Photovoltaic (PV) solar panels are now an accepted part of a cruising boat's electrical power inventory, and rightly so since they produce consistent power year after year with no noise, smell, or moving parts. They are especially popular on multihulls and boats with wider beams, where panel mounting options are numerous.
HOW THEY WORK
- PV panels convert light energy directly into electricity through the use of thin, specially treated silicon cells.
- When exposed to sunlight, each cell in a panel produces about 0.5 volts, regardless of cell size.
- Roughly 36 cells are connected in series to create sufficient voltage (17-19 volts) to charge a 12-volt battery even when light levels are low.
- Amount of current relates to cell size as well as to how much light is reaching the cells.
RATING
- PV panels are rated according to their "peak" output in amps and watts (i.e. their best performance in favorable conditions).
- Shading, clouds, and facing away from the sun all contribute to power loss.
- Multiple PV panels can be wired in parallel according to desired current output, available mounting space and budget.
TYPES
Standard PV panels
- The covers are sturdy tempered glass with aluminum perimeter frames for rigidity.
- Long warranties are provided against power loss for up to 25 years.
- Standard panels are most cost efficient in terms of dollars per watt.
- These panels cannot be walked on, are heavier than marine panels, and don't have as many mounting options as marine panels.
Marine PV panels
- The covers are made of polymers with no perimeter frames.
- Marine panels are lightweight, can be walked on, and can be mounted in a variety of ways. Some models are fully flexible for mounting on biminis and dodgers.
Both are completely weatherproof and able to withstand tough conditions at sea.
NEW TECHNOLOGY
Despite laboratory breakthroughs using exotic materials, the efficiency of commercially available panels has improved only marginally in the last decade, proof that this technology has arrived.
The main PV solar panel advances in recent years are:
- Fully flexible panels that use thin film cell technology.
- Blocking diodes between cells that prevent total power loss when part of the panel is shaded.
- Lower panel cost per watt.
- More creative mounting methods.
ACCESSORIES
- Charge controllers, to prevent battery overcharge, and an output monitor panel.
- PV solar panels work well on their own for small electrical loads, or combined with wind and water generators or engine-driven power sources for larger loads.
INSTALLATION
Permanent installations depend on the panel type. All will require an electrical toolbox and electrical knowledge.
Standard type (Rigid frame panels)
Toolbox
- Mounting brackets if a permanent installation is desired
- Drill and bits
- Bolts, nuts, and washers
- Screwdriver
- Tin-plated wire
- Connectors
- Wire stripper/cutters
- Wire ties and clips
- Regulator or in-line fuse protection
- Multi-meter
- Soldering iron, if soldering is required
Marine type (Flexible panels)
Toolbox
- Mounting brackets if a permanent installation is desired
- Drill and bits
- Bolts, nuts, and washers
- Screwdriver
- Small diameter line for removable installations
- Tin-plated wire
- Connectors
- Wire stripper/cutters
- Wire ties and clips
- Regulator or in-line fuse protection
- Multi-meter
- Soldering iron, if soldering is required
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