# Power banks: research notes Date: 2026-10-19. Scope: portable USB battery packs, including magnetic wireless (MagSafe / Qi2) banks and laptop-class banks. In the Zamana taxonomy these sit under machines/electronics `charger` with `charger_type: power_bank`. Quote labels: **verbatim** = the fetch returned the sentence in quotation marks; **fetched excerpt** = the fetch tool summarised or lightly reworded; **search excerpt** = the number came from a search-engine summary because the page itself would not load. ## Seed Seed run: example = car-tyres treadwear grade; persona = a cycling mechanic (compatibility, standards, the part that has to match). 1. The power-bank equivalent of treadwear is the mAh figure. It is on every listing, it is the number people compare on, and it needs a judgement attached: it is the cells' capacity at a nominal voltage the brand chooses (3.6 to 3.87 V in the teardowns below) and before conversion losses. Cross-brand comparison needs watt-hours, and even watt-hours need the measured conversion efficiency to become what a phone receives. Survived the data check: Wh is printed on most banks by law and the efficiency numbers exist from ChargerLAB. 2. What the cycling mechanic notices first is the part that has to match. Three parts: the cable (above 60 W needs a 5 A e-marked cable, above 100 W an EPR cable, and the headline wattage is often only reachable with the cable in the box); the phone's protocol (Samsung needs PPS, iPhone needs USB PD at 20 W or more, magnetic charging needs Qi2 or MagSafe); and the recharge side (a 140 W input only helps if you own a 140 W charger). Survived as notes inside the output and recharge facets and as vocabulary, not as separate facets. Dropped: serviceability and replaceable cells (no consumer bank offers them, no data), and proprietary Android protocols beyond PPS (present in the add-on enum already, low narrowing in Western catalogs). ## Sources and what each supports ### Regulators and standards bodies **IATA, Passengers Travelling with Lithium Batteries, 2026 edition (PDF, read locally with pdftotext)** https://www.iata.org/contentassets/6fea26dd84d24b26a7a1fd5788561d6e/passengers_travelling_with_lithium_batteries.pdf - verbatim: "Watt-hour rating, expressed in Wh ... is calculated by multiplying the rated capacity in ampere-hours by the nominal voltage (Wh = Ah x V)." - verbatim: "All lithium-ion batteries are required to have the Watt-hour rating marked on the outside of the battery case." - verbatim: "Passengers are limited to a maximum of two lithium-ion power banks not exceeding 100 Wh." "Power banks must not be recharged from an in-aircraft power supply." "Power banks should not be stored in the overhead lockers." "Power banks should not be used to provide power to other devices during taxi, take-off or landing." - verbatim: "Power banks (see below) are no longer referred to as 'spare batteries'." - verbatim: "Airlines prefer spare batteries and power banks to be at less than 25%." - verbatim: all batteries "must be of a type that meets the requirements of the UN Manual of Tests and Criteria, Part III, subsection 38.3." - Supports: Wh formula, Wh marking, the 100 Wh line, two-per-person, no in-flight recharging, UN 38.3 vocabulary. Confidence high. **IATA, Guidance for Operators: Changes Regarding Power Banks, 31 March 2026 (PDF, read locally)** https://www.iata.org/contentassets/90f8038b0eea42069554b2f4530f49ea/guidance-to-operators---power-banks.pdf - verbatim: "On 27 March 2026, the International Civil Aviation Organization (ICAO) introduced an addendum to the Technical Instructions, effective on the same day, regarding power banks." - verbatim: power banks "must not be recharged while onboard the aircraft (new requirement)"; "no more than two power banks may be carried per person (new requirement)". - verbatim: "The addendum provides for passengers to carry power banks of 100-160 Wh with the approval of the operator; however ... this provision will not be carried into the 68th edition of the DGRs." - verbatim: "Wireless power banks, which recharge another device through an electro-magnetic induction process are an emerging concern. As a recent innovation, they are susceptible to being counterfeited or mass produced without proper quality management/assurance programs or evidence of testing to and compliance with UN 38.3 tests ... several passengers have reported these power banks entering thermal runaway and self-destruction." - Supports: the date and content of the 2026 change, the 100-160 Wh band being withdrawn from 2027, and why the regulator flags wireless banks (counterfeiting, missing UN 38.3 evidence, passenger-reported thermal runaway; not coil heat). Confidence high. **49 CFR 175.10(a)(18), via Cornell LII** https://www.law.cornell.edu/cfr/text/49/175.10 - verbatim: "the Watt-hour rating must not exceed 100 Wh." - verbatim: "no more than two individually protected lithium ion batteries each exceeding 100 Wh, but not exceeding 160 Wh, may be carried per person as spare batteries in carry-on baggage." - verbatim: "Spare lithium batteries must be carried in carry-on