basic help for a newbie
You can hook any 12v battery up, and things should work, but a deep cycle is best. It''s plates have been designed to handle a long, slow drain, and should handle many cycles. You will need a way to charge it though!
Most O/B''s over say 7hp usually (but not always) have an alternator built in. I know Honda''s starting at 8hp do, so probably others in that range also.
As far as your shroud is concerned, you should check to see if the rig is centered. Use your main halyard. Bring it over to one of your chainplates and cleat it off, keeping a steady tension on it. Then bring it over to the other chainplate. It should be at the same height on the chainplate as on the other side. If not, then your mast needs to be moved over. Do that by losening one turnbuckle and tightening the other. Check from side to side as you do this, and you will eventually get it so the halyard hits the same height. If this does not happen, you either have a shroud that is a different length, or a bent rig.
Good luck! Happy sailing!