Ain't that the truth?
GA is spot on, and fast with the good advice.....again. I know it's hard to resist, but I think there's a real advantage to going 'overnight' on the first charge (at least 4 hours after the charge light goes solid). You get the batteries (hopefully) never having been fully charged. That first cycle determines where 'the top' of the charge will be, it will set the usable capacity of the battery and will only degrade from there on. They will never again be as strong as that initial charge.
Ideally the two batteries are balanced, but that can't be exact of course. The Solo uses the total voltage from the two, the weaker one will automatically get worked harder and therefore degrade faster. Every cycle will make the weaker one weaker faster than the stronger one until it can only do a few sessions.
Cutting the routine charges off earlier is not intuitive but does very much increase battery lifetime. Cutting 10% off the charge doubles the number of times you can recharge before replacement. Double. Cut another 10% (20% total, say one session) again doubles it. From say 300 cycles to 1200? Worth considering, unless you're looking forward to buying another battery......
Check out the stuff here around Table 4:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
BTW, this (shutting down 'early') is what's behind the gadget I posted photos of a few posts up. I'm trying to automate that part.......
OF