baggage only." - Supports: the US rule (100 Wh, 101-160 Wh with approval, two, carry-on only). Confidence high. The FAA PackSafe page itself returned 403 twice; this is the regulation it summarises. **49 CFR 173.185, via Cornell LII** https://www.law.cornell.edu/cfr/text/49/173.185 - verbatim: "Beginning May 10, 2024, each lithium ion battery must be marked with the Watt-hour rating on the outside case." - verbatim: "The Watt-hour (Wh) rating may not exceed 20 Wh for a lithium ion cell or 100 Wh for a lithium ion battery." (the excepted-shipping threshold) - Supports: Wh is printed on the unit, so a label photo can backfill it. Confidence high. **TSA, What Can I Bring: Power banks** https://www.tsa.gov/travel/security-screening/whatcanibring/items/power-banks - verbatim: "Portable chargers or power banks containing a lithium ion battery must be packed in carry-on bags." - Supports: carry-on only. Confidence high. **USB Promoter Group, USB PD 3.1 announcement, 26 May 2021 (PDF, read locally)** https://www.usb.org/sites/default/files/2021-05/USB%20PG%20USB%20PD%203.1%20DevUpdate%20Announcement_FINAL.pdf - verbatim: "Prior to this update, USB PD was limited to 100W via a solution based on 20V using USB Type-C cables rated at 5A." - verbatim: "A choice of three new fixed voltages: 28V (above 100W), 36V (above 140W) and 48V (above 180W)". - verbatim: "up to 240W of power over the USB Type-C cable and connector." - Supports: anything above 100 W on one port is PD 3.1 EPR at 28 V or more. Confidence high. **UL Solutions, UL 2056 power bank testing** https://www.ul.com/insights/enhance-safety-power-banks-ul-2056-testing - verbatim: UL 2056 "covers critical safety aspects such as overcharge/discharge protection, short-circuit and overload testing, drop and impact resistance, and thermal safety." - Supports: what UL 2056 tests. Confidence high. **Compliance Gate, US power bank regulations** https://www.compliancegate.com/power-banks-regulations-united-states/ - fetched excerpt: "standards for power banks are mostly voluntary" but only "on paper"; "You can only sell power banks on Amazon that meet the listed safety standards" including "Option A: UL 2056 and UN 38.3". - verbatim: "Power banks must comply with UN 38.3 to be shipped both from the factory and distributed domestically." - Supports: UL 2056 voluntary in law, required by marketplaces; UN 38.3 is a transport test. Confidence medium. **ChargerLAB on the CAAC ban** https://www.chargerlab.com/chinas-civil-aviation-authority-bans-certain-power-banks-on-domestic-flights/ - verbatim: "effective June 28"; banned: "power banks that lack a clear China Compulsory Certification (3C) mark or have been recalled due to safety concerns"; reason: "multiple incidents this year where power banks and similar lithium battery products caught fire or emitted smoke during flights." **People's Daily Online** https://en.people.cn/n3/2025/0711/c98389-20339109.html - verbatim: "effective June 28, 2025"; banned: "those without a valid China Compulsory Certification (CCC) label, with an unclear 3C label, or subject to product recalls". - Supports: the 3C mark decides whether a bank can fly within mainland China. Confidence high (two sources agree). **Japan MLIT in-flight use ban (Time Out)** https://www.timeout.com/asia/news/japan-to-ban-in-flight-power-bank-usage-from-april-2026-heres-all-you-need-to-know-022526 - verbatim: "in-flight use or charging will be strictly prohibited" from April 2026; "High-capacity batteries exceeding 160Wh remain strictly banned, and devices below that threshold will be limited to two units per traveller". **AeroTime, airlines banning power banks** https://www.aerotime.aero/articles/airlines-banning-power-banks - fetched excerpt: all South Korean airlines stopped overhead-bin storage from 1 March 2025; Hong Kong airlines banned use and overhead storage from 7 April 2025; EVA Air, Thai, AirAsia, China Airlines, Singapore Airlines and Scoot require banks fully charged before flight and no in-flight use (March to April 2025). - Supports: in-flight use is now commonly banned, so the bank must be charged before boarding. Confidence medium-high. ### Mechanism and chemistry **Battery University BU-303** https://www.batteryuniversity.com/article/bu-303-confusion-with-voltages/ - verbatim: "The nominal voltage of lithium-ion is 3.60V/cell." "Some cell manufacturers mark their Li-ion as 3.70V/cell or higher. This offers a marketing advantage because the higher voltage boosts the watt-hours on paper". **Wikipedia, Lithium-ion battery (infobox)** https://en.wikipedia.org/wiki/Lithium-ion_battery - verbatim: specific energy "160–300 W⋅h/kg"; cycle durability "400–1,200 cycles"; nominal "3.6 / 3.7 / 3.8 / 3.85 V"; self-discharge "0.35% to 2.5% per month". - Supports: the nominal voltage a brand multiplies by is a choice between 3.6 and 3.85 V, so mAh is not comparable across brands. Confidence high. **Battery University BU-808** https://www.batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries - verbatim: "a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles." "The worst situation is keeping a fully