Re: 42V Car Batteries
- From: "Ralph in NH" <ralph672@xxxxxxxxx>
- Date: Wed, 31 Oct 2007 00:42:15 GMT
"Winfield" <winfieldhill@xxxxxxxxx> wrote in message
news:1193745318.946628.245660@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Ralph in NH wrote:The electric part of a hybrid is more about torques assist than than total
Michael wrote ...
What's the reasoning behind the suggestion for upping the car battery
voltage to 42V? I would have thought it would make more sense to have
started with let's say 42Vwhen you have large loads - starter motor.
Then
start dropping it as cars have more electronics in them (ie lower
voltages
and loads).
Apart from the savings in copper usage, 4*42= roughly p-p voltage for
120VAC
rms. Although in another lifetime at Behemoth Oil Co we ended up using a
204 VDC battery pack to make decent 120VAC 0-400Hz (70kW 3-phase AC motor
for gas-electric hybrid vehicle). I wonder if any mainstream
manufacturer
will make the obvious leap to 120 volts.
My '07 Prius battery is 201.6 volts, according to their spec
brochure. It's rated at 21kW (28hp). But they say "Hybrid
System Net Power 110 hp (82 kW)" - this must include the
combustion engine, which is rated at 76hp at 5000rpm. They
also say: "Electric motor power output 67 hp @ 1200-1540 rpm
(50 kW @ 1200-1540 rpm)" which to me implies the battery can
deliver at least 50kW, rather than 21kW. Perhaps those two
numbers refer to peak power and average power? There's also
the matter of momentary pulses of power the motor delivers
in its function to replace a flywheel, which is missing.
Anyway, 50kW from a 200-volt battery implies 250A. I'd like
to clamp a current meter on the battery cable and take some
measurements. It's on my long list of things to do someday.
power. Horsepower (torque*speed) matters a lot when you're talking about
the difference between 120mph and 140 mph. Torque matters off the line,
where most drivers sense peformance. Things that offer low-end torque are
under-square big-block gas engines, diesel engines, and DC motors. AC
synchronous motors too, properly driven (basically a DC brushless
reassembled). Oh, and Grant's semi-right about 42VDC being a "safe"
voltage. I can picture UL waiting in the wings, rubbing its hands together,
just waiting to hold the auto industry hostage - I mean, go to the wall for
consumers :-)
.
- References:
- 42V Car Batteries
- From: Michael
- Re: 42V Car Batteries
- From: Ralph in NH
- Re: 42V Car Batteries
- From: Winfield
- 42V Car Batteries
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