I am pretty sure just charging them on a slightly lower voltage will be fine. they may need a few cycles/runs to get back up to their normal capacity and punch if they have been stored for a while.
As for the car, it should be fine if its been left in a non-damp environment. if it has got wet/damp then it would be worth checking the bearings etc and replace or grease them if needed. The diff should be fine too. you will notice if anything is badly wrong with it when you first drive it.
Hope this helps
