Well, back from the boat for a bit, and trying to keep up...

"Larry W4CSC" wrote in message
...
"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!

Well, that's sorta what I thought.

First, these (whatever they turn out to be, based solely on first, space,
and second, availability) will be run through an MPPT which will allow me
higher voltage/smaller wires - for example, ones designed for 24V systems..
Second, it appears I'll not be able to get the 500W I wanted - but quite
possibly more than 450, e.g 3x http://www.partsonsale.com/bp4170.pdf 170w
63x31, 34v or 4x http://www.affordable-solar.com/kc125g125watt.html 125w
56x26 24v but Third, these are going on our arch
http://www.justpickone.org/skip/gall...rch&star t=42
which, on construction, appears not to have the space above I'd expected.
So, back to the drawing boards for what will fit up there. You can muck
around in the rest of that gallery to see what else we'd looked at in coming
up with the specs and drawings. In any event, moving about on deck won't be
an issue..

None the less, 400W isn't out of the realm of possibility. Real world
experience suggests "normal" accumulation of something above 125AH/day...

The arch is in the rough welded stage, without any of the custom hang-ons,
at the moment. I assume it will be finished by my next time down there,
which I expect to be 10 days or so, when I'll take up the regimen of staying
on the boat for 3 weeks and coming home for one, in hopes of finishing in
May, as I have another surgery scheduled for June 6th, this time to relocate
muscle from my back to replace the dead ones in the rotator cuff...

L8R

Skip and Lydia, refitting as fast as we can


--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"There is nothing-absolutely nothing-half so much worth doing as simply
messing about in boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter, that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do, and
you can do it if you like, but you'd much better not."

Im not sure the MPPT controller allows for higher voltage/smaller wires. PV arrays are to some
extent constant current and a "12 volt" array will put out its maximum power at a voltage
typically higher than the battery. So if you hook the array up to a battery with a "cheap"
controller, it is basically a direct connection and the PV current stays about the same but the PV
array voltage drops to the battery voltage so you can lose a fair amount of delivered power. The
MPPT controller allows the array voltage to operate for maxiimun power while supplying current to
the battery at the batteries charge current. I have a 160 watt pannel (2x80w Kyocera) and
typically I might have 8 amps comming out of the panel and maybe 10.5 going into the battery (the
currents will of course vary all over depending on how much sunlight, angle, ect).

Also, the MPPT charger I have (Blue Sky - company used to be called RV) is intelegent about
properly charging the batteries which can make them last longer. Ive only had this product for
several months but think it was a good investment.

wh

Skip Gundlach wrote:

Well, back from the boat for a bit, and trying to keep up...

"Larry W4CSC" wrote in message
...
"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!

Well, that's sorta what I thought.

First, these (whatever they turn out to be, based solely on first, space,
and second, availability) will be run through an MPPT which will allow me
higher voltage/smaller wires - for example, ones designed for 24V systems..
Second, it appears I'll not be able to get the 500W I wanted - but quite
possibly more than 450, e.g 3x http://www.partsonsale.com/bp4170.pdf 170w
63x31, 34v or 4x http://www.affordable-solar.com/kc125g125watt.html 125w
56x26 24v but Third, these are going on our arch
http://www.justpickone.org/skip/gall...rch&star t=42
which, on construction, appears not to have the space above I'd expected.
So, back to the drawing boards for what will fit up there. You can muck
around in the rest of that gallery to see what else we'd looked at in coming
up with the specs and drawings. In any event, moving about on deck won't be
an issue..

None the less, 400W isn't out of the realm of possibility. Real world
experience suggests "normal" accumulation of something above 125AH/day...

The arch is in the rough welded stage, without any of the custom hang-ons,
at the moment. I assume it will be finished by my next time down there,
which I expect to be 10 days or so, when I'll take up the regimen of staying
on the boat for 3 weeks and coming home for one, in hopes of finishing in
May, as I have another surgery scheduled for June 6th, this time to relocate
muscle from my back to replace the dead ones in the rotator cuff...

L8R

Skip and Lydia, refitting as fast as we can

--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"There is nothing-absolutely nothing-half so much worth doing as simply
messing about in boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter, that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do, and
you can do it if you like, but you'd much better not."

Where did the extra 2.5 amps come from?

Roger

http://home.earthlink.net/~derbyrm

"Walt" wrote in message ...
snip
... I have a 160 watt pannel (2x80w Kyocera) and
typically I might have 8 amps coming out of the panel and maybe 10.5 going
into the battery (the
currents will of course vary all over depending on how much sunlight,
angle, ect).

