That beats me. My gen3 Prius has just sat for 3 weeks while I had an operation and recovery. Started first time.
I once left my Gen II parked for three months without starting. When I finally did start it, it was no problem and it started right away.
Jeanne, my car was in the body shop getting hail damage fixed for 7 weeks. It had no problems starting. I specifically asked if they had to jump it. The battery was in good shape since I was not doing a lot of short in town trips just prior to going in the shop.
Oh wow, dig out an old post buried somewhere in time! Anyways, if you 2010 Prius still has the original battery then yeah, you need to have it replace. I will also charm in my 2 cents here. I went on vacation in 2015 when my Prius was 14 months old and it sat for 3 weeks. Came back and it started right up. But if I have to leave it for 6 weeks then I would probably ask a friend to drive it for me once a week or something.
I keep a battery jump pack (antigravity XP-10) under the front seat to jump the car if the battery is dead.
agree with the above. it's not the 6 weeks, it's the 2010 battery. i'll be going back to my 2012 after 5 weeks, and expect it to start right up. watch me jinx myself.