Data loss has never been an issue for me. Internal battery protects the ram for quite a while.
And I get about 20 hours of use out of Eneloop batteries. If you're actively using it you just have spare batteries topped up and swap them when the out. If I am not actively using it, it could weeks/months without losing ram contents because the main batteries keep the backup charged. If the backup batery is not good or there is some hardware problem YMMV I think I've only ever lost data because of corruption due to software faults. -- John.
