On Fri, 10 Aug 2007 18:29:15 -0400, Jeff wrote:

the
fridge, radar, and autopilot must be turned off if the engine is
running and the batteries are not fully charged?

Of course not. It is important however to get the batteries back up
to at least the 80 or 90% level in a reasonable length of time. If
the alternator belts are slipping/burning at less than the 100 amp
level, something is wrong, probably belt tension or belt type. Over
100 amps dual belts are generally necessary.

* Wayne.B wrote, On 8/11/2007 12:08 AM:
On Fri, 10 Aug 2007 18:29:15 -0400, Jeff wrote:

the
fridge, radar, and autopilot must be turned off if the engine is
running and the batteries are not fully charged?

Of course not. It is important however to get the batteries back up
to at least the 80 or 90% level in a reasonable length of time.

But you can run a lot of stuff tapping power off a 100 Amp alternator
and still leave it with a lot of charging power. In my case, the 30
Amp fridge, the TV, computer, and all the instruments don't come up to
50 Amps. My point with the fridge is that it going to use the power
at some time during the day, its more efficient to do it directly off
the charge source.

If
the alternator belts are slipping/burning at less than the 100 amp
level, something is wrong, probably belt tension or belt type. Over
100 amps dual belts are generally necessary.

Alignment is a common cause - being off 1/8 inch will kill a belt in
no time. Also, a faulty regulator that's "spiking" the field voltage
can do it.

"Jeff" wrote in message ...
Oddly, you're always claiming that charging a 450 Ah bank at 80 or 90 Amps
is doing great damage. What I'm doing is reduces that to 50 Amps
charging, with 30 Amps to the fridge. Are you claiming that the fridge,
radar, and autopilot must be turned off if the engine is running and the
batteries are not fully charged?

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you know
the difference, but it does make things confusing. For example, my refrig
draws about 5A when running, which it does perhaps 6 hours a day in the
tropics. This gives a 24-hour consumption of 30 Ah (at 12V).

-Paul
-S/V VALIS

On Sat, 11 Aug 2007 09:47:02 -0700, "Paul" wrote:

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you know
the difference, but it does make things confusing. For example, my refrig
draws about 5A when running, which it does perhaps 6 hours a day in the
tropics. This gives a 24-hour consumption of 30 Ah (at 12V).

That sounds incredibly efficient. What size box do you have and what
kind of system? Holding plates? Compressor type?

"Wayne.B" wrote in message
...
On Sat, 11 Aug 2007 09:47:02 -0700, "Paul" wrote:

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you know
the difference, but it does make things confusing. For example, my refrig
draws about 5A when running, which it does perhaps 6 hours a day in the
tropics. This gives a 24-hour consumption of 30 Ah (at 12V).

That sounds incredibly efficient. What size box do you have and what
kind of system? Holding plates? Compressor type?

I have a Seafrost BD12 compressor/cold-plate (air) system, and the box is
perhaps 6 cu ft (I am trying to picture it, and this is merely an estimate).
It is reasonably well-insulated, but not spectacularly so. I usually put a
foam insulation sheet on top of the counter/lid to reduce the thermal loss.
I have measured the current drain, and it is indeed 5A. I have not
carefully measured the cooling duty-cycle, so I may be off a bit on the
daily AH. I don't think that it runs more than 1/3 of the time, though (8Hr
per day * 5A = 40AH) -- the compressor is in a locker in the aft cabin,
where I sleep, so I do know when it is running. It isn't a freezer, but it
can make ice cubes, and will keep a small amount of stuff frozen for a
while. The boat is a Pacific Seacraft 44.

Let's just say I put out these numbers as an example of AH calculations, not
necessarily an accurate measurement of my system's power consumption.

-Paul
-S/V VALIS
..

* Paul wrote, On 8/11/2007 12:47 PM:
"Jeff" wrote in message ...
Oddly, you're always claiming that charging a 450 Ah bank at 80 or 90 Amps
is doing great damage. What I'm doing is reduces that to 50 Amps
charging, with 30 Amps to the fridge. Are you claiming that the fridge,
radar, and autopilot must be turned off if the engine is running and the
batteries are not fully charged?

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you know
the difference, but it does make things confusing. For example, my refrig
draws about 5A when running, which it does perhaps 6 hours a day in the
tropics. This gives a 24-hour consumption of 30 Ah (at 12V).


Nope - I meant what I said. My system has "open components" where the
compressor is belt driven by a 1/2 HP motor, rating at 39 Amps DC.
For the "noon to noon" day just finished, I had two runs (evening and
morning) of about half an hour for the fridge and freezer together
drawing 30 Amps, so they were 15 Amp-hours each. These pull down
three holding plates, one in the fridge and two in the freezer. This
morning I forced the freezer to run by itself (there's a solenoid on
the coolant line to the fridge) for and extra 30 minutes at 20 Amps.
The total for the day was 41 Amp-hours.

The reason for forcing the freezer is twofold - first, the thermostat
sometimes sticks "on" so if I'm one board monitoring I just turn it
off and add some time as needed. The other reason was to force it to
run while I was running my small genset.

