Max Pack chemistry and quad motor

[pc500]

So I'm still looking into this, but I received information that Rivian went with a ~5200mah Samsung 21700 cell for max pack. Whereas their large pack is based on a 4800mah Samsung 21700 cell. I'm not sure how to do the math on that, but reading elsewhere here on the forums, I think that would make the max pack 146kwh vs large pack 125kwh usable. Someone feel free to correct my math. My concern has been slightly abated now that we know the cell isn't operating at the bleeding edge of theoretical cylindrical cell technology.

This may very well be true, but in that case why didn't they offer it on the quad? Ugh.

Sponsored

 

[Supratachophobia]

This may very well be true, but in that case why didn't they offer it on the quad? Ugh.

Because then they'd never ween anyone off quad. And they aren't ready to do in house quad motors (quad Enduro). That, and the product differentiation wouldn't be enough to compel people into higher margin vehicles. It's all business because it has to be.

 

[Zoidz]

...

Again I can only speculate but based on Rivian's statements I don't think they are using different hardware because they are going for simplification so they can pump out more units and get the cost down while also increasing their margins.

...

According to the EPA submission, the Front Drive Unit (FDU) of the Dual Motor has a lower axle ratio than the Quad motor. This means the Dual Motor will be more efficient than the quad motor. Just comparing cell capacity isn't going to tell the entire story.

 

[pc500]

According to the EPA submission, the Front Drive Unit (FDU) of the Dual Motor has a lower axle ratio than the Quad motor. This means the Dual Motor will be more efficient than the quad motor. Just comparing cell capacity isn't going to tell the entire story.

We know that, even before the quad. Supposedly, the dual max pack is more efficient than dual large pack, according to some people anyways.

 

[HaveBlue]

The max would have a lower C rate per cell and that helps extract more power with less going to heat and resistance. In other words, there is an optimum drain rate to extract the rated power. Draw faster and you won't get everything out. Drawing the same rate from a pack with more cells means each cell loses less.

The front drives seem the same between the dual and quad for efficiency. The quad in conserve has the same range. Wind resistance is likely the dominant factor.

 

[Zoidz]

We know that, even before the quad. Supposedly, the dual max pack is more efficient than dual large pack, according to some people anyways.

I'm specifically referring to efficiency boost by the lower drive ratio in the Enduro hardware. From the comments above about any hardware differences, it's clear that many people don't this ratio contributes to the higher efficiency.

 

[Supratachophobia]

I'm specifically referring to efficiency boost by the lower drive ratio in the Enduro hardware. From the comments above about any hardware differences, it's clear that many people don't this ratio contributes to the higher efficiency.

Just from my limited experience in EVs, I can't imagine that chip makeup, C rate, battery size, individually adds up to any real "butt" measurement, especially in short trips. It's the mechanical changes like drive ratios or lack of drag from a disconnected rear drive train that will make the differences we notice the most. As many have said, I don't yet think we have the full answer yet. Although, I will say that someone close to the situation told me that they would opt for the max pack based on it's merits. So there's enough of a difference going on besides raw range/capacity. So maybe we'll be surprised by some type of charging improvements, who knows.

Where the hell is Kyle with a max pack when you need him......

 

[vandy1981]

According to the EPA submission, the Front Drive Unit (FDU) of the Dual Motor has a lower axle ratio than the Quad motor. This means the Dual Motor will be more efficient than the quad motor. Just comparing cell capacity isn't going to tell the entire story.

The inverter on the Enduro front motor also uses silicon carbide which apparently provides some additional efficiency gains.

 

[Supratachophobia]

The inverter on the Enduro front motor also uses silicon carbide which apparently provides some additional efficiency gains.

Right, but again, is this raw "butt" efficiency? I have no doubt it helps, but is it's change alone enough for us to notice and if so, why not on the rear as well?

 

[vandy1981]

Right, but again, is this raw "butt" efficiency? I have no doubt it helps, but is it's change alone enough for us to notice and if so, why not on the rear as well?

SiC is more expensive. The front motor doesn't disconnect so it makes sense to use it there. I have no idea what you mean by butt efficiency. I don't think the human sensorium can differentiate between 3.0 mi/kWh and 2.0 mi/kWh. That's why there is a trip computer.

 

[Supratachophobia]

SiC is more expensive. The front motor doesn't disconnect so it makes sense to use it there. I have no idea what you mean by butt efficiency. I don't think the human sensorium can differentiate between 3.0 mi/kWh and 2.0 mi/kWh. That's why there is a trip computer.

Butt Efficiency = a change in efficiency that is noticed and can't be attributed to the obvious contributors of wind/speed/temp/precipitation.

In other words, something statistically significant.

 

[vandy1981]

Butt Efficiency = a change in efficiency that is noticed and can't be attributed to the obvious contributors of wind/speed/temp/precipitation.

In other words, something statistically significant.

We'll need some head-to-head testing for that, I guess.

 

[HaveBlue]

Indeed they are trying to sell something at an exceptional premium that no one has tried. All we have is a price and a range number to analyze. I might have jumped on the max had it only been $5K more but this is really just to much for a return that won't decrease the number of charging stops on a longer trip, (especially when towing).

Sponsored