Do you mean general info about power banks (how they work, how to pick one, safety and airline rules), or are you looking for product recommendations to buy? Below is a concise, practical guide covering both — capacity, features to look for, safety, and current Australian airline rules.

Quick summary

• Power banks store energy (lithium-ion or lithium-polymer) and output it to charge phones, tablets, laptops, etc.
• Choose capacity (mAh/Wh), output power (watts), safety features, and ports based on what you need.
• For air travel in Australia: power banks must be carried in carry‑on luggage; under 100 Wh is generally OK, 100–160 Wh requires airline approval, and >160 Wh is banned from passenger baggage. Always check your airline for any extra restrictions. (CASA.gov.au)

How power banks are specified (quick reference)

• mAh (milliamp-hours): common spec on power banks (e.g., 10,000 mAh). mAh alone doesn’t show energy until you know the battery voltage.
• Wh (watt-hours) = (V × mAh) / 1000. Use Wh when comparing energy or for airline rules. Example: a typical 3.7 V, 10,000 mAh bank ≈ (3.7 × 10,000) / 1000 = 37 Wh. (CASA.gov.au)

Choosing the right power bank

1. Capacity (how many charges?)

   • 5,000–10,000 mAh: one full phone charge (good for day trips, portable).
   • 10,000–20,000 mAh: multiple phone charges, occasional tablet top-ups.
   • 20,000+mAh: best for long trips or charging laptops (but heavier/ larger).
   • Remember real delivered capacity is ~60–85% of rated mAh due to conversion losses.

2. Output power and charging speed

   • USB-A vs USB-C: USB-C (Power Delivery, PD) supports higher wattages and faster charging.
   • For phones: 18–30 W PD is plenty.
   • For laptops: look for PD 45–100 W output (and confirm laptop supports USB‑C charging).
   • If you want to charge a laptop and phone simultaneously, check total output limits.

3. Features to consider

   • Power Delivery (PD) and Quick Charge support for fast charging.
   • Pass-through charging (charges bank while it charges devices) — convenient but can stress battery; avoid overnight use.
   • Number/type of ports (USB‑C, USB‑A, AC outlet for some high-capacity banks).
   • Display or LED to show percent remaining.
   • Weight/size and build quality.
   • Manufacturer warranty, certifications (CE, FCC), and reputable brand.

4. Safety features

   • Overcharge, overdischarge, short‑circuit, overcurrent, and temperature protection.
   • Protection against swelling or overheating; avoid very cheap unbranded units.
   • Don’t use or carry swollen, damaged, or recalled banks. Dispose/recycle them properly. (CASA.gov.au)

Air travel rules (Australia) — key points (check airline before flying)

• Carry power banks only in carry‑on baggage (do NOT put them in checked luggage). Trained crew can better handle incidents in cabin. (CASA.gov.au)
• Watt-hour rules:
  • Under 100 Wh: generally allowed in carry‑on (check airline limits on quantity). (CASA.gov.au)
  • 100–160 Wh: allowed only with airline approval (usually max two spares). (Qantas.com)
  • Over 160 Wh: prohibited in passenger baggage (must be shipped as cargo/dangerous goods). (CASA.gov.au)
• Airlines may also ban using power banks on board or charging them from in‑seat USB/AC ports — many carriers tightened rules after recent incidents; check your airline’s page before flying. (news.com.au)

Practical buying checklist (short)

• Capacity: pick mAh that fits how many charges you need.
• Output: USB‑C PD for fastest, highest‑watt charging; match wattage to device (phones ~18–30 W, laptops often 45–100 W).
• Safety: built‑in protections, reputable brand, warranty.
• Size/weight: balance portability vs capacity.
• Airline compliance: if you travel, check the Wh rating or choose under 100 Wh to avoid approval requirements.

Usage & safety tips

• Don’t leave power banks charging unattended or overnight.
• Stop using if the unit becomes hot, swollen, or emits odor.
• Protect terminals (tape or original packaging) if required to carry spares and when storing.
• Buy from legitimate retailers — cheap, uncertified banks are higher risk. (CASA.gov.au)

If you want:

• I can convert any mAh rating to Wh for you (give the mAh and voltage if shown).
• Or I can search and compare current popular models available in Australia (I’ll need to look up products and latest prices). Which would you prefer?