Learn · batteries
1S vs 2S batteries
Drone batteries come in stackable cells — like juice boxes. 1S means one cell. 2S means two cells working together.
One cell is gentle: the drone floats around calmly, perfect for indoors. Two cells is double the push: faster, punchier, and better outside where wind tries to shove the drone around.
Why you care: 1S whoops are where nearly everyone starts — gentle enough to learn on. 2S is what you graduate to when the backyard starts calling.
The "S" is cells in series — each adds ~3.8V. More voltage = more motor speed = more punch.
What you actually need to know
- 1S (65–75mm whoops): 300–450mAh packs, 2.5–4 minute flights, tame and indoor-happy. You'll want 6–8 packs to keep a session going.
- 2S (80–85mm): roughly twice the punch; handles wind, climbs out of trouble, drains faster per gram. Outdoor territory.
- Connectors matter and don't mix: tiny whoops use BT2.0 or A30 plugs; 2S packs usually XT30. Your charger and packs must match your drone — check the spec table on any model page here.
- Battery care: store packs at "storage charge" (chargers have a button for it), stop flying when the drone gets mushy rather than squeezing the last volt, and retire puffy packs. Treated well, packs last 100–200 flights.
- Sag is the real spec: a pack's voltage droops under throttle — a fresh high-C pack holds voltage through a punch-out where a tired one folds. Consistent lap times come from consistent packs; rotate and label them.
- Weight math: on a 20g whoop, the pack is a third of takeoff weight. Racers often run the smallest pack that finishes the heat — 300mAh flies noticeably harder than 450 for the first two minutes.
- HV chemistry (LiHV, 4.35V/cell full) buys punch off the line at some cycle-life cost; most whoop packs are HV now.
- 2S discipline: double voltage quadruples the watts your fingers command — set your throttle curve and your expectations accordingly the first weekend.
- Series math: nS = n × cell voltage (LiHV: 4.35V full, ~3.8V nominal, 3.3V working floor). Power scales with V²/R for a fixed motor — the 1S→2S jump is dramatic because it's voltage-squared into the same winding.
- Internal resistance dominates whoop pack performance: tens of mΩ per cell at these sizes; sag = I×R lands directly on the FC/VTX rail. (It's why marginal packs brown out video systems on punch-out — a documented failure mode on 1S digital builds.)
- Connector contact resistance was the quiet revolution: PH2.0's ~20mΩ throttled early whoops; BT2.0/A30 cut that several-fold — same cell, visibly more punch.
- Energy vs power density: whoop cells trade capacity for discharge capability; the "C rating" is marketing shorthand — trust sag under a real load profile, not the label.