The MPPT controller allows the PV array to operate at its maximum power point
which for example might be 8 amps at 16.4 volts. So the power output is 8*16.4 =
131 watts. The MPPT controller using some sort of power switching topology
transfers almost all of the power to the battery which is for example at 12.5
volts. The current at 131 watts and 12.5 volts is 10.5 amps. So its 8 amp in at
16.4 volts and 10.5 amps out at 12.5 volts - ie,. the power is maintained. If
you simply had connected the PV array to the battery (which is essentially what
most controllers do), the current output of the PV array would have remianed
constant but the voltage would have dropped to the battery voltage so the power
delivered would have been approx 8amps * 12.5 volts = 100 watts - ie,
significantly less than with the MPPT controller.

The one I have draws about 100 ma so it doesnt "break even" until its running
about .5 amps to the battery. MPPT contollers are also a fair amount more
expensive so must compete with simply adding more solar panel area. However, if
you want to keep the PV area as small as possible (like on a boat), it seems
like a good product.

Roger Derby wrote:

Where did the extra 2.5 amps come from?

Roger

http://home.earthlink.net/~derbyrm

"Walt" wrote in message ...
snip
... I have a 160 watt pannel (2x80w Kyocera) and
typically I might have 8 amps coming out of the panel and maybe 10.5 going
into the battery (the
currents will of course vary all over depending on how much sunlight,
angle, ect).

That's a lot more sophisticated that I expected from a "controller!" Can it
charge the batteries even if the solar cell voltage drops below the battery
voltage?

Do they have the "secondary" considerations such as RFI and waterproofing
dealt with as well?

Roger

http://home.earthlink.net/~derbyrm

"Walt" wrote in message ...
The MPPT controller allows the PV array to operate at its maximum power
point
which for example might be 8 amps at 16.4 volts. So the power output is
8*16.4 =
131 watts. The MPPT controller using some sort of power switching topology
transfers almost all of the power to the battery which is for example at
12.5
volts. The current at 131 watts and 12.5 volts is 10.5 amps. So its 8 amp
in at
16.4 volts and 10.5 amps out at 12.5 volts - ie,. the power is maintained.
If
you simply had connected the PV array to the battery (which is essentially
what
most controllers do), the current output of the PV array would have
remianed
constant but the voltage would have dropped to the battery voltage so the
power
delivered would have been approx 8amps * 12.5 volts = 100 watts - ie,
significantly less than with the MPPT controller.

The one I have draws about 100 ma so it doesnt "break even" until its
running
about .5 amps to the battery. MPPT contollers are also a fair amount more
expensive so must compete with simply adding more solar panel area.
However, if
you want to keep the PV area as small as possible (like on a boat), it
seems
like a good product.

Roger Derby wrote:

Where did the extra 2.5 amps come from?

Roger

http://home.earthlink.net/~derbyrm

"Walt" wrote in message
...
snip
... I have a 160 watt pannel (2x80w Kyocera) and
typically I might have 8 amps coming out of the panel and maybe 10.5
going
into the battery (the
currents will of course vary all over depending on how much sunlight,
angle, ect).

"Walt" wrote in message ...
Im not sure the MPPT controller allows for higher voltage/smaller wires.
PV arrays are to some
extent constant current and a "12 volt" array will put out its maximum
power at a voltage
typically higher than the battery. So if you hook the array up to a
battery with a "cheap"
controller, it is basically a direct connection and the PV current stays
about the same but the PV
array voltage drops to the battery voltage so you can lose a fair amount
of delivered power. The
MPPT controller allows the array voltage to operate for maxiimun power
while supplying current to
the battery at the batteries charge current. I have a 160 watt pannel
(2x80w Kyocera) and
typically I might have 8 amps comming out of the panel and maybe 10.5
going into the battery (the
currents will of course vary all over depending on how much sunlight,
angle, ect).

Also, the MPPT charger I have (Blue Sky - company used to be called RV) is
intelegent about
properly charging the batteries which can make them last longer. Ive only
had this product for
several months but think it was a good investment.

wh

Blue sky was the make my installer (svhorizon.com, KISS US distributor)
recommended. It was his suggestion that I go to the higher voltage panels in
order to make for smaller wires possible with the same voltage drop (thus
the need for MPPT). As much wattage as we'll have, and as far as it has to
run to the ER, after the trip down the (tall) arch, drop is of concern.

Unfortunately, they're driving to the Oakland show and won't be available to
start on the project for nearly a month. Then, I hope to get the electrical
stuff buttoned up quickly, as I have what is now a very short window to get
the boat finished before my surgery.

L8R

Skip


--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain