What should I do with a puffed LiPo battery?

Stop using it. Unplug it, put it on a non-flammable surface or in a LiPo bag away from anything that burns, and watch it for half an hour. If it stays cool and quiet, store it in the bag at room temperature, never charge it again, and take it to a battery or e-waste drop-off once it is discharged and its leads are taped.

Can I still fly a slightly puffed LiPo?

We don't recommend it. Many pilots do fly slightly puffed 1S whoop packs until they die, but a puffed cell has already broken down inside, holds less charge and sags harder. Indoors, where a whoop usually flies, a failing pack sits next to curtains and sofas. Retire it.

Why do LiPo batteries puff up?

The electrolyte inside breaks down and gives off gas. The usual causes are flying the pack too low, storing it fully charged, heat (Indian summers, hot cars, charging straight after a flight), overcharging, crash damage and plain age. Storage voltage and landing earlier prevent most of it.

Puffed LiPo battery: what to do, and why it happened

A puffed LiPo is a battery whose pouch has swollen with gas. On a whoop pack you notice it as a pack that no longer slides into the strap, a pillowy feel when you press it, or wrap that has gone tight and shiny. It means the cell has started breaking down inside. The good news: a puffed pack is a warning, not a fire, as long as you handle it calmly.

This guide covers what to do right now, whether "a little puffy" is OK to fly, how to get rid of it in India, and how to stop it happening again.

The next ten minutes

1. Unplug it
   □ From the quad, the charger or the parallel board

2. Move it somewhere that can't burn
   □ Tile floor, concrete balcony, a metal tin, or inside a LiPo bag
   □ Away from beds, curtains, sofas and the door you'd leave through

3. Watch it for half an hour
   □ Feel for heat from a distance first, then lightly
   □ Hissing, a sweet chemical smell or smoke: step back and keep people away

4. Once it stays cool and quiet
   □ Tape the connector
   □ Label it "DO NOT CHARGE" and keep it in the bag

If it is getting hotter, hissing or smoking, don't pick it up. Keep everyone clear, open windows, and let it burn out on the non-flammable surface. If the fire spreads or reaches anything else, call the fire service on 101. Never puncture or squeeze a puffed pack to "let the air out": that lets oxygen meet the chemistry inside.

Slightly puffed or properly puffed?

What you see	What it means	What to do
Soft and warm straight after a hard flight, flat again once cool	Normal heat expansion, pack is working hard	Let it cool before charging; check it again when cold
Slightly rounded even when cold	Gas has formed; capacity is going	Retire it from indoor flying; plan to dispose
Pillow-shaped, wrap stretched, won't fit the strap	Badly degraded cell	Retire now; don't charge it again
Puffed plus a dent, cut, burnt smell or melted connector	Damaged cell	Isolate in a LiPo bag outdoors-safe; dispose soon

Many pilots fly lightly puffed 1S packs until they stop holding a charge. We don't recommend it, mostly because whoops fly indoors: if a tired pack fails, it fails a metre from your curtains. A 1S pack costs less than the risk.

Why it happened

Gas forms when the electrolyte inside breaks down. These are the usual causes, roughly in the order we see them on whoop packs:

Cause	How it happens	The fix
Flying too low	Pushing past the voltage alarm "for one more lap"	Land at your alarm; on 1S, land around 3.5 V resting
Stored full	A charged pack left for days, often after a cancelled session	Bring packs to storage voltage (about 3.8 V) if you won't fly within a day or two
Heat	Charging hot packs, summer balconies, cars, sunny windowsills	Cool packs before charging; store them in the coolest room
Overcharging	Wrong mode (LiHV on a normal LiPo), cheap chargers	Match the charge mode to the pack; charge where you can see it
Crash damage	A hit that dents the pouch	Inspect packs after hard crashes; retire dented ones
Age	Hundreds of cycles, mostly at high current	Expect whoop packs to fade over a season of regular flying

India adds two of its own. Summer heat speeds up every one of these, so a fleet that survives winter can puff in May. And surface shipping means a pack may sit in a hot depot for days. A pack that arrives puffed is a warranty claim, not a habit problem: document the unboxing before you plug it in.

Disposing of it in India

Puffed packs are not household waste. The short version:

Discharge it fully with a charger that has a discharge mode, attended.
Tape the connector so it can't short in a bin bag.
Take it to a battery or e-waste collection point. Many cities list them on the municipal corporation's site, and local pilots usually know which recyclers accept hobby LiPos.

Until then it lives in a LiPo bag or metal tin, not loose in a drawer with screwdrivers. The full workflow, including why saltwater "discharge" tips are a bad idea at home, is in how to dispose of LiPo batteries. Don't courier a damaged pack anywhere: battery shipping rules apply to dead packs too.

Habits that prevent the next one

□ Land at the voltage alarm, every pack
□ Let packs cool to room temperature before charging
□ Storage voltage after every session you don't fly again the same day
□ Charge in the right mode (LiPo vs LiHV), where you can see it
□ No packs in cars, on sunny sills or on summer balconies
□ Rotate the fleet so the same two packs don't do all the work

Owning enough packs helps more than it sounds. With four to six packs you aren't tempted to squeeze the last volts out of the only two you have. See how many LiPo batteries you need.

Bottom line

A puffed pack is retired, not repaired. Unplug it, park it somewhere that can't burn, watch it, then discharge and drop it at an e-waste point. Prevention is three habits: land at the alarm, store at storage voltage, keep packs out of the heat.

Bench

Storage checkers, LiPo bags and spare whoop packs: the Bench.

FAQ

What should I do with a puffed LiPo battery?: Stop using it. Unplug it, put it on a non-flammable surface or in a LiPo bag away from anything that burns, and watch it for half an hour. If it stays cool and quiet, store it in the bag at room temperature, never charge it again, and take it to a battery or e-waste drop-off once it is discharged and its leads are taped.
Can I still fly a slightly puffed LiPo?: We don't recommend it. Many pilots do fly slightly puffed 1S whoop packs until they die, but a puffed cell has already broken down inside, holds less charge and sags harder. Indoors, where a whoop usually flies, a failing pack sits next to curtains and sofas. Retire it.
Why do LiPo batteries puff up?: The electrolyte inside breaks down and gives off gas. The usual causes are flying the pack too low, storing it fully charged, heat (Indian summers, hot cars, charging straight after a flight), overcharging, crash damage and plain age. Storage voltage and landing earlier prevent most of it.