For the benefit of the newbies - a couple of minor corrections
if I may, mainly about AC motors and non lead acid batteries:
Martin Jackson wrote:
...
> Motor rpm is limited by available
> Voltage.
That applies to DC motors. Less common AC induction motors RPM is
dictated by the frequency generated by the inverter.
Motor power is limited by the max rpm and heat loss
> (kW * {1 - efficiency}) balanced against fan effectiveness.
Some motors have no fans
> While the
> industrial motors are rated (will produce power) at a given rpm, the
> same torque can be delivered at higher rpm without wrecking the
> commutator
AC motors have no commutator and so no problems associated with it.
> and you can use over 5000 rpm on a 9 in. motor producing
> much more power than the manufacturer will claim. Many road EVs will
> cruise at up to 4000 rpm to help cooling where the ICE version uses
> 3000 rpm.
Usually AC motors can run up to 10,000 RPM and above because there are
no brushes or commutator. The limits are mechanical strength of the
rotor
and max frequency inverter can generate while providing needed power.
> Different batteries (types) have different internal resistance. Down
> to 50% State of Charge (SoC), the resistance is about constant.
That is for lead acid chemistry only.
> Range and power both suffer at low temperatures.
Again, depends on the battery chemistry. For instance for NiCd it's
exactly opposite of what you just said - they don't degrade at cold
temps but suffer when heated up. NaNiCl battery is not affected by
outside temperature at all as contained in the enclosure with its own
local "climate control".
> The above
> observations will generate several differing opinions and may not be
> totally accurate. This is about what I would do.
Martin, you did very good job, describing what a newbie will most likely
use for the first time. For the benefit of a newbies I just wanted to
make sure they're aware that other options with entire different
battery and drive train technologies and characteristics exist
(and to various degrees available now), whether suitable and practical
for them at the moment or not.
Victor
