In-depth buying guides from the AST-Drones certified inspection desk.
Batteries are the consumable heart of a used drone deal — and the most misrepresented line item in private sales. A drone with two tired packs needs $240–400 of replacements on day one. Here's how to read the numbers that matter.
DJI intelligent batteries report cycle counts in-app: under 80 cycles is Excellent territory, 80–150 is Good with verification, over 200 needs justification. But cycles measure use, not condition. A pack stored fully charged in a hot garage for two years can test worse at 40 cycles than a fleet pack at 180. Which is why cycle count is a screening number, never a buying decision.
The only number that matters: measured capacity versus design capacity, tested under load. We bench-discharge every pack and publish the percentage — 90%+ is healthy, 80–89% is usable with price adjustment, below 80% gets replaced before sale. In a private deal, a 10-minute hover tells you the same story: compare actual flight time to the model's rated endurance. Details per model are on pages like our Mini 4 Pro battery expectations.
A pack can show decent total capacity while one cell drifts low — and imbalanced cells fail suddenly, mid-flight. In the DJI app's battery screen, cell voltages should sit within ~0.05V of each other under load. Wider spread means the pack is living on borrowed time regardless of cycle count.
Swelling is non-negotiable: set the pack on a flat surface — if it rocks or wobbles, walk away, no exceptions. Check contact pins for scorch marks, latches for firm engagement, and the shell for impact cracks. Heat after a normal charge is another quiet warning.
Every used drone negotiation is really a battery negotiation: deduct $100–130 per consumer pack (more for TB60/TB65 enterprise pairs) that fails these checks. Every drone in our used catalog ships with a written battery health report — cycle count, cell balance and tested capacity, per pack.
Over 200 cycles on consumer DJI packs needs exceptional tested capacity to justify; over 300 is replacement territory. But always weigh tested capacity over cycle count — a well-stored 150-cycle pack beats a abused 60-cycle one.
No. Swelling indicates internal gas from cell degradation — it's a chemistry problem, not a maintenance issue. Swollen packs should be retired and recycled, never flown or charged unattended.