A group of us are planning a visit to the Allgau in Bavaria in aprill/may. I have a bosch 500 battery and no problems with it. the panned excursion will be rather hilly and we plan about 60 miles a day. My fellow ebikers have newer bikes with 620 batteries. If I by a bosch 300 as a back battery will I be able to interchange it because the overall length is slightly shorter and it would not engage into the lock mechanism. Any thoughts or suggestions appreciated. Thanks, Malcolm Jones.