Radios and other electronic devices must be battery-powered. What sort of battery - and does its capacity impose a limit on flight duration, or can they be recharged in flight with a turbine?


Gliders generally use "Gel Cell" or Sealed Lead Acid rechargeable batteries, a little bigger than a block of butter, that will run designed-for-glider low wattage radios, and sometimes transponders, and FLARM systems (a kind of TCAS) and various other gadgets, and are good for several hours of operation (the total current draw of all the services might be under 1A when not transmitting on the radio, so a 5 AmpH Gel Cell 12v battery might be plenty unless you are talking all the time). Enough for normal glider flights and tasks, and if necessary you can hook up a second one if expect to be out for more than 4-5 hours.

Some newer batteries of the more exotic Lithium chemistry are starting to come on the scene, but the thing is the gel cells are light enough and are effective and trouble free, and don't require an STC (Supplemental Type Certificate; basically a 3rd party field modification), so the switch away from gel cells will be slow.

Recharging in flight with a turbine would be a real L/D killer so it's out of the question. Much better just to install provision for a second battery for long flights.

  • $\begingroup$ Nice answer. I've also seen small solar panels on the glareshield or turtleback. They help the lead-acid battery last longer in flight and save the hassle of removing it from the aircraft to recharge between flights. $\endgroup$ – pericynthion Jun 18 '19 at 3:54
  • $\begingroup$ Thanks. Can you expand "STC"? $\endgroup$ – Daniele Procida Jun 18 '19 at 7:22
  • $\begingroup$ Block of butter can come in various sizes. Can you use a better example? $\endgroup$ – Steve Jun 20 '19 at 21:27
  • $\begingroup$ Say, roughly, 3" wide, 6" long, 5" high. Something you can hold in your hand like a brick. At least the ones in my club's gliders. $\endgroup$ – John K Jun 20 '19 at 21:35

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