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Power banks, 20,000 mAh class
price per 100 Wh How we compare Buying guide ↓
- Wh from mAh
- mAh × 3.7 ÷ 1,000
- Carry-on limit
- 100 Wh · 160 Wh with approval
- Usable share of mAh
- About 60–70 %
- Output needed
- Phone 20–30 W · laptop 65 W+
20,000 mAh classEnergy 55–100 WhPhone charges 3–5Carry-on Yes, up to 27,000 mAhCompare all 4 types
Compare the types
All types- Mini (under 7,000 mAh)from $81.08Energy: About 18 WhPhone charges: About 1Carry-on: YesBest for: Pocket carry, a day of maps and photos14 listings
- 10,000 mAh classfrom $45.92Energy: About 37 WhPhone charges: 1.5–2.5Carry-on: YesBest for: Everyday carry at about 200 g46 listings
- 20,000 mAh classfrom $27.05Energy: 55–100 WhPhone charges: 3–5Carry-on: Yes, up to 27,000 mAhBest for: Several days, two people, a tablet54 listings
- 30,000 mAh and upfrom $38.73Energy: Over 100 WhPhone charges: 4 or moreCarry-on: Airline approval, to 160 WhBest for: Check printed Wh and flight rules first1 listing
Filters (1)
| Product | $ / 100 Wh ▲ | Max output (W) | Package | Capacity | Kind | Type | Rating · Reviews |
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| Product | $ / 100 Wh ▲ | Max output (W) | Package | Capacity | Kind | Type | Rating · Reviews | |
|---|---|---|---|---|---|---|---|---|
| UGREEN 22.5W Power Bank Slim 20000mAh USB C Portable Charger PD3.0 20,000 mAh · 74 Wh · 4.6 / 5 Max output (W): 22.5 Capacity, output & details
| $54.04per 100 WhBest value | 22.5 | $39.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.6 (4.3K) | |
| Charmast 20000mAh Power Bank 22.5W Built in 4 Cables, Slim Portable Charger 20,000 mAh · 74 Wh · 4.5 / 5 Max output (W): 22.5 Capacity, output & details
| $56.74per 100 Wh | 22.5 | $41.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.5 (6.9K) | |
| INIU Power Bank, Smallest 20000mAh 22.5W Fast Charging Portable Charger 20,000 mAh · 74 Wh · 4.7 / 5 Max output (W): 22.5 Capacity, output & details
| $56.74per 100 Wh | 22.5 | $41.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.7 (31.4K) | |
| Charmast 20000mAh Power Bank 22.5W Built in 4 Cables, Slim Portable Charger 20,000 mAh · 74 Wh · 4.5 / 5 Max output (W): 22.5 Capacity, output & details
| $56.74per 100 Wh | 22.5 | $41.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.5 (6.9K) | |
| Charmast 20000mAh Power Bank 22.5W Built in 4 Cables, Slim Portable Charger 20,000 mAh · 74 Wh · 4.5 / 5 Max output (W): 22.5 Capacity, output & details
| $58.09per 100 Wh | 22.5 | $42.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.5 (6.9K) | |
| INIU Power Bank, Smallest 20000mAh 22.5W Fast Charging Portable Charger 20,000 mAh · 74 Wh · 4.7 / 5 Max output (W): 22.5 Capacity, output & details
| $62.15per 100 Wh | 22.5 | $45.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.7 (31.4K) | |
| INIU 20000mAh Portable Charger, Smaller 45W Fast Charging Travel Power Bank 20,000 mAh · 74 Wh · 4.4 / 5 Max output (W): 45Most powerful Capacity, output & details
| $71.61per 100 Wh | 45Most powerful | $52.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.4 (1.9K) | |
| INIU 20000mAh Power Bank, Smaller 45W Fast Charging Travel Portable Charger 20,000 mAh · 74 Wh · 4.4 / 5 Max output (W): 45Most powerful Capacity, output & details
| $71.61per 100 Wh | 45Most powerful | $52.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.4 (1.9K) | |
| INIU 20000mAh Power Bank, Smaller 45W Fast Charging Travel Portable Charger 20,000 mAh · 74 Wh · 4.4 / 5 Max output (W): 45Most powerful Capacity, output & details
| $71.61per 100 Wh | 45Most powerful | $52.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.4 (1.9K) | |
| UGREEN CCC Certified 22.5W Power Bank Slim 20000mAh PD3.0 Portable Charger 20,000 mAh · 74 Wh · 4.4 / 5 Max output (W): 22.5 Capacity, output & details
| $80.82per 100 Wh | 22.5 | $59.81Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.4 (38) | |
| INIU Portable Charger, Compact 20000mAh Fast Charging Power Bank 20,000 mAh · 74 Wh · 4.4 / 5 Capacity, output & details
| $85.12per 100 Wh | — | $62.99Package price | 20,000 mAh · 74 Wh | Standard | 20,000 mAh class | 4.4 (3.1K) |
$71.61 per 100 Wh median of 54 in-stock listings.
Per 100 Wh of nominal cell energy: mAh × 3.7 V, or the stated Wh where it agrees within 20 %; power stations by their stated Wh. ~ marks a stated Wh set aside, or a title that names several capacities.
