I haven't flown my Mini for about a year. I'm now charging the batteries in the drone. They don't get beyond two lights after a long time on charge. I believe they were left discharged from flight the last time which is similar to what I do for Lipo batteries I use in my electric RC cars. How long should I expect them to take to get beyond two charging lights?

Try cycling them, meaning discharging them by flying the drone (keep it close by, it's not the time to set any new records...) and then recharging them while keeping them under close observation, just to be safe. If they don't go past 2 bars, I'm afraid but they are likely gone.
As for LiPos, in theory you should not leave them fully discharged for long periods of time... the optimal voltage for long-term storage is 3.8V per cell, and most modern chargers have a Storage mode that does exactly that. Truth to be told, if you don't squeeze every amp out of them, you will see that once they cool down their resting voltage is probably in the 3.6-3.7V, which for all practical purposes is good enough for storage.

120ccpm Posted at 5-31 17:20
Try cycling them, meaning discharging them by flying the drone (keep it close by, it's not the time to set any new records...) and then recharging them while keeping them under close observation, just to be safe. If they don't go past 2 bars, I'm afraid but they are likely gone.
As for LiPos, in theory you should not leave them fully discharged for long periods of time... the optimal voltage for long-term storage is 3.8V per cell, and most modern chargers have a Storage mode that does exactly that. Truth to be told, if you don't squeeze every amp out of them but keep a safety margin, you will see that once they cool down they recover to a resting voltage that is not far from 3.8V, and for all practical purposes good enough.

Thanks. It looks like I just didn’t give it enough time. First one fully charged  2nd on the way.

Make sure to use a charger (and cable) that supports Quick Charge (QC), as it significantly improves your charge time. The lights on the Mini will tell you if it's fast-charging: if your charger supports QC, you will see the lights blinking slowly for a couple seconds (while the Mini negotiates the charge rate), then going much faster.

Hello there rramjet. I am to read and to know that you are having this issue with your DJI Mavic Mini's intelligent flight batteries. and thank you for giving out this update as well that the first DJI intelligent flight battery is fully charged and the 2nd DJI intelligent flight battery is now charging. Just a reminder that the DJI Mavic Mini Charger needs to have an Input of 100-240 V, 50/60 Hz, 0.5A , an Output of 12V 1.5 A / 9V 2A / 5V 3A and a Rated Power 18 W. Thank you.