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Follow international aviation rules: individual lithium‑ion external battery packs rated up to 100 Wh are permitted in the cabin without prior approval; devices rated between 100 Wh and 160 Wh require explicit airline approval and are normally limited to two units per passenger; any unit above 160 Wh is forbidden both in the cabin and in checked baggage.
If the label shows milliampere‑hours (mAh) only, convert to Watt‑hours with this formula: Wh = (mAh × V) / 1000. Use the cell nominal voltage (typically 3.7 V) for the calculation. Example: a 20,000 mAh pack at 3.7 V ≈ 74 Wh, which falls below the 100 Wh threshold.
Protect terminals against short circuits (original packaging, terminal covers, or insulating tape). Keep all spare external chargers and loose lithium cells in the cabin, switched off, and separate from checked items. Devices may need to be presented individually during security screening.
Obtain written approval from the carrier before travel if any unit falls in the 100–160 Wh band, and declare such items at check‑in. Consult the specific UK flag carrier’s website and the latest IATA guidance for final confirmation of allowable quantities and any route‑specific restrictions.
Battery pack rules for UK carriers (BA) – immediate guidance
Keep spare lithium-ion battery packs in carry-on bags; do not place loose spare cells or external battery units in checked baggage.
Capacity limits (Wh): up to 100 Wh – allowed without prior approval; 100–160 Wh – maximum two spare units per passenger and airline approval required; above 160 Wh – forbidden in both cabin and hold.
If only mAh is printed, convert to watt-hours using Wh = (mAh × nominal voltage) / 1000. Use 3.7 V as the typical nominal voltage for consumer packs. Examples: 5,000 mAh ≈ 18.5 Wh; 10,000 mAh ≈ 37 Wh; 20,000 mAh ≈ 74 Wh; 27,000 mAh ≈ 100 Wh; 43,000 mAh ≈ 160 Wh.
Labeling and protection: keep units in original packaging where possible, or place each in a separate plastic pouch/insulating sleeve; cover terminals with tape or use terminal caps to prevent short circuits; keep devices switched off during boarding and storage.
Installed batteries (inside phones, laptops, cameras) are generally permitted in checked bags but carrying them in the cabin reduces risk and inspection delays; spare packs must always remain with the passenger in the cabin.
Approval and declaration: for any pack above 100 Wh contact the carrier well before travel to obtain written approval; present the approval paperwork and the pack at check-in or security if requested. Carriers may refuse acceptance even with approval.
At airport security expect screening of high-capacity units; PACKETS showing damage, swelling or leaking will be confiscated. Carry a secondary small bag or protective case for screening removal of fragile cells.
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Are portable chargers allowed in carry-on on BA flights?
Recommendation: Store all spare lithium-ion battery packs in carry-on; packs up to 100 Wh are permitted without airline approval; packs from 100 Wh up to 160 Wh require airline approval and are limited to two spares per passenger; any pack over 160 Wh is prohibited.
Watt-hour calculation
Calculate watt-hours: Wh = (mAh ÷ 1000) × nominal voltage. Examples: 10,000 mAh at 3.7 V = 37 Wh; 20,000 mAh = 74 Wh; 27,000 mAh ≈ 99.9 Wh (borderline to 100 Wh). If the unit lists mAh but not Wh, perform this calculation or consult manufacturer specifications.
Packing and security tips
Keep terminals insulated (cover exposed contacts with tape or retain original packaging), place each spare battery in a separate protective pouch, and stow all spares in cabin baggage only; batteries installed inside devices may be carried in the cabin or hold, but spare cells are not permitted in the hold. Declare unclear ratings at check-in and contact BA customer service to request approval for 100–160 Wh items. Non-compliant items found at security will be confiscated and may result in denied boarding.
Wh limits: what capacity is allowed in carry-on on BA?
Direct answer: Cells rated up to 100 Wh are permitted in the cabin without carrier approval; units between 100 Wh and 160 Wh require written airline approval and are limited to two spare units per passenger; cells exceeding 160 Wh are prohibited on passenger aircraft (both cabin and checked) unless shipped as approved cargo.
Calculating and identifying Wh
- Formula: Wh = (mAh × V) / 1000. Use the rated voltage printed on the battery or pack.
- Typical examples (3.7 V nominal): 10,000 mAh → 37 Wh; 20,000 mAh → 74 Wh; 30,000 mAh → 111 Wh (approval required).
- If only mAh is shown and no voltage, assume 3.7 V only for an estimate; obtain manufacturer specs for certainty when near limits.
Operational guidance and documentation
- Spare lithium-ion units must be carried in the cabin; do not place spare units in checked baggage.
- Installed batteries (inside devices) are acceptable subject to the same Wh thresholds; major-capacity equipment (>160 Wh) requires carrier/cargo arrangements.
- For 100–160 Wh items: request written approval from BA at least 48 hours before departure, provide Wh rating, model/serial and number of units; retain approval confirmation for inspection.
- Terminal protection: cover exposed terminals (tape, original packaging or individual plastic sleeves) and ensure items are protected from short-circuit and damage.
- Security screening: keep units accessible for inspection and, if asked, be prepared to power on the device containing the cell.
- Carry a printed specification sheet or screenshot showing Wh ratings when capacity is not obvious from the label.
How to convert mAh to Wh to check your portable battery’s allowed rating
Use Wh = (mAh × V) / 1000; if voltage is not printed, assume 3.7 V (nominal lithium‑ion cell voltage).
- Locate the label: find mAh and the voltage (V). If the label already shows Wh, use that number.