Power banks, 20,000 mAh class: what to know before you buy
20,000 mAh class. 15,000–27,999 mAh, about 55–100 Wh: three to five phone charges or one top-up of a 13-inch laptop at 65 W and up, 350–500 g. 26,800–27,000 mAh is the largest size under the 100 Wh airline line, which is why so many banks stop there. Expect a display and two USB-C ports at this size, and check the input watts, since 10 W takes all night.
A USB battery for phones, tablets, earbuds and small gadgets: everything without a magnet, a built-in cable, a solar panel or laptop-level output. Buyers most often expect the mAh on the box to equal phone charges, when only about 60–70 % of it reaches a 5 V port and a modern phone holds 4,000–5,000 mAh, and they buy by mAh alone when the output and input watts decide how the bank feels in use. Since 2025–2026 many airlines also forbid using a bank on board, so “I’ll charge on the plane” no longer holds.
Specs and terms that matter
Capacity: mAh and Wh
The headline mAh is the charge of the cells at their nominal 3.7 V; 10,000 mAh is about 37 Wh, 20,000 mAh about 74 Wh and 27,000 mAh about 100 Wh, the airline line. Watt-hours are what airlines read and what a listing should print; a bank with no Wh printed on the case is harder to fly with, and some carriers refuse it.
Rated capacity at 5 V
A second, smaller figure such as “rated 12,000 mAh (5 V/3 A)” beside a 20,000 mAh headline: what the USB port can deliver after the step-up to 5 V and 10–20 % converter loss. Stiftung Warentest measured a 20,100 mAh bank at the equivalent of 14,760 mAh in 2022, about 73 %, and its January 2026 test of 24 banks puts 20,000 mAh models at about 70 Wh usable. Normal, not a fault.
Output watts, per port and combined
USB-C outputs run 20, 22.5, 30, 45, 65 and 100 W. “PD 20 W” is iPhone class, “22.5 W” is the Huawei and Quick Charge style figure, “30–45 W PPS” is Samsung and Pixel class, 65 W and up charges laptops. The combined figure is not the per-port figure: most banks drop every port to a lower profile when two devices are plugged in.
Protocols: PD, PPS, QC
USB Power Delivery is the universal standard; iPhones charge on plain PD at roughly 20–30 W. Samsung’s and Google’s 45 W fast charging uses PPS (Programmable Power Supply, part of PD 3.0), so a PD-only bank charges those phones more slowly. Quick Charge 3.0 serves older Android phones over USB-A.
Input watts (recharge speed)
How fast the bank itself refills. A 10 W input takes 5–7 h for 20,000 mAh; 30–65 W input refills it in 1.5–2 h. Input drops sharply above about 80 % as the cells enter constant-voltage charging, so a “140 W” bank at 91 % drawing 40 W is behaving normally.
Ports and low-current mode
Two USB-C ports (both in and out) plus one USB-A is the common layout; Lightning is rare now. A low-current or trickle mode keeps the bank awake for earbuds, watches and trackers, which draw so little that many banks read “nothing connected” and switch off.
Cells, weight and the fake check
18650 or 21700 cylindrical cells make a dense, rounded brick; lithium-polymer pouches make slim banks. A finished bank holds about 50–75 mAh per gram, so 10,000 mAh weighs about 180–230 g and 20,000 mAh 325–450 g. A claimed 50,000 mAh under 700 g, or anything above 100,000 mAh, is physically impossible.
Display
A percentage readout is common from 10,000 mAh; a live watts-in and watts-out display is expected on 20,000 mAh banks and up, and shows whether phone and bank negotiated the fast profile.
Safety marks
UL 2056 is UL’s outline of investigation for lithium-ion power banks (US and Canada); CE or UKCA and a UN 38.3 transport test report are the usual European marks; Japan requires the PSE mark on mobile batteries under the DENAN Act since 1 February 2019; China requires a 3C mark to fly domestically since 28 June 2025. Many good banks carry only CE and UN 38.3, so a missing UL mark alone says nothing. Marks on a listing are the seller’s statement.
Cycle life and warranty
Makers rarely state cycle life; 500 full cycles is the old assumption and 1,000 or more is common now. Keeping the bank permanently on a charger ages the cells faster. Warranties of 12–24 months are typical and often exclude normal capacity loss.
Before you buy
- Look for the Wh printed on the case and in the listing, and whether it is 100 Wh or under: 27,000 mAh is about 100 Wh, 30,000 mAh is about 111 Wh and needs airline approval.
- Match the output to the phone: PD 20 W or more for an iPhone, PPS at 25–45 W for a Samsung or Pixel. If two devices charge at once, read the combined figure and the per-port drop.
- Read the input watts: 10 W means an overnight refill for 20,000 mAh, 30–65 W a refill in 1.5–2 h.
- Weigh the size against the use: 10,000 mAh at about 200 g covers a day for most people; 20,000 mAh at 350 g or more suits several days, two people or a tablet.
- Check the weight against the capacity: 20,000 mAh should weigh 300 g or more. A 50,000 mAh bank under 700 g is a fake claim.
