Hi, just wanted to share some good news. The high-standby-power issue has been fixed on the current ASP electronics kits. I'm calling it a "SaberCore 2.1" driver because it fixed the biggest and most common issue people have been reporting about the SaberCore 2.0 boards.
The short version is: Standby power has been reduced from 200+ mA to about 4.5 mA. This means it'll now take about a month to drain a cell instead of a day, and there should be no more heat-related issues.
Here the new board's power graph with a 3.64V NCR18650B cell. I was too impatient to charge the battery before testing, but the blade-on power would be much higher with a full cell:
It's now going into sleep mode immediately after the sound and/or blade stops, and it idles at an average of about 4.5mA. So, with an updated driver board it's now safe to leave the battery in while the saber isn't being used, but you should still remove the battery if the saber will be unused for more than a couple weeks.
For reference, here is how the older version behaved. The important part is that the old board never went below 200mA, which is the issue that is now fixed on current drivers. Also, the battery here was at 4.06V (if I recall correctly), so the blade-on power is higher.
This is a pretty major upgrade, especially for ASP owners who have no charge port.