Question: Some modern laptops ship with an M.2 NVMe interface for an SSD and a SATA interface for an HDD.
Is it ever possible to install an extra battery in the bay of the HDD, so as to have two internal batteries? I’m all for long battery life, and SSDs have become affordable. It’s a pity that a bay remains empty when you don’t need the HDD. It seems like a waste to me, especially when designers work hard to make laptops thinner and thinner.
Answer: Some Dell laptops are designed like this, in particular I’ve noticed this on the XPS 15. Depending on the configuration you get, you may have a smaller battery with an HDD and a small SSD, or a larger battery with no HDD and a larger SSD.
These images are from https://www.dell.com/support/manuals/au/en/aubsdt1/xps-15-9560-laptop/xps-15-9560-servicemanual/procedure?guid=guid-cbca961f-7c16-4c3f-ad46-fa737221ce41&lang=en-us
Some configurations come with the smaller battery and only an SSD, so you end up with an empty space where the HDD would have gone. You can then install an HDD of your choice, or buy an aftermarket replacement battery of the larger size.
Or if you do get a configuration with an HDD, you can take it and the battery out, put in a larger battery, and optionally upgrade the SSD.