The Lenovo ThinkPad E585 is a part of the ThinkPad E Series which is a notebook computer series introduced in 2010 by Lenovo. It is marketed to small and medium-sized businesses.
My E585 wasn't turning on at all. I swapped out the battery, and now it turns on, but the new battery is at 7% (and dropping) and I can't get it to charge further, whether the laptop is on or off. Have confirmed that it won't charge even with a known-good power outlet; I also tried it with the USB-C charger that works for my partner's laptop, and that didn't help (though that could just be incompatibility). How can I figure out what the obstacle to the battery charging is? The only other thing I can think of would be replacing the charger, but I am not optimistic that will work.
When you said that you tried a "....known-good power outlet;..." did you mean a different, known working compatible power adapter for the laptop or an AC wall power outlet that the adapter is connected to?
If you haven't tried a different known working, compatible adapter i.e. 65W USB-C, try connecting your power adapter to a mobile phone that has a USB-C charge port and check if it starts to charge.
The beauty of using USB-C is that it should work when connected to any device which has a USB-C port. In this case, the wattage output rating of the USB-C adapter doesn't matter because it is the connected device that signals the adapter what it needs and not that the adapter supplies the maximum voltage/current that it is capable of supplying regardless e.g. a lot of phones only require 5V DC @ 2A i.e. 10W or even 9V @ 1.6A i.e.~15W or 5A (45W). It depends on the Wattage (W) rating of the charger what it can supply, so a 65W rating adapter would have no trouble supplying the lesser voltages/currents
If the adapter is OK and if the laptop's USB-C charge port is visually OK i.e. no bent pins or other damage/blockage in the enclosure etc, then you may need the schematics for the motherboard to find out what and where the problem is. (I couldn't find a free download, this is the cheapest that I could find - search for NM-B421 schematic as you may have better luck finding a free download)
Here's the boardview file that shows the location and ID of all of the components on the motherboard. You will need to zoom in a lot to be able to view the component details.
Having both files i.e. schematics + boardview, makes it easier to find components in the charge path as shown by the schematics
Here's the hardware maintenance manual that may also help if you need to disassemble the laptop further for any reason e.g. view the underside of the motherboard perhaps.
Looks like it's fault finding at board level on the motherboard.
You may have to get the schematics to do that or if you're lucky there may be something visibly obviously damaged seen on the motherboard when you open the laptop to start checking what's wrong
11 
417 
1.6k 
Hey there OP, if you look inside the port can you see any debris or dust? You could try to clean the port and see if that fixes the issue.
by Jacob Mehnert
Hi @lukes56417
Is the laptop's power status indicator LED on or off when the charger is connected to the laptop?
by jayeff
The power indicator is off.
by Luke S