Specifications

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Figure 5.10.1. Solar panel array with cells linked in series (A, left) or in matrix (B, right).
During even reasonably short deployments, surface floating buoys such as the Waverider
cannot avoid suffering from marine growth, salt crystals, bird deposits and physical knocks.
Shadows cast by the antennae and fixings will also intrude between the sun and the solar cells.
Therefore, a novel cell configuration has been used to deal with these situations.
Usually a solar panel array consists of many small solar cells connected in series. When a
shadow blocks light to an individual cell or a cell is damaged, the chain is broken and the whole
section stops producing energy (see Fig 5.10.1A). The solar panel array on the Waverider
overcomes this potential problem by linking the solar cells in a matrix (see Fig 5.10.1B). When
any one cell is blocked, current can still flow through the neighbouring cells in the matrix. In the
unlikely case that a complete row in the matrix is blocked, no more current would flow but the
probability of this happening is minimised by placing the individual cells of a row as remote as
possible from each other.
5.10.3.2 Boostcap capacitors
The pivotal innovative feature of the hybrid Waverider is the Boostcap capacitor. An array of
these specialised, ultra high capacity capacitors is used to store surplus solar energy during the
day. A normal power supply capacitor typically has a capacity of 0.0047F (Farad = unit in
which capacity is expressed). Boostcaps are available in capacities up to 2600F (2.5 Volt). That
is half a million times more than a normal power supply capacitor. Although Boostcaps do not
come anywhere near the storage capacity of lead-acid batteries, the extremely efficient, low
power consumption electronic design of the Waverider ensures that enough energy can be
stored to power the Waverider through the night. The main operational advantage of the
Boostcap is its robustness - it is a completely maintenance-free component and can be charged
and discharged millions of times. This makes the Boostcap ideally suitable for applications at
sea.
The power storage pack consists of 24 Boostcap capacitors 2.5 Volt 350 F. Each cell is
limited to 2.2 Volt. The capacitors are mounted with two in parallel on a printed circuit board.
12 of these united in series make a power storage pack of 58 F and 28 Volt. For safety a 10 A
fuse is incorporated in the wiring of the power storage pack.
5.10.3.3 Operation
Though the solar panel generate sufficient energy to power the buoy, the electronics does not
start up without power of the primary cells, or on the external power supply connector(s) on the
electronics unit.
The block of Boostcap capacitors are equipped with charging electronics. In order to
prevent overloading of these capacitors, the excess energy is dissipated in the block. In order to
prevent excess temperature built up in the power storage pack when dissipating excess energy,
the current should be limited to 200 mA when charging the Boostcaps with an external power
supply.
Marine growth on the solar panel can be removed by means of a regular pressure washer.
This will not damage the panel neither by scratching the polycarbonate, nor by affecting the lute
between the panel and the stainless steel.
In case the solar panel do gets scratched, it can be removed. Contact Datawell.