NAV battery/ Actual Battery estimate issue?

[jkspup22]

All,
I need some help understanding the estimated range and remaining battery life on my R1S.

I live in Massachusetts and have a house in VT. I made this trip this week which is 220 miles one way. I had assumed that If I charged to 100%, or 341 miles, I would be able to drive direct to my house and charge there. I adjusted my desired range in arrival to 20 miles. I was very surprised that it told me I wouldn’t be able to make it without charging. I understand loss, but a 120 miles seems excessive. On the way up I stopped at a charger that was 70 miles from my home, and I had 140 miles left on my battery. So again even when I was 70 miles out I would lose 70 miles? Seems excessive? I charged anyways.

side note, it’s almost all highway and I use cruise control at 70-72 for most of the trip.

On the way home I did the same charge stop. When I charged I had 246 miles on my battery with 146 miles remaining on my trip. My NAV said I would arrive with 20 miles left on my battery. Again 80 miles lost? Seemed excessive.

when I was about 100 miles out, the remaining battery on arrival jumped from 20 to 46 and by the time I pulled in, it sat at 78 miles.

So a long winded question. Why does the nav seem to project incorrectly and what can I do to get a true picture of how much battery I need. I’m not an expert, but I would assume on a 341 mile full charge I would be able to go 220 miles without charging. The simple answer is to just try the trip without stopping but before I do that I want to see if I am missing something that would cause me to get stranded?

thanks

Sponsored

 

[LL75]

That doesn't sound right. I take a 200 miles trip often from Dallas to Norman. It is mostly highway and the rivian is very spot on if I do 70 to 75 Mph. When I do 85 Mph, I lost about 25 to 30 miles prediction. Lots of factors involved. Speed, weather, wind.

Rivian needs to better incorporate abrp into their system instead of thru the app. It kept telling people to charge u necessary

 

[ThumprMN]

I’m learning the estimation calculation it makes isn’t accurate. I’m on a road trip right now planning every leg of my trip. I find it ends up with more range than it tells me I will have. I suspect this will tighten over time when they dial it in with software updates.

Case in point. I drive from Grand Junction CO to Salt Lake City yesterday. I was in conserve, on 21” wheels, and always drove the speed limit or below (for max MPG). I used ABRP app to plan my routes (which also underestimated range) and it had me stopping twice at lvl 3 chargers to get me there with 20%+ miles of range. When I fed that into Rivian, it would NOT let me get there without adding a third stop at a lvl 2 charger that added 1.2 hours of charging. No matter what I tried to change in the settings, it insisted I stop at some small town for a lvl 2.

I decided to wing it and see if I could make it without the lvl 2 portion. Kept watching my battery percentage and efficiency (going up /down mountain passes. I indeed made my trip with extra mileage to spare and I even cut my second charge short to save time and still ended up at my final destination with more charge than anticipated (est was 60 on arrival, got there with 109miles)

 

[gvtucker]

It's frustrating, no doubt. I'm in North Carolina, and frequently take trips to the coast, about 160 miles. After a bit of experimentation, I've figured out that as long as I have 200+ miles of range, I can make it there, driving about 80 mph the whole way. In colder weather and/or rain, I'll make sure I have 220+ of range. The NAV thinks I need 240 miles of range.

 

[SANZC02]

It is hard to calculate because of wind, terrain, and speed. Over time you will get a pretty good feel for what the range will be. The flatter the trip the easier to calculate, I find mine to be pretty good most of the time and the navigation estimate when a route is active seems to be more accurate than the dash reading, it also adjust while you are progressing.

 

[Riviot]

Don't worry, folks...

You're lacking a lot of info, like drive mode/height, battery departure temp, vertical gain, temps, conditions, tire psi, wheel/tire type/size...

Peruse the forum for a week or so, read some write-ups on road trips, and report back with necessary information and your findings!

 

[jkspup22]

Riviot,

All good points. I’m using the 21inch road tires. Colder weather conditions 20-40 degrees, ride height low, and dual motor all purpose. Tire pressure is normal(don’t remember exactly what it is).

Given I am driving north it is a bit up and down but not mountainous like our west.

