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The Natural Philosopher

wrote:
Slurp wrote:

Without picking through your figures, you probably are right. Max speed
is about power to drag. So going fast is very energy inefficient.

Picking through the specs, the vehicle weight is not quoted,and
acceleration is power to weight - so that'll be another battery-eater.

So that 250 mile range probably requires gentle acceleration and
moderate speed - but there are no concrete figures for the test
conditions - so we don't know.

On the plus side it quotes 1000lb for the battery pack weight, and it
sounds like it's using a single electric motor through a conventional
powertrain. Lotus make a light car - so maybe around a ton kerbweight?
And people from the electronics sector do know a few things about power
management - they're used to doing everything possible to get the most
out of a battery.

That many Li-ion cells must be a large proportion of the price - I
wonder if you get good quality or even hand-matched cells? And how long
before the battery pack has had enough and requires replacing?

Indeed. All valid points.

the discharge rate is not excessive - anything over 20 minutes-to-flat
is not a huge stress for a lithium cell, and that means they can be
optimised for low self-discharge and decent cycle life. At least 100
cycles (20,000 miles) is EASILY obtained, and 500 cycles (100,000 miles)
should be within reach. You wouldn't necessarily need hand matched
cells. The way I'd do it is create plug in blocks each with a
voltage/current/temperature monitor on them feeding a data bus, and
switch em in and out as they got flat, or near overcharging, or too hot etc.

Then at service time, any substandard blocks get swapped out.