charged battery at elevated temperatures." - Supports: cycle-life range, and why heat (pass-through, wireless) ages cells. Confidence high. **Wikipedia, Lithium iron phosphate battery** https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery - verbatim: specific energy "95–172 W⋅h/kg"; cycle durability "2,500–9,000 cycles"; nominal "3.2 V"; LFP "generally has higher decomposition temperatures". - Supports: LiFePO4 trades weight for life and thermal stability. Confidence high. Second source for the direction of the trade: Grepow / Jackery blog pages in search results give Li-ion 150-250 Wh/kg vs LiFePO4 90-120 Wh/kg and 4 to 5 times the cycle life (search excerpt). ### Specialist reviewers who measure **ChargerLAB review of Baseus 140W PD3.1 power bank** https://www.chargerlab.com/review-of-baseus-140w-power-bank - verbatim: "24000mAh/86.4Wh" (so the brand's nominal voltage is 3.6 V). - verbatim: efficiency "approximately 79.35%" at 5V3A, "84.49%" at 9V3A, "82.38%" at 12V3A, "86.47%" at 15V3A and 20V5A, "90.46%" at 28V5A. - verbatim: "When both USB-C1 and USB-C2 ports are used simultaneously, the C1 delivers 90W of power, while the C2 port provides 27W." Three ports: "90W, 9W, 7W." - verbatim: with an Apple 140W charger "100% in one hour and 6 mins." - Supports: deliverable energy is 79-90% of stored Wh and rises with output voltage; total wattage splits between ports; recharge time at 140 W input. Confidence high. **ChargerLAB review of AOHi Starship 40000mAh 140W** https://www.chargerlab.com/review-of-aohi-starship-40000mah-140w-power-bank-2 - verbatim: "Battery Capacity: 29.2V/5000mAh/146Wh"; "Weight≈900g", measured "about 916.2 g"; peak efficiency "about 121.6/146=82.92%". - Supports: banks above 100 Wh exist and weigh close to a kilogram; a second efficiency measurement. Confidence high. **ChargerLAB teardown of UGREEN Nexode 20000mAh 165W (PB726)** https://www.chargerlab.com/teardown-of-ugreen-nexode-20000mah-165w-power-bank-with-retractable-usb-c-cable-pb726 - verbatim: "Battery capacity: 20000mAh"; "Rated lithium-ion battery energy: 72Wh (14.4V 5000mAh)"; "Rated capacity: 11600mAh (TYP 5V 7A)"; cells "model INR21700-5000 from SunPower, with a nominal voltage of 3.6V"; "The weight is about 534 g"; cells "retain over 70% capacity even after 1,000 full charge cycles" (manufacturer claim). - Supports: rated capacity at 5 V is 58% of the headline mAh on this unit; four 21700 cells in a high-power bank; a built-in retractable cable is a listed feature. Confidence high. **ChargerLAB teardown of CUKTECH 10000mAh 30W (PB100)** https://www.chargerlab.com/teardown-of-cuktech-10000mah-30w-power-bank-pb100 - verbatim: "10000mAh", "about 36.5Wh"; two EVE "INR21700/50E" cells; "about 196 g". - Supports: a 10,000 mAh bank is about 36-37 Wh and about 200 g. Confidence high. **ChargerLAB teardown of Xiaomi 22.5W 5000mAh magnetic wireless bank (WPB0507S)** https://www.chargerlab.com/teardown-of-xiaomi-22-5w-5000mah-magnetic-wireless-power-bank-wpb0507s - verbatim: "19.35Wh, 3.87V, 5000mAh"; rated "5V 3000mAh"; cell "sourced from LS, model SP526578SR" (the article does not say pouch, polymer or soft-pack; corrected after the blind check); wireless "15W max"; "122 g"; "8.87 mm" thick. - Supports: a single-cell 5,000 mAh magnetic bank at 15 W wireless and about 120 g; the nominal voltage here is 3.87 V; rated capacity 60% of headline mAh. Confidence high. **ChargerLAB teardown of Anker Nano 10000mAh magnetic wireless charger power bank (A110Z)** https://www.chargerlab.com/teardown-of-anker-nano-10000mah-magnetic-wireless-charger-power-bank-a110z/ - verbatim: "39.1Wh"; two ATL "soft-pack cells", model "606072G", "5000 mAh" each, "nominal voltage is 3.91 V", "rated energy of 19.55 Wh"; "supports Qi2 15W fast wireless charging"; "238.7 g"; "about 21.88 mm" thick. - Supports: the 10,000 mAh end of magnetic packs, the soft-pack (pouch) format, Qi2 15 W. Confidence high. **ChargerLAB teardown of Xiaomi 10000mAh magnetic power bank (WPB1007ZX)** https://www.chargerlab.com/teardown-of-xiaomi-10000mah-magnetic-power-bank-wpb1007zx - verbatim: "Rated Energy: 39.1Wh (7.82V 5000mAh)"; "Rated Capacity: 5900mAh (5V 3A)"; two ATL cells "5000 mAh, a nominal voltage of 3.91 V, and an energy of 19.55 Wh"; "15W Max"; "about 225.6 g"; "about 20.32 mm" thick. - Supports: a second 10,000 mAh magnetic pack; rated capacity 59% of headline. Confidence high. **ChargerLAB pass-through test method** https://www.chargerlab.com/chargerlab-power-z-km003c-tests-power-bank-pass-through-charging-performance-with-tutorial - verbatim: "Simultaneous charging and discharging is a common feature in modern power banks"; "Monitor the temperature of the power bank during testing. High temperatures may trigger power throttling and reduce output." - Supports: pass-through exists, is testable, and heat is its cost. Confidence high. ### Brand spec sheets (what fields brands publish and in what order) **Anker Prime Power Bank (26K, 300W)**, Macworld review https://www.macworld.com/article/2958027/anker-prime-26k-power-bank-300w-review-slim-macbook-power-bank.html - verbatim: "26,250mAh" and "99.75Wh"; "2x