In article 529e2675-f8de-4c10-b09c-9b2bedc19cb6@
29g2000prb.googlegroups.com, says...


err... you house is 110 VAC and the boat is 12 VDC. Your 200 amp load
center is handling 110 X 200 = 22 KW (approximately) while the boat is
handling 12 X 250 = 3 KW.

Cheers,

Bruce


Hello Bruce:

Yes you and et al are totally correct. I aplogize deeply for my quick
read of the original post and mislead reply. After 4 beers and a
quick look at his post I though the guy was going to hang an AC 110V
generator off his main. So at face value of my post I must apologize
for a seemingly ignorant rant. But to be honest most the times the
problems guys here seek guidance are off on the wrong foot to begin
which leads them down a path of frustration, expense, loss of
reliability, added complexity, and compromised safety.

Time for me to cross my legs and ask for that last spike. Crucify away
gentle men, I am guilty of not giving a member of RBC a sincere read.

Even still............. do you actually believe a boat 45' should
consume that many amp/watts ??? I still say that its either time he
reduced his amp consumption or get a larger vessel capable of
providing the volume to support that kind of load,,, as in a dedicated
gen set.

Based on my experiences in some of the inlets of British Columbia, I
would greatly prefer cruisers to have the alternator and battery
capacity to avoid running a generator while at anchor.

I try to practice what I preach. On a 21-day cruise this summer from
Ketchikan to Bellingham, we only used the genset to charge the
house batteries about 3 times. We didn't watch TV or use the microwave
too often---except the night the propane tank ran out. ;-) (Propane is
hard to find between Desolation Sound and Nanaimo.)

We also had the benefit of quite long daily runs to get the
house battery charged. It was the days where we ran only 3 or 4 hours
that required the most attention to power management.


If you look at a worst-case short cruise as four hours of engine time,
then you can charge at 200A for 4 hours. That will put about
160AH back into your batteries for later use.

160AH x 12V = 1,920KWH.

From that, you have to subtract running loads---which can be
considerable if you have the radar and chart plotter on
for four hours.

Let's say you have 1600KWH in the battery bank to keep you
going for the 20 hours the engine is not running.

In the summer, you may be up and about for 12 hours
in addition to the running time.

1500KWH/12 = 133 Watts per hour.

125 Watts isn't a lot if you're going to recharge all your
portable electronics and keep the sounder on for comfort's
sake. (We probable keep the depth sounder on more often in
the Northwest with 20+ foot tidal ranges.)

Investing a thousand dollars or so in LED interior lights
is probably the best way to cut the AH budget. After all
each of the old-style incandescant lamps was about 15-20 Watts.
Reasonable cabin lights alone could be 150 Watts.

Mark Borgerson

Based on my experiences in some of the inlets of British Columbia, I
would greatly prefer cruisers to have the alternator and battery
capacity to avoid running a generator while at anchor.

I try to practice what I preach. *On a 21-day cruise this summer from
Ketchikan to Bellingham, *we only used the genset to charge the
house batteries about 3 times. * We didn't watch TV or use the microwave
too often---except the night the propane tank ran out. *;-) *(Propane is
hard to find between Desolation Sound and Nanaimo.)

Mark Borgerson


Mark:

What abandonship equipment do you carry when traveling those waters?

Have you talked with the local USCG station regarding their rescue
procedures and vessel responibilites? Have you took a tour of their
facility or started one of the portable rescue pumps?

This isnt a troll Im actually sincerly interested. Very few people
operate where you do...... For obvious reasons. Its not called the
grave yard of the Pacific for nothing.
Bob

In article ,
Mark Borgerson wrote:

If you look at a worst-case short cruise as four hours of engine time,
then you can charge at 200A for 4 hours. That will put about
160AH back into your batteries for later use.

160AH x 12V = 1,920KWH.

From that, you have to subtract running loads---which can be
considerable if you have the radar and chart plotter on
for four hours.

Let's say you have 1600KWH in the battery bank to keep you
going for the 20 hours the engine is not running.

In the summer, you may be up and about for 12 hours
in addition to the running time.

1500KWH/12 = 133 Watts per hour.

125 Watts isn't a lot if you're going to recharge all your
portable electronics and keep the sounder on for comfort's
sake. (We probable keep the depth sounder on more often in
the Northwest with 20+ foot tidal ranges.)

Geez Louise, are all the folks in this NewsGroup math retards?

if you have 160 AH @ 12 Vdc that is 1920 WATTHours, NOT 1929 KWH...

Duh.... Your only off by three orders of magnitude....

In article 82d50844-25c3-44b9-9722-
, says...


Based on my experiences in some of the inlets of British Columbia, I
would greatly prefer cruisers to have the alternator and battery
capacity to avoid running a generator while at anchor.

I try to practice what I preach. *On a 21-day cruise this summer from
Ketchikan to Bellingham, *we only used the genset to charge the
house batteries about 3 times. * We didn't watch TV or use the microwave
too often---except the night the propane tank ran out. *;-) *(Propane is
hard to find between Desolation Sound and Nanaimo.)

Mark Borgerson


Mark:

What abandonship equipment do you carry when traveling those waters?


We had an outboard RIB dinghy which could be launched very quickly.
There is an abandon ship bag with portable VHF, GPS, space blankets,
flares, and some other safety equipment. We always had life jackets or
float coats in the cockpit, as we needed them each time we used
the dinghy. The boat also has an EPIRB.

Have you talked with the local USCG station regarding their rescue
procedures and vessel responibilites? Have you took a tour of their
facility or started one of the portable rescue pumps?

