For Lufthansa (and therefore also Air France / most EU–US routes under ICAO rules) the current rules are:
✔️ Power banks allowed
Max 2 power banks per passenger
Must be in carry-on only
Not allowed in checked baggage
Must be under 100 Wh each without approval
⚠️ Higher-capacity units
100–160 Wh → allowed only with airline approval
Above 160 Wh → not allowed at all
🚫 In-flight use rules (important for your PicoMuon)
Power banks cannot be used or charged during the flight on Lufthansa Group airlines
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What this means in practice for your PicoMuon setup
You can take:
2 × 99 Wh power banks (≈ 26,800 mAh each) → fully compliant
Or several smaller ones (e.g. 10,000–20,000 mAh)
But:
You cannot legally run a device continuously from a power bank during the flight under Lufthansa Group rules
Cabin crew may treat an actively-powered experiment as “use of power bank,” even if technically passive discharge
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Practical recommendation for your case (radio / muon logging)
For a long-haul flight experiment:
Use a single internal battery in the PicoMuon (if possible)
Or a single 100 Wh pack running externally but not “used actively” in flight terms
Avoid visible continuous “lab-style setup” using multiple packs
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