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posted to rec.boats.cruising
Wayne.B
 
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Default boat AC/heatpump

On Fri, 23 Jun 2006 15:12:59 -0400, Larry wrote:

Running sailboat lighting, the stereo and some electronics with the
intermittent load of the bilge pump and inverter is a far cry from
running a 20 horsepower DC propulsion motor pulling a large boat at 8
knots, discharging the hell out of the Sooperbatteries in the process.

Guessing, using the standard 846 watts/hp, 20hp = 16,920 watts divided by
the 96 volts all the series batteries produce = 176 (and change) AMPS if
you're running it at 8 knots, wide open. Wanna bet they get HOT?!


Your numbers are off a bit. Around here these things get driven by
little old men and ladys around the canals for a few hours on Sunday
afternoon when the grand children are visiting. Average speed is
probably about 5 kts which requires no more than 3 or 4 hp with an
easily driven hull.

Figure 4,000 watts give or take, around 40 amps, no heat generated, no
animals killed, injured or abused. After 3 hours the batteries are
still at greater than 50%. These things do not get taken off shore.

:-)