Solar power for RC: a step-by-step endurance build log

Solar power for RC: a step-by-step endurance build log

I started this project to extend the endurance of a ready-to-fly foam glider for long-range reconnaissance practice, with a focus on practical solar cells, MPPT integration and real-world flight behaviour testing.

The first phase was parts selection and layout so I listed the components I expected to need and prioritised low weight and proven reliability for each item.

• Lightweight monocrystalline solar cells (2–4 small panels to fit the wing camber).
• A small MPPT charger capable of handling 10–20 watts and LiPo charging profiles.
• A 2S or 3S LiPo with a dedicated balance lead and a low internal resistance for discharge.
• Thin silicone-insulated wire, low-profile connectors and heat-shrink for joints.
• A lightweight voltage and current telemetry sensor for in-flight logging.
• Structural adhesive, Kapton tape and a simple 3D printed bracket for the MPPT module.

Choosing solar cells was a balance between efficiency, weight and form factor, and I settled on small monocrystalline cells because they give the best watt-per-gram for this scale of build and conform well to a slightly curved wing surface.

Mounting the cells took a couple of iterations, starting with a test rig glued to a foam piece to check adhesion and flex before committing to the real wing, and I used thin strips of EVA foam under the cells to prevent hard spots while bonding with a flexible silicone adhesive.

For the MPPT I opted for a compact module with a wide input range and a LiPo charge profile because it improves solar harvesting under variable sun and reduces lost energy compared with a raw regulator, and I mounted the MPPT in a 3D printed bracket in the fuselage bay to keep wiring short and accessible.

Wiring and safety were key; I soldered cells in series to reach the MPPT input while keeping current manageable, used a small fuse on the battery line, fitted a proper balance connector and integrated a telemetry shunt so I could monitor both panel current and battery voltage in flight and on the ground.

Once assembled, I flew a schedule of tests to build an energy budget by recording solar input, average cruise current and worst-case sink when climbing, and that data guided final decisions on whether to increase panel area, upgrade the MPPT or choose a higher-capacity pack for longer-range sorties.

During long-range trials I learned to angle the aircraft for optimal sun incidence during climbs to top-up the batteries and to programme the autopilot to choose glide paths that conserve energy, and I keep full build notes and downloadable diagrams on my site at https://watdafeck.uk to help other hobbyists replicate the setup.

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