USB-C (140W PD 3.1); 1x USB-A (22.5W)"; "Total Power Output: 300W"; input "250W"; "Weight: 21.1oz (599g)"; "At 99.75Wh it is within TSA, CAA and EASA airline limits for carry-on"; charged a 14-inch M2 MacBook Pro to 100% with 33% left, "a total recharge score of 123%". - Anker product page https://www.anker.com/products/b110a-anker-prime-26k-300w-power-bank-with-charging-base was blocked for fetching. The per-port figures are instead taken from two read reviews: Basic Tutorials https://basic-tutorials.com/reviews/gadget-reviews/anker-prime-powerbank-26k-300w-review/ (verbatim: "USB-C: 140 watts", "USB-A: 22.5 watts", "300 watts", "26,250 mAh", "99.75 Wh", input "up to 250 watts", "approximately 600 grams") and WattBench https://wattbench.eu/reviews/anker-prime-powerbank-26k-300w.html (verbatim: "140W single-port output", "300 W", "250 W", "600 g", "Lithium-ion"). The 28 V 5 A per-port line is not cited for this product; it is cited from the UGREEN spec table. - Supports: 99.75 Wh from 26,250 mAh means a 3.8 V nominal; the title wattage (300 W) is the sum of ports; per-port maximum 140 W. Confidence high. **Anker Laptop Power Bank (25K, 165W, built-in retractable cables)** https://www.anker.com/products/a1695-anker-power-bank-25000mah-165w - verbatim: "Total Capacity: 25,000mAh"; USB-C "3-11V⎓3A / 5V⎓3A / 9V⎓3A / 10V⎓2.25A / 12V⎓3A / 15V⎓3A / 20V⎓5A (100W Max)" input and output; "USB-A Output: ... (33W Max)"; "Total Output: 165W Max"; "Weight: 21.0 oz (595 g)". - fetched excerpt: dual USB-C 165 W max; USB-C plus USB-A 133 W max; about 2 hours to recharge with a 100 W or higher charger at 25 °C; "usable output approximately 63-70Wh in practice" of 90 Wh (this line may be the fetch tool's paraphrase of a page footnote; treat as low confidence). - Supports: the "3-11V 3A" line is how PPS appears on a spec sheet; power-split table is a standard spec-sheet element; input wattage and recharge time are published together. Confidence high for verbatim lines. **UGREEN Nexode 25000mAh 200W**, GigaParts spec table https://www.gigaparts.com/ugreen-nexode-power-bank-25000mah-200w-with-smart-digital-display.html - verbatim: "25000mAh(90Wh)"; input per USB-C "20V/3.25A 65W Max"; output C1 "28V/5A 140W Max", C2 "20V/5A 100W Max"; USB-A "5V3A 9V2A 12V1.5A 10V2.25A"; weight "592" g; display "TFT". Recharge time not on the table; the Trusted Reviews summary in search results says about 2.5 hours with a 65 W charger (search excerpt, low confidence). - Supports: 90 Wh from 25,000 mAh means 3.6 V nominal; C1 and C2 differ; USB-A tops out around 22 W; input 65 W is well below output 200 W. Confidence high. ### Phone and laptop side (what the device can take) **Apple, Fast charge your iPhone** https://support.apple.com/en-us/102574 - verbatim: "use a 20W adapter or higher to charge up to 50 percent battery in around 30 minutes."; iPhone 17 Pro models "up to 50 percent battery in around 20 minutes with a 40W adapter or higher." **Wikipedia, iPhone 16 Pro (infobox)** https://en.wikipedia.org/wiki/IPhone_16_Pro - verbatim: "13.94 Wh (3582 mAh) Li-ion @ 3.89 V"; Pro Max "18.17 Wh (4685 mAh)". - Supports: a phone needs 20-40 W, and holds 14-18 Wh, so a 37 Wh bank is roughly two phone charges after losses. Confidence high. **usb-guide.com, Samsung PPS charging guide** https://usb-guide.com/samsung-pps-charging-guide/ - verbatim: "25W charging requires PPS output of 3.3-11V 2.25A"; "45W charging requires 3.3-11V 5A"; "Using a regular 3A cable with a 45W charger will cap your charging speed at 25W." **Samsung UK support, How to use Super fast charging** https://www.samsung.com/uk/support/mobile-devices/how-to-use-super-fast-charging/ - verbatim: "45W TA + 5A cable (E-marked)"; "Super fast charging cannot be performed using standard chargers." **Wikipedia, Samsung Galaxy S25** https://en.wikipedia.org/wiki/Samsung_Galaxy_S25 - verbatim: S25 "Super fast charging at 25W"; S25+ and Ultra "Super fast charging 2.0 at 45W"; Ultra "Li-ion 5000 mAh". - Supports: Samsung's fast charging is PPS plus a 5 A cable; without PPS a Galaxy charges slowly even from a high-watt port. Confidence high that PPS is required (usb-guide plus the Anker spec line "3-11V⎓3A" under PPS), medium that Samsung's own page names PPS (it names the 45 W adapter and e-marked cable instead). **Granite River Labs, Introduction to PD 3.1** https://www.graniteriverlabs.com/en-us/technical-blog/usb-power-delivery-specification-3-1 - verbatim: "EPR cables must contain an E-Marker"; "The E-Marker must be set to EPR Mode Capable and provide notification that it supports 50V and 5A." **Wikipedia, USB-C** https://en.wikipedia.org/wiki/USB-C - verbatim: "Every USB‑C cable must support at least three amps of current and up to 20 volts for up to 60 watts"; "All Type‑C cables except the minimal combination of USB 2.0 and only 3 A must contain E-marker chips". - Supports: above 60 W the cable is the part that has to match. Confidence high. ### Wireless **Wikipedia, Wireless Power Consortium** https://en.wikipedia.org/wiki/Wireless_Power_Consortium - verbatim: "Qi2 delivered up to 15W of charging power and provided magnetic attachment"; "Qi2 