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posted to rec.boats.cruising
Larry
 
Posts: n/a
Default boat AC/heatpump

Wayne.B wrote in
:

Rolls batteries typically last 7 to 10 years if well cared for. We
are *not* talking Walmart quality here. Most of the folks who buy
those beautiful little Duffy boats are old enough that 7 to 10 years
is as good as a lifetime warranty.



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?!

Pouring out 180 amps from a plastic cased lead-acid battery, subject to
physics and chemistry no amount of advertising hype can contradict, I
submit there's no way a Rolls sooper-dooper battery will survive 7 years
of this abuse, which amounts to connecting your Rolls house batteries to
the starter motor and driving home without diesel fuel every time you run
the boat.

I'd love to test this theory if Rolls is willing to fund the Duffy and
$14,000 worth of Rolls batteries for an honest test, however. LET THE
DEEP CYCLING BEGIN!

I see the accessories all run off yet another $900 house battery. I
didn't add that figure in because every boat has those.

The damned battery supplies from anywhere seem to go flat when someone
shows up with the simplest calculator and ohms law asking embarrassing
questions why the 4KW inverter can't run 2 ton of air conditioning off
$15,000 in batteries....(c;