I like the T480. I have one that I completely refurbished this way, and another one (for work) where I ended up buying and replacing a flaky display cable myself (~$20) even though it was still under warranty because Lenovo's service department couldn't reproduce an intermittent failure and I got tired of shipping it back to them.
Performance is fine, the 1440p display is great, it can idle at 5W, and working on it is easy. The dual-battery system is... weird. I like the concept, but it's been mildly annoying in practice, which I think is why Lenovo ended up dropping it.
This is the last T-series model they made with a hot-swappable battery. There's an internal Li-Po pack and you can choose between another flush-fitting Li-Po or slightly chunkier 6-cell/9-cell cylindrical packs for the external battery.
The charge controller allows you to set charge start/stop thresholds for each battery (e.g. stop charging at 80%, don't top off the cell until it drops below 70%), but it doesn't let you control which battery is discharged first, or when the switchover happens. It always discharges the "healthier" cell first, based on measured capacity / nominal capacity, and it always switches to the other cell at 5% remaining. I think their intent was to allow the two batteries to wear out evenly. But if you want to actually use the full capacity of your cells, you end up putting a lot of stress on the first battery by leaving it at 5% for hours or days. Leave it like this for slightly too long and you'll damage it, and the battery system will start discharging the other battery first, until you damage that one, etc. Hot swapping doesn't work as well as it should, because if the internal battery discharged first, but the switchover was yesterday, it's probably self-discharged to below 5%, and may not be able to provide enough power to survive the hot-swap. It would be nice if you could change the switchover threshold (e.g. to 20%), and nicer still if you could tell it which battery you want it to discharge.
The T490 onwards only have an internal pack. It's connectorized, so you can still buy a fresh one and replace it every few years, but you won't be swapping it on an airplane.
Thanks for sharing. Do you have any resources that I can look at regarding partitioning and structuring data? Right now I'm thinking about using RDS running Postgres.