In warmer climates the runs would be longer (because the cooling water
is warmer) and there might be a third run because of increased heat
loss. The worst case is sitting unattended at the dock because the
boat heats up so much.

Your system seems very efficient. I'm guessing its a BD50 based
system with a small, well insulated box, and good air flow over the
condenser.

"Jeff" wrote in message
...
* Paul wrote, On 8/11/2007 12:47 PM:
"Jeff" wrote in message
...
Oddly, you're always claiming that charging a 450 Ah bank at 80 or
90 Amps is doing great damage. What I'm doing is reduces that to 50
Amps charging, with 30 Amps to the fridge. Are you claiming that
the fridge, radar, and autopilot must be turned off if the engine is
running and the batteries are not fully charged?

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you
know the difference, but it does make things confusing. For example,
my refrig draws about 5A when running, which it does perhaps 6 hours
a day in the tropics. This gives a 24-hour consumption of 30 Ah (at
12V).


Nope - I meant what I said. My system has "open components" where the
compressor is belt driven by a 1/2 HP motor, rating at 39 Amps DC. For
the "noon to noon" day just finished, I had two runs (evening and
morning) of about half an hour for the fridge and freezer together
drawing 30 Amps, so they were 15 Amp-hours each. These pull down
three holding plates, one in the fridge and two in the freezer. This
morning I forced the freezer to run by itself (there's a solenoid on
the coolant line to the fridge) for and extra 30 minutes at 20 Amps.
The total for the day was 41 Amp-hours.

The reason for forcing the freezer is twofold - first, the thermostat
sometimes sticks "on" so if I'm one board monitoring I just turn it
off and add some time as needed. The other reason was to force it to
run while I was running my small genset.

In warmer climates the runs would be longer (because the cooling water
is warmer) and there might be a third run because of increased heat
loss. The worst case is sitting unattended at the dock because the
boat heats up so much.

Your system seems very efficient. I'm guessing its a BD50 based
system with a small, well insulated box, and good air flow over the
condenser.


The cooling water is warmer? Therein lies the key to you efficiency. I
bet you don't count the amps the circulation pump uses? Some of those
things use up to five amps.

Wilbur Hubbard

On Fri, 10 Aug 2007 16:57:58 -0000, Skip Gundlach
wrote:

on each anchorage or dockage. Of course, like nearly any other
sailboat, we
have exhaust grime on our stern and immediately in the area of the
outlet
(which is under water due to our ever rising water line!). We enjoyed

One thing I always do when I start the engine is to make sure water is
spitting out the exhaust. If your exhaust outlet is under water, you
can't do that. Also, like any thruhull that's under water, you should
have a shutoff valve for it. But I don't think you can (or should)
put one on an exhaust outlet. So that leaves maybe moving it higher
up. Something you might have thought about when the boat was being
repaired but you can still do.

Steve

On Aug 10, 6:31 pm, Steve wrote:
On Fri, 10 Aug 2007 16:57:58 -0000, Skip Gundlach

wrote:
on each anchorage or dockage. Of course, like nearly any other
sailboat, we
have exhaust grime on our stern and immediately in the area of the
outlet
(which is under water due to our ever rising water line!). We enjoyed

One thing I always do when I start the engine is to make sure water is
spitting out the exhaust. If your exhaust outlet is under water, you
can't do that. Also, like any thruhull that's under water, you should
have a shutoff valve for it. But I don't think you can (or should)
put one on an exhaust outlet. So that leaves maybe moving it higher
up. Something you might have thought about when the boat was being
repaired but you can still do.

Steve

Hi, Steve,

We look at our filter for water movement. If it's coming in, it's
going out. More reliable than trying to stick our heads out to see
whether there was a splash, in any event, and much quicker as it's
right next to where the key is...

We thought about relocating the exhaust, but got talked out of it for
a variety of reasons. On our next extended haul we'll revisit doing
it out the transom rather than low on the stern side as it is now...

Wilbur, I don't know his system, but another's I know of uses a direct
drive 1HP motor to chill cold plates. Very high amps, relatively short
time. My estimated (see my upcoming electrical budget and scenaios)
use is over an entire day, but is more like 35-40AH.and uses, when
running full blast, as approximately yours does, 4.7A..

L8R

Skip

"Skip Gundlach" wrote in message
ups.com...
We look at our filter for water movement. If it's coming in, it's
going out. More reliable than trying to stick our heads out to see
whether there was a splash, in any event, and much quicker as it's
right next to where the key is...

We thought about relocating the exhaust, but got talked out of it for
a variety of reasons. On our next extended haul we'll revisit doing
it out the transom rather than low on the stern side as it is now...

Wilbur, I don't know his system, but another's I know of uses a direct
drive 1HP motor to chill cold plates. Very high amps, relatively short
time. My estimated (see my upcoming electrical budget and scenaios)
use is over an entire day, but is more like 35-40AH.and uses, when
running full blast, as approximately yours does, 4.7A..

L8R

Skip


Skip, it could also be coming in and going into your bilge. Also, having the
exhaust under water makes it more likely for water to back up into your
exhaust system in following seas. Free and clear of the water is for sure
the better way to go.