What's with the expansion cards and battery impact?

I’ve been hearing a couple of things about the expansion card I wish it could be clarified or with the newest software and hardware updates.
-The expansion cards drain the battery (as expected) but even not during usage or sleep (reddit post on live testing on HDMI expansion card).

  • USB-C and USB-A expansion cards are more complicated than just ports and (see above) drain power when not used?
  • Are storage card expansion cards like thumb drives (USB flash drives) in the system or like hard drives?
  • What would be the preferred choice between a larger NVMe storage (say 1TB) or a smaller NVMe storage (say 250GB) with a 1TB storage drive?

I don’t particularly mind the battery issue, my current laptop is such a power drain and I’ve used it for so long I’m used to getting glued to a power outlet. But since there’s no “empty” expansion cards yet, as some have requested, I’m either going to run 4 cards at the same time or walk around “naked”.

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  • USB-C are pass-through so should not be draining any extra power.
  • USB-A keeps some subsystems on the mainboard powered on so it does contribute to some extra drain. (source)
  • The storage expansion cards use NAND flash so they are more like really fast flash drives.
  • Don’t know of any measurements off-hand, but I would assume the storage card consumes more power than the internal NVMe drive.

For a general idea of total impact on battery life the cards have, my setup (1C, 2A, 1HDMI) drains at 1.2 Wh higher during standby than with just 1C, which is about 2% battery drain per hour.


I see, thank you.

Honestly, I’m looking forward to “empty” expansion cards or an update to expansion cards that doesn’t drain power when not used. I actually rarely use ports other than USB-A for the occasional flash-drive transfer.


Is there really no way to completely disable an expansion card while not in use? If we could keep it active (so that it drains power) only when in use it would basically fix the issue for most of us.

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That would be the preferred option, but apparently it’s not out yet?

Just to say I have a 256GB expansion card permanently fitted and I can leave the laptop off or in hibernate and the battery records no loss overnight

Check out the Snack Drawer. My laptop usually runs one USB-C in the back slot on each side and one Snack Drawer in the front spot.


I made detailed tests for this, you might like to read the results in:

USB-C cards use no power on suspend. USB-A do use power, and a surprising lot (300-500mW).

I’m not sure I understand that question. The SSD expansion card is a SSD drive that connects over USB-C, so it’s more like a USB flash drive than a “real hard drive”, which would connect over SATA, SAS, or NVMe. That said, it should still be pretty fast. This might be worth discussing in a separate topic. See also:

It really depends on your use case. I picked the former; I already had my system on a 1TB NVMe card, and there was no way I was going back to smaller on that, for sure.

One key thing to keep in mind is that any expansion card plugged into your laptop will take power, at runtime or suspend (except the USB-C cards). So if you rely on the SSD expansion card, you will take a 250mW drain on suspend (10→5 days suspend, half!) and close to 2W at runtime (also doubling power usage).

So if you can afford the expense on the NVMe disk, do it.

Some people have actually ordered 4 USB-C cards exactly for that reason: