Methodology

Last updated: 2026-04-17

ChargingGearLab publishes product reviews that rank chargers, cables, and power banks against a consistent, measurable bar. This page documents that bar. Every review links back here so you know exactly how the numbers were generated — and can decide whether our criteria match your use case.

The bench

Every charger we review is tested on the same rig:

  • USB-PD analyzer: inline USB-C power meter with USB-PD 3.1 + PPS decode, calibrated against a reference load
  • Electronic loads: programmable constant-current sinks rated up to 240W for testing EPR-class chargers
  • Thermal imaging: FLIR ONE Edge Pro — 320×240 resolution, ±3°C accuracy
  • Reference devices: iPhone 15 Pro, iPhone SE, Galaxy S24, Pixel 8, 14" MacBook Pro (M3), 16" MacBook Pro (M3 Max), Steam Deck — representing the wattage curves most readers actually care about
  • Oscilloscope (for cable E-marker analysis and ripple measurement): 100 MHz digital scope with current probe
  • Controlled environment: 22°C ± 1°C ambient, mains voltage logged, results discarded if environmental drift exceeds tolerance

What we measure

Verified wattage (our headline number)

We put each reference device on 5% battery, connect it to the charger under test, and log wattage every second for the first 5 minutes — the window where fast-charge contracts are actually active. The “verified wattage” figure in every review is the peak sustained value observed during that window, rounded to the nearest 0.1W. We ignore the 2-3 second initial spike as it’s not representative of real charging.

This number is measured, not rated. Marketing spec sheets quote the maximum the charger can output under ideal conditions. Our verified wattage is what your phone will actually pull when you plug it in.

Protocol support

We enumerate every protocol the charger announces during the USB-PD handshake. The “protocols supported” list on each review is what the charger actually advertised to our USB-PD analyzer, not what the box claims. Common protocols we verify: USB-PD 3.0, USB-PD 3.1 (EPR up to 240W), PPS (Programmable Power Supply), Qualcomm Quick Charge 4+/5, Samsung Super Fast Charging 2.0 (AFC), OPPO/OnePlus SuperVOOC, Huawei SCP.

Efficiency (η%)

Efficiency is output wattage divided by input wattage (mains-side power meter). We report it at 50% load and 100% load for every charger. A GaN charger should exceed 90% efficiency at rated load; below 85% is a red flag indicating older silicon or poor transformer design.

Thermal performance

We IR-image every charger at 30-minute sustained rated load in a 22°C room. The thermal image published with each review is a single frame taken at the 30-minute mark. The color scale is consistent across every review so thermal figures are directly comparable. We flag any charger exceeding 65°C case temperature as “runs hot” and any exceeding 75°C as unsafe for closed laptop bags / extended desk use.

Real-device runtime

For power banks, we publish minutes-to-80%-charge on each of the reference devices, measured from 5% battery, with the bank itself at 100%. The “usable capacity” figure accounts for the ~10-15% conversion loss inherent to any DC-DC boost circuit — we never quote the battery-cell mAh alone.

Cable testing

USB-C cable reviews include:

  • E-marker chip inspection: we read the cable’s e-marker via a USB-PD analyzer and publish the declared current rating (3A vs 5A), voltage rating, PD version support, and passive vs active designation
  • Continuity & resistance: 4-wire Kelvin measurement on power rails, reported in mΩ per meter
  • Sustained wattage test: charge a 16" MacBook Pro for 30 minutes at 100W+ (or maximum the cable supports), log any thermal throttling or contract renegotiation
  • Ripple measurement: oscilloscope capture of output ripple under load — cheap cables can exceed 200mV peak-peak which stresses device PMICs

How we score (out of 5)

Our 1-5 rating is a weighted combination of:

  • Verified performance (40%): does the product deliver what the box promised — within our measurement tolerance, or not
  • Efficiency & thermals (20%): sustained η% and case temp at rated load
  • Protocol coverage (15%): how many devices does it fast-charge vs alternatives in its tier
  • Build quality (15%): connector pull-force, cable flex, case seams, strain relief
  • Price per watt & value (10%): $/W for chargers, $/mAh for banks, benchmarked against the category median

Scores are internally discussed by at least two editors before publishing. No single editor can unilaterally ship a rating — disagreements above 0.5 points trigger a retest.

Repeat counts & statistical rigor

Every wattage figure is the mean of 3 consecutive 5-minute runs with a 10-minute cooldown between each (the charger’s thermal behavior affects sustained output, so back-to-back runs would bias the result). If any single run deviates more than 5% from the others, we run a fourth and discard the outlier.

Thermal imaging is captured fresh for each run. Protocol decode is deterministic (the charger either supports a protocol or it doesn’t) so we only decode once.

What we don’t do

  • We don’t accept paid reviews. Every product on ChargingGearLab was either purchased by us or sent free for review (disclosed in the review), and payment does not determine coverage.
  • We don’t rank by affiliate commission. Our rating methodology is weighted on measured performance, not on what earns us the most.
  • We don’t test 240W EPR chargers on devices that don’t request EPR — there’s no point, and it would produce misleading low-wattage numbers. If a product is 240W-capable we note it in the review; we measure it at the wattage your actual devices will request.
  • We don’t publish battery-cell mAh as “capacity” — that number is technically true and practically useless.

Retest policy

We retest products at 6 and 12 months. If a firmware update or component revision changes performance (common for GaN chargers and wireless pads) the review is updated with a “Revision notes” section at the bottom. We never quietly change old numbers — every change is stamped and visible.

Errors & corrections

If you believe one of our numbers is wrong, please email hello@charginggearlab.com with the review URL and the specific figure. We take correction requests seriously — especially from manufacturers and fellow testers. All corrections are stamped at the bottom of the affected review.

Open questions?

Questions about methodology, or requests for specific tests we don’t currently perform: hello@charginggearlab.com. We update this page as our test rig evolves.