- Apply the formula: Wh = (mAh × V) / 1000. Example: 10,000 mAh at 3.7 V → (10,000 × 3.7) / 1000 = 37 Wh.
- If only mAh at 5 V (output) is provided, this is output capacity. Convert to Wh_out = (mAh_5V × 5) / 1000, but prefer the internal cell voltage value (typically 3.6–3.85 V) for the true Wh used by regulators.
- Round up to the nearest whole Wh when comparing with airline thresholds. Treat any calculated Wh slightly above a limit as over the limit for safety.
- Quick reference conversions (using 3.7 V): 5,000 mAh ≈ 18.5 Wh; 10,000 mAh ≈ 37 Wh; 20,000 mAh ≈ 74 Wh.
- Threshold benchmarks: ~27,000 mAh ≈ 100 Wh; ~43,200 mAh ≈ 160 Wh.
- If the pack lists only Wh, use that figure. If internal voltage is 3.85 V (some newer cells), recalc with 3.85 V for greater accuracy.
- If calculation yields a Wh close to regulatory bands, keep the manufacturer specification or a photo of the label handy for verification at check‑points.
Packing rules: how to transport and protect portable chargers in carry-on
Store portable chargers inside the carry-on bag in individual non-conductive sleeves; insulate exposed terminals with electrical tape, heat-shrink tubing or original terminal covers before packing.
Terminal protection
Apply a single layer of electrical tape across each terminal so metal contacts are fully covered; alternatively use commercial plastic terminal caps. Keep each unit inside a soft pouch or zippered compartment to prevent rubbing against keys, coins or other metallic items.
Placement and storage
Place battery packs in a padded pocket near the top of the carry-on, separated from heavy items that could crush the casing. For multiple high-capacity units, use a fire-resistant pouch or metal container and keep them individually wrapped to avoid contact between terminals.
Segregate any damaged, swollen or leaking units in a sealed plastic bag and notify airline personnel before boarding; do not insert compromised cells into devices. When traveling with several spares, distribute them across multiple carry-on pieces rather than concentrating all units in one bag.
Approval and declaration: when to get airline permission for high-capacity battery packs
Obtain explicit carrier approval for any lithium‑ion external battery pack above 100 Wh. Units rated 100–160 Wh require prior permission and are normally limited to two units per passenger; units exceeding 160 Wh must be shipped as cargo and are not permitted in the cabin or checked baggage.
How to request permission
Contact the carrier’s dangerous-goods or special cargo desk at least 72 hours before departure and request written authorization. Provide the item’s Wh rating, voltage and mAh (or the mAh→Wh conversion), manufacturer model and serial number, quantity and whether cells are installed in equipment or are spares. Attach clear photos of the label and the manufacturer’s specification sheet or MSDS when possible. Keep the written approval (email screenshot or printout) to present at check-in and security; without authorization agents will refuse carriage.
Documentation and declaration procedure
Prepare an itemised list (model, serial, Wh), label photographs and the completed dangerous‑goods declaration or carrier form. Declare the items to the check‑in agent and present approval documentation; security may request removal of batteries from devices for inspection. For professionals transporting multiple high‑capacity units, store documentation and batteries where staff can inspect them quickly–using a dedicated camera rucksack such as the best travel photography backpack keeps items accessible. For an unrelated technical reference, see which molecule remains in the nucleus during protein synthesis.
Consequences of failing to declare include confiscation, fines, denied boarding and flight delays. Approval must cover the entire itinerary (all carriers on connecting flights); do not assume on‑the‑spot acceptance at the airport.
Checked baggage: portable chargers must not be placed in the aircraft hold
Do not place portable chargers or spare lithium-ion battery units into checked baggage; they are required to be carried in the passenger cabin so crew can access and isolate them immediately.
Main hazards in the cargo compartment
Most external battery packs use lithium‑ion cells (UN3480). In the hold mechanical crushing, terminal shorting, pressure and temperature swings increase the probability of cell damage and internal short circuits. A damaged cell can enter thermal runaway, producing intense heat, flaming particles and copious toxic smoke that may overwhelm cargo fire suppression and spread to neighbouring bags or aircraft systems.
Cargo compartments are inaccessible during flight, so a developing battery fire cannot be controlled by crew using portable extinguishers or manual isolation. Fire detection and suppression systems in many cargo bays are designed for conventional fuel fires and may not prevent re‑ignition of lithium battery thermal events.
| Hazard | Operational consequence / rationale for cabin carriage |
|---|---|
| Mechanical damage during loading/unloading | Crushed cells can short and ignite; crew access in cabin allows immediate isolation and fire response |
| Terminal contact with metal objects | External short circuits are common cause of battery fires; terminals are easier to protect and inspect in carry‑on |
| Thermal runaway and re‑ignition | Cargo suppression may not extinguish or prevent re‑ignition; cabin stowage enables crew intervention and containment |
| Regulatory prohibition and safety policy | IATA/ICAO/CAA rules require spare lithium batteries to remain in the cabin; batteries above defined Wh thresholds need prior approval or are forbidden |
Regulatory foundations and consequences
IATA Dangerous Goods Regulations and ICAO Technical Instructions classify loose lithium batteries as restricted for checked carriage; most national aviation authorities align with this. Batteries rated between 100 Wh and 160 Wh typically require carrier approval, while those above 160 Wh are prohibited for passenger carriage in either compartment. Failure to comply frequently results in off‑loading of the bag, refusal of carriage and potential fines.
