Low main battery charge - when does backup battery jump in?

[will_990]

Hello,
I've read in multiple threads about the fast discharging of the backup battery when the main battery gets low (A05 ROM). Can anyone tell me, at what percentage of the main charge the backup battery starts to drain (below 10% or zero)? I simply don't want to recharge my Axim every day but also don't want to drain the backup battery immediately as happened when I didn't charge the Axim for four weeks.

Any help or link would be welcome
Chris