25W delivers up to 25W of charging power, nearly 70% more power than the original Qi v2.0." **Anker, Qi2 explained** https://www.anker.com/qi2-wireless-charging - verbatim: "offering up to 15W charging speeds"; "Qi2 incorporates features inspired by Apple's MagSafe technology, notably the Magnetic Power Profile (MPP)." **audioXpress, Industry begins Qi 2.2 deployment** https://audioxpress.com/news/industry-begins-qi-2-2-wireless-charging-deployment - verbatim: "Introducing support for up to 25 watt power transfer" (the article adds up to 50 W, device-dependent); "Announced and available to members of the Wireless Power Consortium since April 2025"; "Chinese companies such as Baseus are among the first brands to deliver Qi2.2-certified power banks, with three new models rolling out globally starting in August 2025."; UGREEN's MagFlow described as "launching in Q3 2025". **powerbanks.fyi glossary, Qi2** https://powerbanks.fyi/glossary/qi2 - verbatim: "Qi2 is the magnetic Qi wireless charging standard. Original Qi2 supports 15W."; "For power banks, it usually means a magnetic phone pack with certified Qi wireless charging behavior." - Supports: two certified tiers (15 W, 25 W since mid-2025); "MagSafe compatible" without Qi2 means magnets but no certification. Confidence high. ### Capacity arithmetic and losses **Anker support, Why is the rated capacity lower than expected** https://support.anker.com/s/article/Why-is-the-Rated-Capacity-of-Power-Banks-Lower-Than-Expected - Read directly at the redirect URL https://service.anker.com/article-description/Why-Is-the-Rated-Capacity-Marked-on-a-Power-Bank-Lower-Than-Expected after the blind check. verbatim: "10Ah × 3.7V = 37Wh"; "37Wh / 5V = 7.4Ah = 7,400mAh"; "typically around 82% efficiency"; "Rated Capacity = 7,400mAh × 0.82 = 6,068mAh". **Anker UK blog, How to check capacity of a power bank** https://www.anker.com/uk/blogs/power-banks/how-to-check-capacity-of-power-bank - verbatim: "A 10,000 mAh power bank stores around 37 Wh of energy. After conversion losses, it typically provides around 30 to 35 Wh of usable energy, which is roughly equivalent to 6,000 to 7,000 mAh at a 5 V output."; "Expect roughly 60% to 75% of the rated mAh as usable output". **Power Bank Expert, real vs rated capacity** https://www.powerbankexpert.com/real-battery-capacity/ - verbatim: "5V capacity = (3.7V * Advertised Capacity) / 5V"; "only 68.82% of the advertised capacity can be supplied to devices" (before converter losses); efficiency "generally between 80% and 90%"; one study found gaps "as much as 40%". - Supports: the mAh-at-5-V figure is about 60% of the headline, the Wh-at-port figure is about 80-90% of stored Wh, and both are physics rather than fraud. Confidence high (three independent worked examples agree: Anker 61%, UGREEN PB726 58%, Xiaomi 60%). ### Low-current mode **Anker support, What is Trickle Charging Mode** https://service.anker.com/article-description/What-is-Trickle-Charging-Mode - verbatim: "designed for low-power consumption devices, such as earbuds, Bluetooth earphones, and smart wearable rings"; "The battery requires connected devices to draw at least 30 – 90mA to continue operation."; "Double-press the power button to toggle"; "automatically turns off after 2 hours". **ChargeKeku, power bank turns off with earbuds** https://www.chargekeku.com/blog/power-bank-turns-off-charging-earbuds/ - verbatim: "the charging case draws less current than the power bank expects to see"; "This mechanism is product-specific. It should not be converted into a universal shutdown-current number." - Disagreement kept: Anker gives 30-90 mA for its own banks; ChargeKeku says there is no universal number. We cite Anker's figure as Anker's, not as a category constant. ### Pass-through **Anker blog, pass-through charging** https://www.anker.com/blogs/power-banks/pass-through-charging-power-bank - verbatim: "it refills its own cells from the wall while feeding a phone, tablet, or pair of earbuds from its output"; "In practice, the device on the output side usually gets priority."; "Not inherently, though it does add heat, and heat is what ages lithium cells." - Plus the ChargerLAB test page above. Confidence high. ### Retail listings (what data is already present) **Amazon, Anker Prime 26K 300W (B0F66LNB8D)** https://www.amazon.com/dp/B0F66LNB8D - verbatim title: "Anker Prime Power Bank, 26,250mAh 300W Fast Charging | 3-Port Portable Charger, Two-Way Charging, TSA-Approved, App Control, for MacBook, iPhone 17 / 16 Series (Base Not Included)". The product-information table did not render for the fetch tool. **Amazon, UGREEN Nexode 25000mAh 200W (B0CXHM5RY2)** https://www.amazon.com/dp/B0CXHM5RY2 - verbatim title: "UGREEN Nexode 25000mAh 200W PD 3.1 TFT 3-Port Power Bank | TFT smart display, 90Wh, PD 3.1 fast for laptops". Table did not render. - What this tells the scraper: titles reliably carry mAh, total W, port count, and often Wh, "TSA-approved", "two-way" (pass-through) and "built-in cable". Per-port wattage, PPS, rated capacity, cell format and efficiency are not in titles; per-port tables and PPS lines are on brand