On Mar 21, 4:37 pm, Richard Kollmann
wrote:
It is interesting to know how other boaters are selecting equipment
and managing electrical power on cruising sailboats. Standard
production sailboats rarely have onboard DC power grids to support
additional electrical loads. Most extended cruisers and live aboard
boaters prefer to have conveniences like refrigeration microwave
ovens, computers and creature comfort items. There must be a limit to
how much daily electrical load that can be supported on a pleasure
size extended cruising sailboat, but what is this limit? I believe
that an average cruising boat's DC power consumption when at anchor
might be at least 50 amp-hrs per day. If equipped with refrigerator
add 10 amp-hours per cu. ft. of box per day. If additional 110 volt
appliances are powered from an inverter the total power grid will be
overstressed unless energy is generated from other than the a engine
alternator.
(clip)

If you are following Skip's Morgan 46 adventures on Flying Pig you
know his plan was to support all his electrical and refrigeration
needs including heating water with 12 volt energy. Skip removed the
engine driven refrigeration system replaced it with a 12 volt
Frigoboat unit. The large generator was removed providing room for a
battery bank. We are still not sure what his actual daily power needs
are but he seems to be managing his energy budget by trimming down the
load and running a small Honda generator when wind and solar power is
not enough. One good piece of information Skip provided if I
understand him correctly is the Hondo 2000 powering a 40 amp DC output
charger can rum 6 hours on 1/2 gallon of gas. I have a 3000 watt
generator that consumes 6 gallons per hour.

Hi, Guys,

Larry's observations about my genset are accurate. I don't know where
you got my consumption figures, Richard, as I thought I'd indicated
that my typical run was ~6 hours per tank when charging and doing
other miscellaneous stuff. That's vs, for example, heating the hot
water tank, which I would never ask the inverter to do, a full-
throttle run, but only for about 15 minutes of the time in a recharge
cycle. The normal recharging run has all the "normal" inverter (no
mikey, no heat gun, no hair dryer) items like computers, handheld and
"dry cell-type" battery recharging, etc., at the same time as
recharging the house; the water heater is typically reheated at the
same time, but the charger turned off for that period.

OTOH, if we forget to turn off the charger, the combined loads is more
than the Honda can handle, and the overload kicks it off. That is, no
power is delivered; the engine continues to idle. The cure is to
cycle the on-off handle until the red light goes out and turn it back
to "on" where it kicks in again. So far, we're very happy with it. It
and the dedicated fuel can live in the cockpit, under Sunbrella
covers, and right next to the scupper drain in the event of leak or
fumes, in a space which might well have been designed for it, the
fit's so good :{))

Meanwhile, I've been wondering if you have some easy, inexpensive,
means of actually tracking the AH usage, both for the reefer and as a
whole. The TriMetric may have such a function overall, but I don't
really know how to separate it on a daily or timed-period basis, and,
of course, not for the reefer. It would also be interesting, but not
something I think I need to have on a permanent basis, to know the
number of cycles the reefer compressor has per day. Ideas on all
that?

Finally, because of the above, I really don't have hard numbers on the
usage, but the individual loads were carefully measured (or as
carefully as a nothing-else-running measure with the decimal amps
readout of the TriMetric) per device, so I'm pretty confident in the
numbers I presented, and in the time of usage per device. If I'm
reasonably accurate in those, the AH daily use should be pretty close.

For all that, as noted, in sunny and breezy conditions, we are fully
supplied for our usage. So far, the Honda supplement has proven
acceptable, though I'd far rather not have to use it other than for my
Hookah rig or other high demand tool-style times. Certainly, though,
offsetting that, I don't believe I want to run 1500 watts for even 15
minutes from the inverter - unless it's blazing and howling outside! :
{)) - to make hot water, so, for passages, it appears we'll be using
that at least occasionally.

Thanks for any pointers to gear for measurement...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
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