I guess my overall issue with all of that being said is how off the calculation seems to be and is there anything I can do get a better calibration? Using my trip home as an example, when I charged it said I would only have 20 miles left even though I had 100 miles more on the battery vs what the GPS said. So 80 miles lost seemed VERY high for a 146 mile trip.

adding confusion is I ended up with almost 80 miles left vs the quoted 20 miles. So using simple math, on the 146 mile trip, I lost 20 miles due to conditions not the original 80 quoted.

 

[Craigins]

The nav miles remaining estimate has always been garbage for me. The miles remaining by the battery indicator on the driver's screen is accurate for me. I typically just do the math manually between the 2 systems. As you noted, when you get close to your destination the nav calculations readjust and end up "accurate" but that is meaningless at the start of your trip.

I have launch edition r1t and drive in all purpose/low on 20"s. Terrain is pretty flat, WI and IL.

Another thing to watch out for is the nav trying to force you to a charger and then start preconditioning, wasting even more energy. I've had to disable the nav because of this. It didn't think I could make it to my destination after charging (100mi to destination, 170mi of range, speed limit of 55 for most of it). As soon as I left the charger it tried to reroute me back to continue charging. So annoying.

 

[mkg3]

I only use the route planner to gain actual miles to the destination. Often the charge number and stops are inaccurate. For an example, I drove 250ish miles between the charge and the Rivian nav told me that I had to stop for 15 min charge around 150 miles into the drive. My arrival range remaining is set to 30 miles. I made it just fine with almost 50 miles remaining without the stop. This behavior has happened time and time again on other road trips.

So I essentially ignore the Rivian nav plan.

That said, cold weather will make a big hit, along with the elevation changes. Rivian does not have a heat pump so the loss can be significant in low temperatures between the battery not warming up to optimal temperature and use of heater in the vehicle. The winter degradation can be near 50% depending on the conditions.

You now have data point from your recent trip in the winter. The same trip in the summer will show a quite a different result.

 

[atrieger]

I had a tesla for 3 years, now proud Rivian owner. Tesla had this figured out easily, I'm sure rivian will get there, it's likely about 1 day's coding time and an update pushed to everyone.
I suspect they're simply not using the actual average power used while driving for nav estimates, or they are on the dashboard but not elsewhere (as someone above noted that was accurate).

Tesla, fwiw, has an energy screen, you can look at 5min, 15min or 30min chart. Whichever you set, it uses that average and the distance from destination to figure out battery usage and it's spot on. It will change as you change driving habits (go up a mountain, run the heater a ton, get a big tail wind). Safest is 15min or 30min chart of course.

Rivian can do the same thing, they already have an energy display in the dashboard, left side, for 15 min energy use and average (rivian does miles / kwh, tesla does kwh/mi, just inverse of each other).

Anyway, to answer your question, until Rivian fixes this bug, you could calculate the average efficiency you need to make it there and then just make sure you're always averaging more than that.

220 miles to the house.
Does your r1s have 135 KWH battery? lets pretend it does.
To get there with 20% (27kwh) left, if you start at 100%, you need that average to be above 2.04 miles/kwh the whole way basically.

After a few months, years, the battery will never work at 100%, so say its really only 90% as good as it was new, so total is .9 * 135 = 121.5 kwh usable capacity.
You need to go 220 miles. You're ok using 80% to get there (97.2 kwh).
So you want the miles / kwh average to always be above: 220 / 97.2 == 2.26 miles/kwh.

This will take into account everything, wind, road type, speed, towing, wheels, heat use... because if all that is horrible, your real time energy use will be poor but as long as its averaging over 2.26 you're fine.

If you're not fine, the most efficient speed is <50mph and the heater off (if it's winter). Only in an emergency of course, but wind speed over 50 is a significantly increasing drag and heater power as temps drop to 20, 10, 0 degrees are also.

Once rivian uses this number instead of whatever they're using in their nav calculations then it'll work like tesla's do which I found very useful and accurate because it updates live.

I was driving once and the wind changed, by a lot, head wind, 20mph, and without changing anything my battery at destination went from 20% down to 0% and negative and of course the tesla told me I would need to stop and charge and found a place, which rivian can do too. In this particular instance I slowed way down cuz I didnt like the wind anyways, the efficiency went up enough that the battery at destination went up to 2% and I held it there and it was spot on .

oh course we shouldnt have to do math to take a trip but I'm sure rivian will fix this and use the realtime-weighted-average energy usage while driving to constantly update the battery at destination figure. And the tesla supercharger adapters coming out soon will certainly help too.

Sponsored