pages. Walmart, Newegg, B&H and Best Buy all blocked the fetch, so the Amazon "Product information" rows (battery cell composition, wattage, item weight) are assumed from the title plus brand pages and marked medium confidence in the facet hints. ### Primer on the airline line **Anker blog, Can you bring a portable charger on a plane** https://www.anker.com/blogs/power-banks/electronics-on-the-go-can-you-bring-a-portable-charger-on-a-plane - verbatim: "Watt-hours (Wh) = (Voltage (V) × mAh) / 1000"; fetched excerpt: about 27,000 mAh at 3.7 V is about 100 Wh; "up to 2 larger batteries (101-160 Wh)" with approval. - Supports: why so many flagship banks are 26,000-27,000 mAh. Confidence high (arithmetic checks: 27,000 × 3.7 / 1000 = 99.9). ### Could not reach - r/UsbCHardware wiki (reddit.com blocked for the fetch tool). The enthusiast-community slot is filled by ChargerLAB (which measures) and powerbanks.fyi (hobbyist glossary); this is a gap worth noting. - FAA PackSafe (403). Replaced by 49 CFR 175.10, which it summarises. - Wirecutter / Tom's Guide / TechRadar methodology pages (truncated or 403). The Tom's Guide "power-to-weight ratio" idea appears only as a search excerpt and is not cited. ## Data points used for derived metrics | Bank | mAh | Wh | nominal V implied | weight g | Wh per 100 g | input W | stated recharge | |---|---|---|---|---|---|---|---| | Anker Prime 26K 300W | 26,250 | 99.75 | 3.80 | 599 | 16.7 | 250 (dual) | not stated | | Anker 25K 165W | 25,000 | 90 | 3.60 | 595 | 15.1 | 100 | ~2 h | | UGREEN Nexode 25000 200W | 25,000 | 90 | 3.60 | 592 | 15.2 | 65 | not sourced (Trusted Reviews unreachable) | | UGREEN PB726 20000 165W | 20,000 | 72 | 3.60 | 534 | 13.5 | n/a | n/a | | Baseus 140W 2C1A | 24,000 | 86.4 | 3.60 | n/a | n/a | 140 | 1 h 06 | | CUKTECH PB100 10000 30W | 10,000 | 36.5 | 3.65 | 196 | 18.6 | n/a | n/a | | Xiaomi magnetic 5000 | 5,000 | 19.35 | 3.87 | 122 | 15.9 | n/a | n/a | | Anker Nano magnetic 10000 (A110Z) | 10,000 | 39.1 | 3.91 | 239 | 16.4 | n/a | n/a | | Xiaomi magnetic 10000 (WPB1007ZX) | 10,000 | 39.1 | 3.91 | 226 | 17.3 | n/a | n/a | | AOHi Starship 40000 | 40,000 | 146 | 3.65 | 916 | 15.9 | 140 | n/a | Recharge-time fit: hours ÷ (Wh ÷ input W) = 1.78 (Baseus) and 2.2 (Anker 25K). The UGREEN 2.5 h point was a Trusted Reviews search excerpt; the page returned HTTP 530 on two attempts and the point is dropped. A rule of "about 2 × Wh ÷ input W" misses the two sourced points by 10% and 12%, so it is stated as plus or minus 15% with confidence low. ## Against the existing add-on schema Add-on read: `machines/electronics/add-ons/charger.jsonc` (charger_type, output_wattage, port_types, fast_charge_standards, power_bank_capacity_mah, power_bank_capacity_wh, device_compatibility_raw) composed with electronics-standard (connectivity, power.wattage, power.battery_capacity_mah, compatibility) and machines-standard (sizing.weight, dimensions, high_signal_markdown). | Facet in this doc | In add-on today | Proposed kind under AGENTS.md | Note | |---|---|---|---| | energy_wh | yes, `power_bank_capacity_wh` | quality currency | The comparable number. Dense enough to commit to augmenting from mAh × stated V, or from the label photo (Wh is legally printed). | | cell_capacity_mah | yes, `power_bank_capacity_mah` (and duplicated as `power.battery_capacity_mah` in electronics-standard) | quality currency, but secondary | Keep one of the two fields, not both. | | max_single_port_output_w | no; `output_wattage` is ambiguous between total and per-port | hard filter | Proposal: split `output_wattage` into `max_single_port_output_w` and `total_output_w`. Buyers filter on what one device can draw. Source is brand spec tables, not marketplace titles, so marked researched with low backfill cost. | | total_output_w | partly, `output_wattage` | annotation only | The title number. Keep as the raw field if one must go. | | wireless_magnetic | partly: `port_types: wireless_coil`, `fast_charge_standards: magsafe` | hard filter | Proposal: an enum `wireless_tier` [none, magnetic_uncertified, qi2_15w, qi2_25w]. The two certified tiers are a text fact, not a photo fact. | | pps_support | yes, `fast_charge_standards: pps` | hard filter | Already there. The spec-sheet tell is a "3.3-11V" or "3-11V" output line on the brand page; absent from titles, so marked researched with low backfill cost. | | recharge_input_w | no | quality currency | Published on every brand page as "Input: NN W Max", not in marketplace titles; marked researched with low backfill cost. Drives recharge time. | | pass_through | no | hard filter (boolean) | Titles say "two-way charging". Cheap to extract. | | low_current_mode | no | high_signal_markdown | Sometimes in bullets, reliably only in manuals; marked researched. Worth a sentence, not a column. | | integrated_cable | no | hard filter (enum) | Titles say "built-in cable" / "retractable". A photo also shows it, so this is borderline; the retractable-versus-fixed distinction is text. | | rated_capacity_mah | no | high_signal_markdown | Printed on the unit, rarely on the listing. Backfill from label photos for the top N