he has been using 300. He's got 90 miles to go so he'll need .3*90 = 27 kWh. His battery gauge shows 47% SoC which is 47KWh. He'll make it with 20 kWh margin.

The difference between the petrol and electric situations is that the BEV gives lots more information and the numbers somehow seem easier to work with. The BEV will tell you your percentage remaining charge in percent (as opposed to E, 1/4, 1/2 and F). It is possible from the % reading to come up with a crude estimate of your fuel condition just by multiplying the gauge percent by the EPA range e.g. 47% battery is a Raven X (EPA 351) is about 160 miles. If you know that your actual consumption has been closer to 300 wh/mi than 250 Wh/mi you can get a more refined guess at 47/.3 = 156.

Tesla is also unique in that its range estimate is based on SOC% times rated range (or possibly rated Wh/m * battery energy remaining).

Some people get really angry when I explain this and yell that they aren't mathemeticians and that they don't want to be doing all these calculations when they are driving. Well this ain't Fields Medal stuff. You don't do the detailed calculations. You do approximate ones. To say I've got about half the battery and can go about half of 351 i.e. 175 miles when all I have to do is 90 is adequate. These people never see the advantage of thinking in Wh/mi and for them Tesla allows setting the battery gauge to read in remaining miles (range) calculated by multiplying rated consumption by the estimated charge left in the battery. When driving the car is calculating the energy you used over the last 0.1, 5, 15 or 30 miles and divides by 0.1, 5, 15 or 30. IOW it calculates Wh/mi averaged over that distance. It divides its estimate of the battery's remaining charge by that number to calculate an estimate remaining range based on the previously encountered actual driving conditions.

If you use the navigation system (lay in a route) the car will estimate the SoC at every point along the route using the rate Wh/mi and knowledge of the terrain along the route. This is presented as a graph of SoC vs distance. As the drive progresses a second trace is overlain on the graph showing actual SoC at every point prior to the current position and a new projected SoC vs remaining distance based on the current SoC, the rated Wh/mi and the coming terrain.

If you are on a long trip with sustained 80 mph speeds, the Tesla will reset to its full range rating after charging and be optimistic until SOC drops significantly.

If you are on a long trip with sustained high speed driving and stop for a charge upon resumption the navigation system will do just what it did before the stop i.e. rely on the historical consumption over the last however many miles you have chosen as your averaging window if in the simple energy monitoring mode. In the trip energy monitoring mode it will also do what it did before: project the future part of the trip based on rated consumption and terrain ahead.

All other manufacturers have the "guess-o-meter" factor in recent driving and adjust the estimate accordingly.

Can't speak to the other manufacturers as I have no experience with them but I expect that Rivian will do something close to what Tesla does. They are smart enough to recognize the excellence of the Tesla system. Unless, of course, patent infringement is involved.


I guess that as a matter of full disclosure I should point out that the Wh/mi system seemed common sense to me as I have had some experience with airplanes. In an airplane fuel management is handled by looking at gph fuel flow and updated estimates of the hours to destination. I have seen evidence from other forums that it makes no sense whatsoever to some.

A Chevy Bolt would show a more accurate range estimate after a full charge in that circumstance, but if your upcoming trip is different than your recent driving pattern, the number could be wildly inaccurate.

Which is doubtless while Tesla did not decide to base the future on information it does not have. The past is a terrible predictor of the future unless you have a model. Tesla does. The terrain. Oh, and I almost forgot, speed limit data.


The question here is "What will Rivian do?" The advantages of Tesla's approach are clear but there is one other source of information available and that is weather data. I is available and could be inserted into the predicor algorithm. The catch is, of course, that if you buy it in the quantities that Tesla would need to, it gets expensive. And it is, of course, ephemeral. But Rivian could add this and top Tesla.

People adapt to their particular vehicles as they gain experience

That's a very important point. The first thing to do with a new car is set the trip odometers up in such a way that they are giving you wh/mi information you can use. What you want to know is how many Wh/mi you use driving about town as opposed to what that number is on the freeway. You need to learn how many Wh/mi an extra 20 mph in airspeed costs (this can come from speeding up 20 mph in calm or encountering a 20 mph headwind) and what rain adds. Subscribing to something like TeslaFi records information on every drive and every charge and helps in this learning.


It is necessary to warn that there is some art involved in managing a BEV. Some people will not be able to acquire it. They are the ones that wind up running out of battery 10 miles from the charger.

 

[DucRider]

Now look at the BEV. He's got a 100 kWh battery and uses and has a rated rate of 250 Wh/mi. But his gauges show that over the last 30 miles he has been using 300. He's got 90 miles to go so he'll need .3*90 = 27 kWh. His battery gauge shows 47% SoC which is 47KWh. He'll make it with 20 kWh margin.

Math is just as easy for others.
Say you have been averaging 3 mi/kWh. Gauge shows 50% charge which is 50 kWh, so 150 miles of range left.

It is important to note that many EVs have a fuel gauge similar to ICE vehicle with about the same resolution. Sometimes you can access actual SOC, sometimes not. Hopefully Rivian provides detailed info.

Mercedes (and a few others) have implemented predictive algorithms into some of their PHEVs. When you put your destination into the nav system, it will take into account speed limits, traffic, and terrain when deciding on the gas/electric choice (biased towards electric in town and at lower speeds). No reason this could not be implemented in all BEVs as a range estimate. Wouldn't be hard to tie into the National Weather Service/NOAA info as well (if my irrigation controller can do it, vehicles should be able to as well).

 

[ajdelange]

Math is just as easy for others.

Well it is for me and perhaps for you. I don't need the Monroney sticker mod. But apparently the public has trouble with mpg. What is really of interest is the amount of fuel/energy needed to operate the car i.e. how much one is going to have to pay for this energy for a particular distance traveled. L/100km, gpm and Wh/mi are covariant in the parameter of interest. Mi/wh, mpg and kwm/L are contravariant. This may be at the root of it.

What is most convenient depends on the application. With resistors it is convenient to work with the resistance if considering series circuits but conductance is more convenient if paralleling. For fuel management problems the covariant scale is more convenient.

 

[ajdelange]

http://www.mpgillusion.com/p/what-is-mpg-illusion.html

 

[ajdelange]

In hot weather, the EPA range is probably going to be fairly accurate. In cold weather, you will see a lot less range.

Tesla drivers overall see average consumptions that translate to 83% of EPA range in winter and 97% in summer. That's data collected over the subset of owners who subscribe to Stats. As far as what you might experience in terms of variation I (IOW no ensemble - just me so consider this example rather than statistic) have found in looking at my drives a CV (ratio of standard deviation to mean consumption) to be 28%. That corresponds to approximately 22% in range.

One really shouldn't speak of the EPA number as being "accurate". It isn't an estimate. It is a parameter descriptive of the vehicle when subjected to a specific measurement protocol. It is meant to be used in relative comparison of vehicles. It is only representative of what you may expect on the road. How representative depends on the road conditions and on the driver.

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