The idea that extra battery capacity is “dead weight” is a common misconception that belies a common ignorance about the electrical and chemical properties of batteries.
For a given chemistry and power and voltage, doubling a battery’s capacity will halve the battery’s internal resistance, thus improving its charge and discharge efficiency (as well as increasing the maximum charge and discharge power). It also halves the “C-rate,” thus allows it to last more cycles… and because the size is doubled, the number of miles per cycle also doubles. You can also afford to operate the battery with much larger margins, in its optimal state of charge, going from 75% to 25% state of charge, instead of hammering it from 100% to 0% (which would quickly wear it out, not even counting the difference in C-rate).
Sure, this still needs to be balanced with weight and cost, but a larger battery than you strictly need is NOT, in any way, merely “dead weight” in the way the ICE engine and fuel tank is in a PHEV like the Volt when I drove it for 6 months at a time while never using the engine.
For a given chemistry and power and voltage, doubling a battery’s capacity will halve the battery’s internal resistance, thus improving its charge and discharge efficiency (as well as increasing the maximum charge and discharge power). It also halves the “C-rate,” thus allows it to last more cycles… and because the size is doubled, the number of miles per cycle also doubles. You can also afford to operate the battery with much larger margins, in its optimal state of charge, going from 75% to 25% state of charge, instead of hammering it from 100% to 0% (which would quickly wear it out, not even counting the difference in C-rate).
Sure, this still needs to be balanced with weight and cost, but a larger battery than you strictly need is NOT, in any way, merely “dead weight” in the way the ICE engine and fuel tank is in a PHEV like the Volt when I drove it for 6 months at a time while never using the engine.