only. | | conversion_efficiency_pct | no | researched, outside schema | Only ChargerLAB-style tests produce it. Top N via their reviews. | | airline_band | no (derived) | derived from energy_wh at query time | Not a stored field. | | safety_certification | no, and AGENTS.md cuts certifications | high_signal_markdown | 3C decides flying within China; UL 2056 is the only US safety signal. Seldom on Western listings, so marked researched. Belongs in the markdown line, not a column. | | cell_format | no | high_signal_markdown | Teardown-only for most products; Amazon's "battery cell composition" row is unverifiable. | Add-on fields this doc considers noise for power banks: `device_compatibility_raw` (every bank claims every phone; the useful compat facts are PPS and Qi2, both already enums); `power.battery_life_hours` from electronics-standard (meaningless for a bank). `release_year` is fine as recency. ## Branches (2026-10-19) Each branch is a claim about how an expert narrows the choice, and each names the sentence in the register or in these notes it follows from. The `when` labels on the two numeric splits are the answers their questions offer; the third split's labels are its values list. **Split 1, max_single_port_output_w ("Charging a phone, a tablet or handheld, or a laptop?")** - when `laptop`: then_ask integrated_cable, total_output_w, recharge_input_w; makes_irrelevant wireless_magnetic. - integrated_cable: "on laptop bricks it is rated for the bank's own wattage, which a random cable above 60 W may not be" (integrated_cable, why experts care). - total_output_w: "Read it with the per-port maximum and the split table, never alone" (total_output_w, why experts care) and "The split table is worth backfilling for the top N laptop bricks" (its backfill note). - recharge_input_w: "The bricks that accept 140 W or more need a laptop-class charger to do so" (recharge_input_w, why experts care). - wireless_magnetic irrelevant: "a laptop wants 60 to 140 W" (max_single_port_output_w, why experts care) against "Magnetic packs carry one or two soft-pack cells, 19 to 39 Wh, at 15 W wireless on most certified units" (trade-off) and the family line "iPhone 12 or later and Qi2 Android phones". - when `phone`: then_ask pps_support. - "Without PPS a Galaxy charges slowly even from a 100 W port. iPhones do not need it." (pps_support, why experts care). - No branch for `tablet or handheld`: the register only places them "between" (split 1 rationale), which changes nothing downstream. **Split 2, energy_wh ("Pocket top-up, a day or two for your phone, or laptop-sized reserve?")** - when `laptop-sized reserve`: then_ask airline_band; makes_irrelevant wireless_magnetic. - airline_band: "the 100 Wh line decides whether the bank boards a plane without approval, which is why so many flagship banks are 26,000 to 27,000 mAh and 90 to 99.75 Wh" (energy_wh, why experts care); "laptop bricks 72 to 100 Wh. Above 100 Wh is rare and travel-hostile" (energy_wh, typical range). - wireless_magnetic irrelevant: "these packs hold 19 to 39 Wh" (wireless_magnetic, why experts care), so none reach the 70 to 100 Wh band. - when `pocket top-up` or `a day or two for your phone`: makes_irrelevant airline_band. - "Up to 100 Wh flies in carry-on with no approval" (airline_band, why experts care) and "Magnetic packs 19 to 39 Wh, pocket packs 36 to 39 Wh" (energy_wh, typical range): every bank in these bands is in the no-approval band, so the question cannot narrow the set. **Split 3, wireless_magnetic ("Snaps onto your phone with no cable, or wired?")** - when `magnetic but uncertified`, `Qi2 15 W` or `Qi2 25 W`: then_ask safety_certification; makes_irrelevant cell_format. - safety_certification: "The aviation regulator flags wireless banks: easy to counterfeit, often no UN 38.3 evidence, passenger reports of thermal runaway" (wireless_magnetic, why experts care; IATA operators guidance, verbatim above). - cell_format irrelevant: "Infer soft-pack for magnetic packs, since both teardowns that name the format found ATL soft-pack cells" (cell_format, backfill note): the value is fixed on this branch. - No branch for `none`: the rationale says a no "leaves the wired packs", which filters on the split itself and changes nothing downstream. Renderer note: the flowchart form draws an "otherwise" edge only when the split facet has a values list. The two numeric splits have none, so the `tablet or handheld` answer has no drawn edge from question 1 in the flowchart; the timeline (default) and mindmap forms are unaffected. The scripts are out of scope for this pass, so this is recorded rather than fixed. ## Trimmed detail (2026-10-19) Sentences cut from capped fields that carried a fact, a number or a source. No claim was dropped from the register; each is either kept elsewhere in the JSON (noted) or lives only here. - **summary**: "and less to reach a phone" (less than the 80 to 90 percent reaches a phone, because efficiency is lowest at 5 V; kept in conversion_efficiency_pct). "In the Zamana taxonomy these sit under the charger leaf as charger_type power_bank." (kept in the scope line at the top of these