Download Sailplane Batteries

Sailplane Batteries
• A wide range of battery types, sizes, ratings
etc in use in the glider fleet - including Motor
Gliders.
• Motor Gliders have the extra requirement of
“starting” and extending /retracting the engine.
• Touring Motor Gliders have the advantage of
charging / maintaining the battery while the
engine is running.
• Battery type/style/model etc appears to be a
function of individual or Club preference.
• Battery technology is rapidly changing – size,
type, capacity, weight, etc.
Sailplane Batteries
• As battery technology improves, the power
requirements of individual devices - radio,
transponder, instrumentation, etc has been/ is
being progressively reduced.
• As battery users, we continue to seek a
battery that is in-exhaustable, quick to
recharge, is small and lightweight, cheap,
clean, very portable and safe – and will last
forever.
• Battery specific “terminology” is evolving.
Sailplane Batteries
Terminology
• Primary Battery
• Secondary Battery
• Specific Energy
• Spedific Power
• Cycle Life
• SLA
= Non-rechargeable.
= Re-chargeable.
= Capacity
= Power delivery (Whr/Kg)
= Number recharge cycles.
= Sealed Lead Acid
Sailplane Batteries
Battery Types
• Flooded Lead-acid. Mainly stationary, Auto’s
• Sealed Lead-acid Sailplanes, Alarm systems
• Absorbed Glass Mat
• Nickel based (NiMhi)
• Lithium based (LiFe)
– Lithium Ion
Sailplane Batteries
Battery Manufacture – Many Factors
• Specific Energy
• Size, shape, operating environment
• Service life, Recharge cycles
• Manufacturing cost / Purchasing cost
• Shelf life
• Load capability
• Safety
• Durability and Price.
Sailplane Batteries
Battery Safety
• Batteries offer significant potential for danger
to a glider pilot – battery is generally located
where it can’t be seen or got at in flight.
• Significant energy stored in a small area.
• Problems include short-circuit, overload, etc
caused by damaged circuitry.
• Missile if not adequately secured.
• Protection desired at the battery terminal –
(which may not be sufficient if battery is ill).
Sailplane Batteries
• Battery charging requires particular attention
to ensure safety and maximum battery
capacity - even to recharge a simple SLA
battery.
• Be wary when working near batteries or
battery terminals – watches, rings, spanners.
• Lithium Ion battery recharging – be wary.
– Use only the recommended charger, follow the
manufacturer’s advice.
• GFA AN on Lithium Ion batteries.
Sailplane Batteries
Battery Maintenance
• Little “routine” maintenance required other
than regular charging.
• Keep battery terminals clean, tight and well
insulated.
• A single battery charger is unlikely to satisfy
the various charging requirements of all
batteries.
• Some “intelligent” chargers now available.
Sailplane Batteries
To disconnect a battery from the system;
• Disconnect –ve lead first.
– More difficult to cause a short-circuit.
Sailplane Batteries
Charging Issues include;
– Voltage, too high / low
– Current, too high / low
– “Float” current, too high /low.
– Incorrect charge program.
– Storage – state of charge.
• Best advice – refer to the battery
manufacturer’s recommendations.
• This is particularly so with Lithium Ion
batteries.
Sailplane Batteries
Not Specific to Motor Gliders
• Battery / Electrical Circuit Protection Systems.
• Battery Security
• Battery Disposal
• CASA Notes on Lithium Ion Batteries – copy in
Basic Motor Glider Engineering..
Sailplane Batteries
Some Battery / Electrical Issues
• Not adequately secured.
• Inadequate electrical protection;
– Electrical protection – rating, insulation.
– Inadequate battery security.
– End of useful life – runs flat quickly.
– Inadequate wiring (rating, security, protection).
– Inappropriate (no) protection / isolation systems.
• Cheap copies of “modern” batteries, without
inbuilt safety & protection systems.
Sailplane Batteries
Sailplane Batteries