Battery size: Gen 1 vs Gen 2

[beatle]

No way usable capacity is up on the Large when maximum ceiling is significantly down. Mathematically impossible.

Given the smaller large battery, efficiency would have to be 3.1-3.3 miles per KWh to get to the same 350 mile EPA range. Gen 1 posts here were pretty all clustered around 2.2-2.4 miles per. I have only seen one person post on a Gen and they stated they are getting 2.5 miles per KWh. More efficient but not enough to make up for a huge cut in battery top line capacity/size. Efficient up, range on large is going to be way down unless someone has 3.0 miles per efficiency over the course of driving conditions average.

I like the Gen 2 changes but trying to understand that range will come down hard on the Large pack. Without more data it seems undeniable.

If the efficiency story was that good wouldn’t Rivian market the heck out of that?

20" wheels are pretty popular, and 2.2 - 2.4 seems typical of a dual motor truck in the summer, though to make rated range you actually need 2.5mi/kwh. You can go further still with the 21" config, though you're also expected to get 2.9 mi/kwh to make rated range.

I don't know where the extra efficiency is coming from in the G2 trucks either since the motors and aero are the same. The heat pump is a nice thought for cold weather and can make a real difference in the drain required to heat the cabin, but it's not a silver bullet. Colder air is also denser and requires more power to push the truck through it. Perhaps the 22" "range" and 20" road wheel/tire configs are responsible for the bump? I agree that if there was a true 16% breakthrough in efficiency, Rivian would be leaning into announcing those to help market the truck's changes. Seems funny to me too.

Sponsored

 

[RexRemus]

Heat pumps just for heating. Wouldn’t do anything for cooling.

But dropping the battery size by 16% and equaling same range is a massive efficiency gain.

If that is real their marketing dept should be blasting out how much efficient their gen 2 is. But they aren’t. Feels off and incongruous. Why not talk about a good thing unless it isn’t.

I'm not sure you understand how heat pumps work - they absolutely heat AND cool

 

[E_Monkey]

I'm not sure you understand how heat pumps work - they absolutely heat AND cool

Yes but at less performance that’s the eff gain. Generally in housing if your in a hot climate pick a traditional AC if your in a cooler climate your most cost efficient and energy efficient option is a heat pump.

A heat pump is a conditinal solution it’s not best in all scenarios.

 

[usulio]

I was just looking at Out of Spec's range test results since they just posted a Gen 2 test (video below). They do the same route at the same speed (70mph) usually under very similar conditions. It is at altitude so sea level efficiency will not be as good, maybe 10% worse at a wild guess.

They got these results at 70mph at altitude. The Gen 1 R1T seems slightly more efficient than R1S but very similar results.

1. Gen 2 R1S Dual: 2.66 mi/kWh.
2. Gen 1 R1S Dual on 21": 2.52 mi/kWh
3. Gen 1 R1S Quad on 20": 2.30 mi/kWh

Videos:
Gen 2 R1S Dual: youtube.com/watch?v=ni2C5UUgGgw
Gen 1 R1S Dual 21": youtube.com/watch?v=bKl_Vz3K60I
Gen 1 R1S Quad 20": youtube.com/watch?v=HdD6ZdKo4RY

 

[usulio]

I think there are two big points that are not obvious. One is that the change in tires to Gen 2 could be giving most of the efficiency gains (others have guessed this as well).

Two is highway versus city driving. When people talk about range most people think about highway driving, but EPA and Rivian numbers are a mix. Maybe Gen 2 is quite a bit better than Gen 1 in the city but not much better on the highway?

One place this city vs highway shows up is the difference between battery packs on the same vehicle. Rivian's Gen 2 estimates correspond to 2.8 mi/kWh for the standard pack but about 3 mi/kWh for the large and max packs. That only makes sense to me if the large and max pack numbers have a higher percentage of city driving factored into the range estimates.

 

[emoore]

Yes but at less performance that’s the eff gain. Generally in housing if your in a hot climate pick a traditional AC if your in a cooler climate your most cost efficient and energy efficient option is a heat pump.

A heat pump is a conditinal solution it’s not best in all scenarios.

Most heat pumps in the US are in the southern states. They work just as well as a conventional AC in the summer.

 

[Singletracker]

Gen 1

An electric vehicle’s “usable capacity” is the portion of the battery dedicated to vehicle propulsion and cabin comfort – think driving, heating and air conditioning.

• Standard: 106 kWh
• Standard+: 121 kWh
• Large: 131 kWh
• Max: 141 kWh

Where do these useable capacity figures come from? Over time, I have heard everything from 128 kWh to 130+kWh for the large pack. So, I’m just curious - are these figures the real deal? I would like to think so. I‘ve always, optimistically, used 130 kWh for any calculations I have done, but I like 131 even better ?

Sponsored