notes). - **mechanism.plain**: "USB Power Delivery (PD), the USB-C charging protocol" (gloss; in vocabulary). "on the units measured", qualifying the 10 to 21 percent loss (ChargerLAB Baseus 140W and AOHi 40000). "so a 90 Wh bank delivers roughly 72 to 80 Wh to a laptop and a smaller share to a phone." "Output wattage is set by the circuit and by what the device can take". "the newer PD 3.1 mode" and "a cable whose chip declares it can carry 5 A (an e-marked cable)" (glosses; in vocabulary). "Magnetic banks add a coil that charges a phone through its back using Qi2, the magnetic wireless standard" (gloss; in vocabulary). "the aviation regulator flags these packs because they are easy to counterfeit, often lack evidence of the UN 38.3 transport test, and passengers have reported them overheating" (IATA operators 2026; kept in wireless_magnetic and in that reference's supports). - **splits[0].rationale**: "which is most of the catalog either way" (laptop bricks and pocket packs together are most of the catalog). - **splits[1].rationale** and **splits[2].rationale**: wording only; no fact cut. - **max_single_port_output_w.why_experts_care**: wording only; no fact cut. - **energy_wh.why_experts_care**: "and about 60 percent of the advertised mAh to reach a phone at 5 V" (kept in rated_capacity_mah, the Rated capacity vocabulary entry and judgement 2). - **wireless_magnetic.why_experts_care**: "so its wireless rate is whatever the brand chose" (uncertified packs). IATA's phrase "as an emerging concern" (kept in the reference's supports). "going into thermal runaway" shortened to "thermal runaway". - **airline_band.why_experts_care**: the gloss "(China's compulsory certification)" on the 3C mark (in vocabulary). "may carry two" restated as "two at most". - **conversion_efficiency_pct.why_experts_care**: "and a 146 Wh bank peaked at 83 percent at 100 W" (ChargerLAB AOHi Starship 40000; kept in that reference's supports and in deliverable_wh). - **cell_format.why_experts_care**: "(four SunPower cells in one UGREEN, two EVE cells in a CUKTECH pocket pack)" (ChargerLAB PB726 and PB100 teardowns; kept in those references' supports). Note the CUKTECH is a pocket pack, so 21700 cylinders appear in pocket packs too, not only laptop bricks. - **judgements[1].claim**: "at the port" and "rather than mislabelling" (the gaps are not fraud; Power Bank Expert and the Anker worked examples). - **judgements[2].claim**, **judgements[5].claim**, **judgements[9].claim**: wording only; no fact cut. - **iata_operators_2026.supports[2]** and **anker_uk_capacity_blog.supports[0]**: wording only; no fact cut. ## Corrections after the blind check (2026-10-19) 1. Efficiency range narrowed to the measured 79 to 90 percent; mechanism loss restated as 10 to 21 percent; 'rises with voltage' replaced with lowest at 5 V, highest at 28 V, not in strict order between (12 V at 82.4% sits below 9 V at 84.5%). 2. UGREEN 2.5 h recharge point dropped (Trusted Reviews unreachable). Refill rule restated as 2x plus or minus 15 percent, confidence low, two points. 3. Anker support worked example now read directly (verbatim above). Anker Prime per-port figures now cited from Basic Tutorials and WattBench, both read; the search-excerpt reference was removed. 4. Magnetic-pack cell claim now rests on the Anker Nano A110Z and Xiaomi WPB1007ZX teardowns (soft-pack, 10,000 mAh); the Xiaomi 5,000 mAh unit is described only as single-cell. 5. 12 V added to the PD fixed voltages. 6. IATA's reason for flagging wireless banks corrected to counterfeiting, missing UN 38.3 evidence and passenger-reported thermal runaway; the coil-heat claim was dropped, not re-sourced. 7. audioXpress entry now records the up-to-50 W device-dependent clause and UGREEN MagFlow as Q3 2025. 8. low_current_mode, pps_support, safety_certification, max_single_port_output_w and recharge_input_w reclassified as researched, with where each sits on a brand page in the hint. 9. Split 1 reworded to 'What will this bank need to refill when you are away from a plug'. ## Corrections (2026-10-19, second pass: branches, questions, caps) 1. Branches added: 5 (split 1: laptop, phone; split 2: laptop-sized reserve, pocket top-up / a day or two for your phone; split 3: the three magnetic answers). Each is traced to a register sentence under "Branches" above. 2. Questions rewritten: 3 split questions and 8 facet cold-start questions (the three split facets, pps_support, integrated_cable, pass_through, low_current_mode, cell_capacity_mah). airline_band's "Will you fly with it?" already fit and is unchanged. Each split question now matches its facet's cold-start question. Split 1 moves from "What will this bank need to refill when you are away from a plug: ..." (item 9 above) to "Charging a phone, a tablet or handheld, or a laptop?". 3. Fields trimmed to cap: 17 (summary, mechanism, 3 split rationales, 6 why_experts_care, 4 judgement claims, 2 reference support lines). Cut facts are under "Trimmed detail (2026-10-19)". 4. Validator clean. category.md and viewer.html regenerated. generated_at, facet ids, priorities, evidence ids and reference ids unchanged.