"This accessory requires too much power." "Cannot Use Accessory." Plug a portable SSD straight into an iPhone to offload a shoot on location, and a lot of photographers and videographers meet some version of that dialog for the first time — usually mid-shoot, usually with no other drive on hand. The instinct is to blame the cable, the adapter, or the drive itself. Apple's own community forums are full of exactly that troubleshooting spiral: new cable, different port, a factory reset of the drive, before anyone lands on the real answer. It's none of those. The drive is asking the phone's port for more current than it's built to hand out, and iOS refuses the connection outright rather than let the drive brown out — or the phone's battery drain — mid-transfer.
What the error actually means
Apple's own documentation for the iPhone 15 and later states plainly that the USB-C port can charge a small connected accessory "at up to 4.5 watts." That's the ceiling for the whole class of device, SSDs included — it isn't a defect or a setting to raise, it's the maximum the port is designed to source. On the older Lightning connector, the number was smaller still: functionally enough for the connector to negotiate and identify an accessory, not enough to run a spinning or bus-powered drive at all without help. That gap is exactly what one iPhone 13 Pro owner ran into on Apple's own support community after connecting a 1TB SanDisk Extreme SSD through Apple's Lightning to USB 3 Camera Adapter: the phone rejected it outright with "Cannot Use Accessory Extreme 55AE: This accessory requires too much power," and the most direct reply in the thread was blunt — that particular drive, on that particular phone, simply wasn't going to work.
The drive manufacturers say the same thing. Western Digital's own support documentation for this exact error doesn't dispute it or blame the phone — it states the cause outright: "Some external drives need more power than the computer, mobile, TV or media player can give," and points owners toward a powered USB hub or Apple's Camera Adapter with a charging cable attached as the fix. When the drive maker's own troubleshooting page agrees it's a power ceiling, it's not a compatibility bug to wait out in a firmware update.
Not every SSD asks for the same amount
This is also why the complaints aren't universal — plenty of people plug an SSD into an iPhone with no trouble at all. It comes down to how much current that specific drive is built to draw under load, and forum consensus on this has become pretty consistent. SanDisk's Extreme and Extreme Pro portable SSDs are the drives that show up again and again in "requires too much power" threads, widely reported to pull close to 7 watts under a sustained write — comfortably over what the port can supply. Samsung's T7, T7 Shield and T9 lines, by contrast, are the drives most often recommended as the reliable pick specifically because they're built to run on as little as 2.5 watts, well inside the ceiling.
| Typical draw | Under iPhone's 4.5W cap? | |
|---|---|---|
| Samsung T7 / T7 Shield / T9 | As low as ~2.5W | Yes — the most commonly recommended pick |
| SanDisk Extreme / Extreme Pro portable SSD | Reported near 7W under sustained write | No — the drive behind most forum complaints |
| 2.5" HDD in a bus-powered enclosure | 2–5W+, with spin-up spikes higher | Rarely, especially on older Lightning phones |
The usual workarounds — and what they cost you
- A powered USB hub between the drive and the phone supplies the extra current from its own outlet — it works, but a card-sized offload now needs a hub and a hub charger riding along in the bag.
- Apple's Camera Adapter with a charging cable in its second port does the same job with official hardware — at the cost of needing mains power on set just to unload a phone.
- Switching to a lower-draw drive like the Samsung T-series is the most reliable fix of the three, but it doesn't help with a SanDisk or HDD you already own, and it ties your kit to one lineup.
A pass today isn't a guarantee tomorrow. A drive's rated draw is usually measured under light or idle load — a five-second connection test can succeed on a drive that still can't sustain a full 4K or ProRes write once it's actually working. "It connected fine when I tried it" and "it finished the card" are two different claims.
The fix that skips the problem entirely
Every workaround above still puts a power-hungry accessory in the chain between the phone and the port — it just tries to feed it more current. The simpler fix is to not put a bus-powered drive there at all. AirDrop moves files directly between the iPhone and a Mac over Wi-Fi and Bluetooth, drawing nothing from the port a charging accessory would use, so the 4.5-watt ceiling never becomes a factor. No adapter, no hub, no mains power required on location — just the phone and the Mac it was going to end up on anyway.
The catch with a plain AirDrop, as covered in our AirDrop vs Cable vs iCloud comparison, is that sharing straight from the Photos app can silently hand over a re-encoded copy instead of the original, and it dumps everything as a flat batch of files with no folder structure behind it — fine for a handful of vacation photos, not for a day's footage headed into an edit.
That's the gap ShotGrab's iPhone app closes. AirDrop is a real destination in the same wizard used for an SSD, not a share-sheet afterthought — pick your folder structure once, and the app exports each photo and clip's original file, already organized into that structure, into a local folder before handing it to AirDrop in one motion. What lands on the Mac is the original resource, sorted the way you'd sort it by hand, not a flat pile of IMG_1234.MOV waiting to be renamed.
Pair it with ShotGrab on the Mac and both ends of the workflow — card and phone — land footage the same way: verified, organized, and named consistently, without a hub or a charger standing between a shoot and the archive.