On Sun, 20 Mar 2005 21:23:15 -0500, Larry W4CSC
wrote:

"Skip Gundlach" skipgundlach sez use my name at earthlink dot
fishcatcher (net) - with apologies for the spamtrap wrote in
:

Hm. Help me with the math. As a lapsed math, physics and chem major,
I don't remember my stuff all that well. However, I'll have right in
the neighborhood of 500W solar

How big are these solar panels? A Kyocera KC120 panel at 120 watts is:
Max power: 120 Watts
Max voltage: 16.9 Volts
Max current: 7.10 Amps
Dimensions (LxWxD): 56.1" x 25.7" x 2.2"
Weight: 26.3 lbs

4 of those kinda hinders going on deck, I suppose. Or, do you mean 500
watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice!

, and a KISS wind generator in the
Caribbean. Various vendors suggest I take the wattage and divide by 3,
or 4 if really lousy weather, for a reasonable typical AH input,
daily. My math has that at 170-125AH/day, plus some other unknown -
but apparently pretty substantial - AH from a KISS.

Solar is useless on cloudy days, but that's when the wind is usually
blowing so you got it covered.

Speaking of wind power, have you see http://www.otherpower.com/
These homebrewers are really producing KWh!


Our anticipated daily budget is about 125AH; we'll have (for
simplicity in this calculation) ~1250AH capacity. It's our
presumption that we'll have 4-5 days capacity, in the most
unimaginable (in the Caribbean) circumstance of continuous no wind or
sun.

Have I missed something here?

No, not at all. The big inverters are great for QUICK and TEMPORARY loads,
even heavy loads if the battery banks can produce the heavy load currents
without sagging a lot.

Too bad boats don't use 48 volts instead of "car power". The whole thing
becomes much more efficient as the voltage rises.

Design development is under way for 42 volt car systems

Brian W

"Brian Whatcott" wrote in message
...
Design development is under way for 42 volt car systems

It's already there. AFAIK all new VW marine diesels have a 42V system to
power the injectors.

Meindert

"Meindert Sprang" wrote in
:

It's already there. AFAIK all new VW marine diesels have a 42V system to
power the injectors.

Meindert




I think the Toyota Prius hybrid takes this even further with a 480VDC
system, doesn't it? A friend has one and it's quite impressive, once you
get used to NOT starting the engine to take off from the parking lot.
That's a bit unnerving, just turning it on and driving away...(c;

"Wayne.B" wrote in message
...
On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara"
wrote:

The long winded point is that a 900AH Battery and an inverter will not run
a
Heater all weekend.

=================================

That's true but it will run a heater for 7 or 8 hours at night which
is all you really need (assuming you can recharge in the morning).

Nope. Our Pelonus ceramic cube heater draws around 110A. With a
900AH battery bank you would be lucky to get 4 hours. Probably
less since it is drawing much more than the 20 hour rate from which
your 900AH rating is based. We have a 500AH+ bank in our mobile
canvas shop. The heater is good for about an hour.

Doug

Hi Doug

You mean 110 Volts not amps don't you? About 13.5 amps.
JR;


Doug Dotson wrote:
"Wayne.B" wrote in message
...

On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara"
wrote:


The long winded point is that a 900AH Battery and an inverter will not run
a
Heater all weekend.

=================================

That's true but it will run a heater for 7 or 8 hours at night which
is all you really need (assuming you can recharge in the morning).


Nope. Our Pelonus ceramic cube heater draws around 110A. With a
900AH battery bank you would be lucky to get 4 hours. Probably
less since it is drawing much more than the 20 hour rate from which
your 900AH rating is based. We have a 500AH+ bank in our mobile
canvas shop. The heater is good for about an hour.

Doug

You are right. Sorry about that. I should have read the whole thing.
JR

JR Gilbreath wrote:

Hi Doug

You mean 110 Volts not amps don't you? About 13.5 amps.
JR;


Doug Dotson wrote:

"Wayne.B" wrote in message
...

On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara"
wrote:


The long winded point is that a 900AH Battery and an inverter will
not run a
Heater all weekend.


=================================

That's true but it will run a heater for 7 or 8 hours at night which
is all you really need (assuming you can recharge in the morning).



Nope. Our Pelonus ceramic cube heater draws around 110A. With a
900AH battery bank you would be lucky to get 4 hours. Probably
less since it is drawing much more than the 20 hour rate from which
your 900AH rating is based. We have a 500AH+ bank in our mobile
canvas shop. The heater is good for about an hour.

Doug

On Mon, 21 Mar 2005 17:09:48 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

Nope. Our Pelonus ceramic cube heater draws around 110A. With a
900AH battery bank you would be lucky to get 4 hours. Probably
less since it is drawing much more than the 20 hour rate from which
your 900AH rating is based. We have a 500AH+ bank in our mobile
canvas shop. The heater is good for about an hour.

=============================================

That assumes continuous duty. Unless you have a really large cabin
and/or a really cold night, the heater is actually on less than 30% of
the time. I had a 440 AH bank on my old boat and we would usually
make it through the night. I could hit the generator start button in
the morning without getting out of bed. :-)

"Wayne.B" wrote in message
...
On Mon, 21 Mar 2005 17:09:48 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

Nope. Our Pelonus ceramic cube heater draws around 110A. With a
900AH battery bank you would be lucky to get 4 hours. Probably
less since it is drawing much more than the 20 hour rate from which
your 900AH rating is based. We have a 500AH+ bank in our mobile
canvas shop. The heater is good for about an hour.

=============================================

That assumes continuous duty. Unless you have a really large cabin
and/or a really cold night, the heater is actually on less than 30% of
the time. I had a 440 AH bank on my old boat and we would usually
make it through the night. I could hit the generator start button in
the morning without getting out of bed. :-)

Depends upon alot of things, like the outside temperature, the insulation
of the boat, etc. I keep an electric heater on all winter and if the temp is
below 40, it runs alot more than 30%.

On Tue, 22 Mar 2005 20:47:30 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

Depends upon alot of things, like the outside temperature, the insulation
of the boat, etc. I keep an electric heater on all winter and if the temp is
below 40, it runs alot more than 30%.

======================================

I'm sure that's true but I'd probably be plugged into dock power in
that kind of weather.

Well whats wrong with a good electric blanket and a heavy comforter to keep
warm over night. That would be alot less taxing on an electrical system. You
still have to be able to recharge, but getting through the night should be
easy.

John

"Larry W4CSC" wrote in message
...
"Meindert Sprang" wrote in
:

It's already there. AFAIK all new VW marine diesels have a 42V system to
power the injectors.

Meindert




I think the Toyota Prius hybrid takes this even further with a 480VDC
system, doesn't it? A friend has one and it's quite impressive, once you
get used to NOT starting the engine to take off from the parking lot.
That's a bit unnerving, just turning it on and driving away...(c;