Hypothetical Melding

tiger955rider said:

If you could take the drive train of the Gen II Volt and the battery capacity of a P100D and put them together what kind of electric range would you end up with factoring in the extra weight, the efficiency of the volt drive train, etc?

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What kind of car are you putting it in? Range is affected at least as much by the load side (weight/rolling resistance, aerodynamics) as it is by the powertrain itself.

The Suburban version a few folks are proposing based on the size/weight of what you asked for wouldn't get nearly as far as either of the source cars, because it's a huge heavy car with fairly poor aerodynamics (hard to make bricks slippery, I'm sure GM is doing the best they can with it.)

It's also not the way I'd design an extended range car with ~90 kWh of usable energy - I'd use a much lighter, more compact generator in series that's only intended to match the steady state load, and on the rare occasions where it gets used, I'd hold on to a bigger buffer (4 kWh?) to handle acceleration and hill climbing. Sorta like the i3 REx approach in principle, but without the limitations that make the i3 so frustrating.

Since we're doing this by kitbashing at the moment, that'd also let me hang on to the Tesla drive motors and all that glorious torque and acceleration. (depending on the size/weight of the final car, of course.)

llninja said:

At a minimum, I think it would be nice if GM offered different sized batteries to volt and bolt owners so people can right size for their commute plus upgrade later if their commute changes. So someone who lives 5 miles from work can get a 20 mile EV range volt using only the center console part of the battery at a much lower price point. Then folks like me with a daily 65 mile commute would opt for the super pak to get 80 miles or so of range, filling additional space around the rear axle area of the volt.

I like the faraday futures' concept of adding additional battery packs as the wheelbase increases in length.

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Interesting. A couple of challenges - smaller packs mean less available power unless you stress the cells more, and with the large cells GM/LG Chem are using they only have a couple size options without changing either the cells or the pack voltage.

With Gen2's 192 cell architecture, you'd pretty much have to make it a 9.2 kWh 96 cell version to avoid affecting all the voltage targets - possibly 28 mile EPA given the lighter weight and half the available energy?

The part that I think would make that a hard sell is that it'd also only have ~65 kW of maximum power on battery (assuming the cells aren't able to do more than they are programmed to in the current cars) - similar to the Energi twins. (The obvious alternative is to make the smaller packs out of a power oriented chemistry instead, but that reduces the weight savings and forces additional engineering costs.)

Of course, you'd want to make complete integrated packs at each size rather than add on packs - that lets you keep cooling and BMS functions integrated and avoids having multiple series strings in parallel or duplicating service disconnects and contactors.