BM Cam app for iPhone ssd keeos disconnecting

Been using an external ssd w the Cam app on my iPhone 15 pro, and the app keeps losing the connection w the ssd. My settings are 24-60fps, prores 422, to a Hagibis Magnetic M.2 2230 NVMe SSD Enclosure with Magsafe, with a Kingston 1TB M.2 2230 PCIe Gen 4.0x4 NVMe SSD TLC NAND (R/W Speeds up to 4,540/4,230 MB/s) and it’s connected to my phone via a 20 Gbps usb-c cable. It seems to disconnect after locking my phone to save battery in between shots, but also sometimes while shooting and keeping the app open. Always happens during the most critical moments and I have to unplug and replug the ssd in, and shut and open the BM cam app a bunch of times to fix it. Super annoying. it doesn’t give me any dropped frame alerts while recording and I don’t think it’s the speed of my system that’s bottlenecking. Any help is appreciated.

In almost all cases, this indicates, that the disk (periodically?) draws more power, than the iPhone can deliver. This is a typical behavior, when using NVME based drives, and especially prevalent during (susatained) recording, where power drain may fluctuate the most.

If the drive works on your PC or Mac, when copying large video files to the drive, there is nothing wrong with the drive per se.

If you have access to a powered hub, try connecting the drive to the hub, and the hub to power, before connecting to the iPhone. If that solves the problem, the SSD draws too much power (periodically is the worst, since you get no warning before starting recording).

Standard USB 3.0 max power drain is 0.9A at 5V. That only covers low power drives. That’s the typical limit (give or take) for an iPhone 15 Pro.

NVME drives may start, read and seem to work for a time, but periodically - especially during write - ordinary USB C 3.x (10 GBit) drives (also when connected to USB A) may require up to 1.5A, far exceeding what the iPhone 15 Pro (Max) can deliver reliably.

Note, that external Thunderbolt drives (some also capable of working, when connected to plain USB C) are allowed to draw up to 15W (5V/3A).

And by the way - don’t expect more than 1000 MByte per second at best (down hill, wind from behind) on the USB C connection. Depending on actual drive construction, writing larger values, let’s say 30, 50, 100GByte or more may have a dramatic effect on drive speeds (when the internal “pseudo cache” is full, write speed has to drop; often dramatically, depending on type, capacity, model and manufacturer)

The speeds you quote are purely theoretical values, when mounted internally in a PC socket. At best, depending on interface.

Regards

Current Gen 4 NVMe drives draw more power than an iPhone 15 can deliver. I’ve seen suggestions that a phone can power Gen 4 drives that, like yours, are 22mmx30mm rather than 22mmx80mm, but your experience would appear to justify my skepticism.

I have seen credible claims that an iPhone 15 can provide enough power for at least some Gen 3 NVMe drives.

After looking at this question, I decided to forget about my NVMe drives, which are Gen 4, and instead use Samsung T5 and T7 drives. They work fine.

This gentleman is a bit of a character, but he’s tested both Gen 4 and Gen 3. He was unable to get any Gen 4 NVMe drive to work, but came up with this recommendation if you want to use a Gen 3. He says that it’s faster than a Samsung T7:

Makes sense, thank you so much for the insights!!

I have been having this issue as well and have been using an external power supply. The power bank I use is: INIU Power Bank, 25000mAh 65W USB C Laptop Portable Charger.

I can confirm that the iPhone has trouble powering some SSDs on its own so the power bank is a life saver!

What I also found that worked for me was to make a change in the camera settings. Go to your iOS settings, then select Camera. Then select Formats and change the camera capture from High Efficiency to Most Compatible. While I had initially thought that this setting was for photographs only I figured it couldn't hurt to make the change and to see what happens. So far I have not had any disconnections after making this change while using a power brick and any of my external SSDs with my iPhone 15 Pro Max.