How We Measure Battery Life, and Why Manufacturer Figures Differ (Steam Deck OLED)
How We Measure Battery Life, and Why Manufacturer Figures Differ explained, with the Steam Deck OLED's own measured figures as the worked example: quoted battery figures are produced under conditions...
Tom Halvorsen
In brief
Steam Deck OLED, battery 50Wh — How We Measure Battery Life, and Why Manufacturer Figures Differ. Measured on hardware rather than argued from theory, on a device we rate for steamOS is the only handheld software that does not feel like a desktop in disguise.
Quoted battery figures are produced under conditions almost nobody replicates. Ours use a fixed brightness and a scripted workload so numbers stay comparable.
Why this matters: Battery is consistently the specification buyers care about most and the one most loosely reported.
What is going on underneath
We set the display to a measured 200 nits rather than a percentage, disable adaptive features that vary between devices, and run the same mix of browsing, video and standby. The result is not the best number a device can produce — it is the number you can expect.
What it looks like in practice
Take the Steam Deck OLED as a worked example. Suspend and resume worked on every one of the 40 titles we tried. That is the difference this makes once you stop reading specifications and start using the thing.
| Specification | Steam Deck OLED |
|---|---|
| Display | 7.4in OLED, 90Hz, 1000 nits HDR |
| Chip | Custom AMD Zen 2 / RDNA 2 |
| RAM | 16GB LPDDR5 |
| Storage | 512GB NVMe |
| Weight | 640g |
| Battery | 50Wh |
| Play time | 3h 40m in demanding titles |
How it varies across the category
One worked example is an anecdote. Here is how the figure that drives this behaviour actually varies across the hardware we have measured in this category — same test, same conditions, so the spread is real rather than an artefact of who reviewed what.
| Model | Display | Price | Our score |
|---|---|---|---|
| Steam Deck OLED | 7.4in OLED, 90Hz, 1000 nits HDR | £479 | 5 / 5 |
| ROG Ally X | 7in IPS, 120Hz, 500 nits | £799 | 4 / 5 |
| Switch OLED | 7in OLED, 60Hz, 400 nits | £309 | 4 / 5 |
| PlayStation 5 Slim | — | £479 | 4 / 5 |
Where the line sits
It helps to have a number in mind before you start comparing. Across the gaming Hardware we have measured, the useful thresholds are the ones where a difference stops being visible: below them you notice, above them you are paying for a specification rather than an experience. The Steam Deck OLED reports 7.4in OLED, 90Hz, 1000 nits HDR for display, which sits comfortably on the right side of that line, and Custom AMD Zen 2 / RDNA 2 for chip. Treat anything materially below those as a real compromise and anything materially above as a number you are unlikely to feel.
Myths worth dropping
- A larger battery always means longer life, when efficiency varies enormously
- Fast charging damages a battery meaningfully in normal use
- Closing background apps extends runtime
Checking it yourself
- Reproduce the conditions rather than trusting a one-off reading — run the same task three times and take the average.
- Note the figure your device reports and the figure it actually achieves; on the Steam Deck OLED those diverge under sustained load.
- Change one variable at a time. Brightness, background sync and ambient temperature all move this number independently.
- Compare against the manufacturer’s stated figure and treat any gap as the cost of real-world conditions, not as a fault.
- Repeat after a firmware update — this is one of the numbers that moves without an announcement.
What to do with this
Compare figures from one source measured the same way, and ignore cross-site comparisons of quoted numbers.
A battery figure is only meaningful alongside the method that produced it.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the gaming we have covered, the category archive lists every review in date order. The closest comparisons we have published are How We Measure Battery Life, and Why Manufacturer Figures Differ (Switch OLED) and How We Measure Battery Life, and Why Manufacturer Figures Differ (Xbox Series S).
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