On our trip from Ketchikan to Bellingham, there were probably a
dozen local coast guard stations, both Canadian and US. I didn't
talk to any of them on this trip, nor did I visit their
facilities. I have talked to local coast guard personnel and
visited stations here in Oregon. The BC trip was on a charter
boat, so I didn't expect too much beyond standard safety gear.

http://www.sanjuansailing.com/charte...ment/index.htm


I haven't run a P250 pump since my Navy DC training, but I have
lots of experience with portable generators and other small engines
comparable to those on the pumps.

This isnt a troll Im actually sincerly interested. Very few people
operate where you do...... For obvious reasons. Its not called the
grave yard of the Pacific for nothing.

LOL! There are thousands of boaters in the Pacific Northwest.
There are probably as many charter boats in BC as there are fishing
boats these days---commercial fishing having seen better days.

The 'Graveyard of the Pacific' more properly applies to the
coast from Tillamook Bay in Oregon to Vancouver Island. Pleasure
boating along that coast is primarily a fair-weather activity
in bays and rivers, with occasional fishing trips outside
the bar. The lack of harbors and the inhospitable entrance
bars on those that do exist are the reason that I do most of my
pleasure boating in the protected waters of Puget Sound, the Gulf
Islands, and Desolation Sound.

On the most open-sea part of our voyage--crossing the Hecate
Strait to the Queen Charlotte Islands we didn't see any other
pleasure boats, but were passed by a few cruise ships. At
the farthest out point, I think we were about 30 miles from
either shore. Most of the trip along the inside passage, we were
generally within 2 miles of land. Once back along the inside
passages, we saw lots of pleasure boats---although not with
the density you find in Desolation Sound, the Gulf Islands,
or the San Juan Islands. In those places, in August, you'll
seldom have an anchorage to yourself, as we did along the
inside passage.

Mark Borgerson

In article ,
says...
In article ,
Mark Borgerson wrote:

If you look at a worst-case short cruise as four hours of engine time,
then you can charge at 200A for 4 hours. That will put about
160AH back into your batteries for later use.

160AH x 12V = 1,920KWH.

From that, you have to subtract running loads---which can be
considerable if you have the radar and chart plotter on
for four hours.

Let's say you have 1600KWH in the battery bank to keep you
going for the 20 hours the engine is not running.

In the summer, you may be up and about for 12 hours
in addition to the running time.

1500KWH/12 = 133 Watts per hour.

125 Watts isn't a lot if you're going to recharge all your
portable electronics and keep the sounder on for comfort's
sake. (We probable keep the depth sounder on more often in
the Northwest with 20+ foot tidal ranges.)

Geez Louise, are all the folks in this NewsGroup math retards?

if you have 160 AH @ 12 Vdc that is 1920 WATTHours, NOT 1929 KWH...

Duh.... Your only off by three orders of magnitude....

Ooops, Sorry about that, The 1.920x10^3 WH on my HP Calculator
suffered a typo in transcription and became 1,920KWH.

I then managed to carry the K throughout the rest of the
calculations. DOH! I should know better than to try
such calculations before my morning caffeine dose!

It's good to see that someone is actually checking the
math.

At least I think I arrived at the proper conclusion----that
you only need to use about 133 Watts continuously to require
quite a large alternator to recharge your house bank in
4 hours. In tropical waters, you might reach that load on
refrigeration alone---particularly if you want ice in
your cocktails! ;-)

Mark Borgerson

On Mon, 15 Nov 2010 13:33:33 -0800, Mark Borgerson
wrote:

At least I think I arrived at the proper conclusion----that
you only need to use about 133 Watts continuously to require
quite a large alternator to recharge your house bank in
4 hours. In tropical waters, you might reach that load on
refrigeration alone---particularly if you want ice in
your cocktails! ;-)

There are lots of good reasons for having a large alternator but it is
almost impossible to fully recharge your house bank in 4 hours if it
has been drawn down to any great extent. With any luck you can get
through the bulk stage however to the 80 or 90% level.

In article ,
Mark Borgerson wrote:
Ooops, Sorry about that, The 1.920x10^3 WH on my HP Calculator
suffered a typo in transcription and became 1,920KWH.

I then managed to carry the K throughout the rest of the
calculations. DOH! I should know better than to try
such calculations before my morning caffeine dose!

It's good to see that someone is actually checking the
math.

At least I think I arrived at the proper conclusion----that
you only need to use about 133 Watts continuously to require
quite a large alternator to recharge your house bank in
4 hours. In tropical waters, you might reach that load on
refrigeration alone---particularly if you want ice in
your cocktails! ;-)

Mark Borgerson

Thats OK, Mark... Are you planning to come back North next spring?

In article ,
says...
In article ,
Mark Borgerson wrote:
Ooops, Sorry about that, The 1.920x10^3 WH on my HP Calculator
suffered a typo in transcription and became 1,920KWH.

I then managed to carry the K throughout the rest of the
calculations. DOH! I should know better than to try
such calculations before my morning caffeine dose!

It's good to see that someone is actually checking the
math.

At least I think I arrived at the proper conclusion----that
you only need to use about 133 Watts continuously to require
quite a large alternator to recharge your house bank in
4 hours. In tropical waters, you might reach that load on
refrigeration alone---particularly if you want ice in
your cocktails! ;-)

Mark Borgerson

Thats OK, Mark... Are you planning to come back North next spring?

The three-week trip in August used up my charter budget for a couple
of years. I suspect that I'll only be doing armchair cruising until
the kids get out of college.


Mark Borgerson