Pushing the limits with lithium-ion batteries

I was travelling to Graubünden the past weekend, and I took the opportunity to test my custom-assembled Lithium-ion battery pack for use on my 5" mid-range build. Lithium-ion cells have a higher energy density than the usual Lithium-polymer batteries used in this hobby. Therefore, for a similar weight, they will provide more capacity, leading to more flight time. In early testings, I was able to fly more than 13 minutes on a single 3s2p pack (6200mAh) with 5 inch propellers, even when giving decent amounts of throttle. This is way more than anything I have achieved before on 5 inch and allows me to reach further out. In this video, I reached 3km out without breaking a sweat, and I kinda regret not going for more, since I had plenty of time to do so. Next goal is 5km! The choice of using a 3-cell battery (6 cells in total, two in parallel) was made to limit the total weight of the battery. I figured I needed 2 cells in parallel to give me enough max current (30A continuous, 60A burst). 4s2p is roughly 420g assembled, which is perfect for my 7" rig, but too heavy for my 5". So I went for 3s2p for a total of 325g. To compensate for the lack of RPM compared to 4s, I used high-kv motors, as well as propellers with a slightly bigger diameter and steep pitch (Azure 5150). I find that they give enough thrust on 3s to comfortably fly around in the mountains. A word on jello/vibrations: in the first half of the video I flew without knowing I had vibrations, just after flashing a new firmware. After reviewing the blackbox, I noticed there were some vibrations around 220Hz, applied a notch filter there and you can see the result in the second half of the video. No more jello effect! Check this guide to make your own li-ion endurance pack: https://blog.seidel-philipp.de/diy-build-a-longrange-lithium-ion-battery/ The cells I chose are these: Sony / Murata Konion US18650VTC6 3120mAh - 30A Test: https://lygte-info.dk/review/batteries2012/Sony%20US18650VTC6%203000mAh%20%28Green%29%20UK.html THE QUADS: ======== FREESTYLE - MID RANGE --------------------- Frame: Armattan Rooster 5" Flight Controller: HelioRC Spring ESCs: Hobbywing XRotor 4-in-1 40A dshot600 Motors: T-Motor F40 Pro II 2600kv Props: Azure Power 5150 FPV Cam: Runcam Swift 2 RX: TBS Crossfire Micro RX v2 vTX: FuriousFPV Stealth LR Antenna: TBS Triumph HD Camera: GoPro Hero5 Session Batteries: Custom Li-ion / Swaytronic / KDlipo GPS: RTFQ Micro Ublox M8N GPS Glonass LONG-RANGE ---------------- Frame: iFlight XL7 Flight controller: HelioRC Spring ESCs: Hobbywing XRotor 4-in-1 40A multishot Motors: T-Motor F80 2200kv Props: Master Airscrew Rs 6x4.5x3 / DAL Cyclone 6040 / Gemfan Flash 7042 FPV Cam: Runcam Eagle 2 16:9 RX: TBS Crossfire Micro RX v2 vTX: TBS Unify v3 Antenna: TBS Triumph HD Camera: GoPro Hero5 Session Batteries: Custom Li-ion / Swaytronic / mylipo.de GPS: RTFQ Micro Ublox M8N GPS Glonass RACE 1 and RACE 3 (identical) ---------------- Frame: Karearea Talon Flight controller: Hobbywing XRotor F4 AIO ESCs: Hobbywing XRotor 4-in-1 40A dshot600 Motors: XNova Lightning 2207 2600kv Props: HQProp 5x4.3x3 V1S FPV Cam: Runcam Micro Swift 2 RX: TBS Crossfire Nano vTX: FuriousFPV Stealth Race Antenna: Lumenier AXII Stubby Batteries: Swaytronic, KDlipo RACE 2 ---------------- Frame: Custom (more info soon!) Flight controller: Hobbywing XRotor F4 G2 ESCs: Hobbywing XRotor 4-in-1 G2 45A dshot1200 Motors: XNova Lightning 2206 2600kv Props: HQProp 5x4.3x3 V1S FPV Cam: Runcam Racer RX: TBS Crossfire Nano vTX: FuriousFPV Stealth Race Antenna: Lumenier AXII Stubby Batteries: Swaytronic, KDlipo RACE 4 ---------------- Frame: FPVFrame.ch RaceX Flight controller: FuriousFPV Fortini OSD rev 2 ESCs: Hobbywing XRotor 4-in-1 40A dshot600 Motors: XNova Lightning 2206 2600kv Props: HQProp 5x4.3x3 V1S FPV Cam: Runcam Micro Swift 2 RX: TBS Crossfire Nano vTX: TBS Unify Pro Nano Antenna: Linear dipole Batteries: Swaytronic, KDlipo Other stuff: ========= Transmitter: FrSky Taranis Q X7 + M7-R Race Gimbal TX Module: TBS Crossfire TX w/ Diamond Antenna Ground station: Clearview Racing 5.8GHz Video antennas: VAS Pepperbox + Crosshair Goggles: Aomway Commander V1 Bag: LowePro QuadGuard BP X2