- Check the model number against the maker’s recall page and, in the US, cpsc.gov; prefer a bank with a traceable brand, a legible serial number and a stated warranty.
- For a bank of 65 W and up, check that the cable in the box is 5 A e-marked; a plain USB-C cable carries 60 W.
- Look for a low-current mode if earbuds, a watch or a tracker will be charged from it.
Myths and mistakes
- 20,000 mAh is not four phone charges: it is three to five for a 4,000–5,000 mAh phone, fewer when charging at 30 W, because heat and conversion take their share.
- Bigger is not better for daily carry: in long r/anker and r/onebag threads 10,000 mAh is the consensus everyday size, 5,000 mAh covers a day of maps and photos, and 20,000 mAh and up is for laptops, camping, long-haul trips and outages.
- A cheap no-name bank is not “the same cells”: such listings rarely print Wh, cannot be checked against a recall list and inflate mAh; the weight check exposes most of them.
- A fast-charge logo does not mean the phone charges fast: only a matching protocol does, PD for iPhone, PPS for Samsung and Pixel, Quick Charge for older Androids.
- Recalls hit the biggest brands because they sell the most and report to the CPSC; a no-name bank is rarely recalled because nobody reports it, which is not the same as being safe.
Questions people ask
How many times will a 10,000 mAh power bank charge my phone?
About 1.5–2.5 times for a 4,000–5,000 mAh phone, and a 20,000 mAh bank three to five times. Only about 60–70 % of the headline mAh reaches the phone: the cells are counted at 3.7 V, the port delivers 5 V or more, and the converter and cable lose 10–20 %. Test-Achats measured a 10,000 mAh bank charging a 5,000 mAh Galaxy S24 Ultra 1.22 times, not twice.
Can I take a 20,000 or 30,000 mAh power bank on a plane?
Under the ICAO Technical Instructions, which the FAA, EASA and IATA follow, a power bank travels in carry-on only: up to 100 Wh without approval, 101–160 Wh with the airline’s approval and at most two, nothing above 160 Wh. 20,000 mAh (74 Wh) and 27,000 mAh (about 100 Wh) pass; 30,000 mAh (111 Wh) needs approval; 43,000 mAh and up is over the ceiling. ICAO’s Addendum No. 1 to the 2025–2026 edition, applicable from 27 March 2026, adds: no more than two power banks per person, each protected against short circuit, none recharged on board. Airlines differ and may be stricter; the airline’s current rule applies.
Can I use or charge a power bank during the flight?
On a growing number of airlines, no. Hong Kong’s Civil Aviation Department banned use on board from 7 April 2025, Korean carriers after the Air Busan fire of January 2025, Emirates from 1 October 2025, and Qantas, Jetstar and Virgin Australia from 15 December 2025. ICAO’s Technical Instructions addendum applicable from 27 March 2026 says a power bank must not be recharged on board and should not be used to charge a device, and IATA’s rules follow ICAO, so expect the rest to converge. Several airlines also want the bank in the seat pocket or under-seat bag, not the overhead bin. The airline’s current page is the rule.
What does “rated capacity” on the label mean?
The charge the 5 V port can deliver, printed beside the larger headline figure: “rated 12,000 mAh (5 V/3 A)” next to 20,000 mAh. It is smaller by arithmetic, since the same energy at 5 V is fewer mAh, plus 10–20 % converter loss. Compare banks on the figure measured the same way; a bank that prints both is being more open, not weaker.
How many watts does my phone need?
20–30 W covers an iPhone and most Androids; 45 W with PPS is the ceiling for the fastest Samsung and Pixel phones; a tablet uses 30–45 W; a laptop needs 65 W or more. More watts than the device accepts change nothing, since the device sets the pace.
Why is my power bank at 60 % after charging my phone once?
Usually because the phone kept running on the bank all night, with backups, syncing and the screen, on top of the 10–20 % conversion loss. It is the most common “my bank is broken” report, and in nearly every case the bank is fine. A bank that drains or fills in minutes is a different matter: that is a cell or battery-management fault, and the advice is to stop using it and claim the warranty.
How long does a power bank take to recharge?
Roughly the Wh divided by the input watts, times 1.3 for the taper at the end: 74 Wh at 18 W is about 5 h, at 45 W about 2 h. The input rating is only reached with a charger and cable that support it, and it drops sharply above about 80 %.
How long does a power bank last?
500–1,000 full charge cycles before the capacity drops noticeably, so several years of normal use. Cells age faster when kept at 100 % on a charger or stored hot; a bank left half charged in a drawer keeps best. Most warranties run 12–24 months and exclude normal wear.
Sources: ICAO Technical Instructions 2025–2026, Addendum No. 1 (27 March 2026), FAA PackSafe: lithium batteries, US CPSC: battery recalls, UL Solutions: portable power pack testing (UL 2056, UL 2743), Stiftung Warentest: 24 power banks tested (January 2026). Reviewed 19 Oct 2026. General information compiled from public sources, not safety or legal advice. Airline rules change often; your airline’s current rule is the one that applies.
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