Re: [Electric Boats] Marine Solar Array makes 3 knots

 

Power developed by tracking can be at least twice the horizontal installation power output. When designing a solar house in a high sunshine environment it is claimed the panels will give about 6 hours worth of the rated capacity of the panels in day - that is positioning the panels on a roof at an angle appropriate for the latitude. When I tested a bank of solar panels just before sunset by aiming them at the sun (only a few degrees above the horizon) the panels gave close to the full rated current. So if you had a tracker that keeps the panels facing the sun for close to 12 hours a day, then that would already double the panels' output compared to the 6 hours worth in a solar house array.

 

Once you talk about boat installations you generally mount the panels horizontally, so whatever latitude you are at, you lose any advantage you would gain by tilting them to compensate for the latitude (like you would on house), plus you also end up with various shadows falling across the panels during the course of a day in most boat installations. So there is a lot of room for optimisation there.  10x  worth?  I don't know about that, but possibly if you compare the output of a tracked system with a badly installed panel on a sailing boat with lots of stay wires, a mast or two and a wind generator mast that is also often mounted right next to the solar panels on the back davits. Then you might be able to achieve 10 times the output by having a free tracking system that gets rid of all the obstacles.

 

 

----- Original Message -----

From: Myles Twete

To: electricboats@yahoogroups.com

Sent: Monday, October 03, 2011 7:14 AM

Subject: RE: [Electric Boats] Marine Solar Array makes 3 knots

 

James noted:

"Tracker Expected to be released soon.  By Focusing on the sun, power developed is as high as 10 times more than if panels are mounted horizontally"

Really…10x?

Would you believe 18%: http://www.civicsolar.com/resource/effect-array-tilt-angle-energy-output

Array Tilt Angle (degrees)	Phoenix, AZ (33 North)		Portland, OR (45 North)
	Annual Production (kWh)	Delta (%)	Annual Production (kWh)	Delta (%)
0 - flat	5,723	0	3,624	0
10	6,178	+8%	4,019	+9%
20	6,461	+13%	4,239	+15%
30	6,575	+15%	4,355	+18%
40	6,526	+14%	4,368	+18%
50	6,310	+10%	4,279	+16%
90 - vertical	3,966	-31%	2,967	-20%

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of James
Sent: Sunday, October 02, 2011 6:37 PM
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Marine Solar Array makes 3 knots

 

We have just recently completed testing of our solar array which you can find on the website at

http://www.propulsionmarine.com/electric/charging-sources

SOLAR - The Propulsion Marine Solar Array Features:

2 x 225 watt Sanyo Panels for total of 450 watts at 90 Volts

Midnite Solar Charge Controller

Electric Actuator Lift Arm

Electric Worm Gear Chain Drive to Rotate Pole

Joystick Control

Tracker Expected to be released soon.

By Focusing on the sun, power developed is as high as 10 times more than if panels are mounted horizontally

Kapowai is capable of obtaining 3 knots while motoring under power made directly from the solar panel.

James

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