what size amp/hour battery

[firemansam333]

hi i have an 80's evinrude 40hp vro electric start and require a battery, can anyone help with what amp/hour rating i require.
this is on a 14ft speedboat and will have a fm radio fitted and maybe a fishfinder. thanks in advance im in the uk

 

[glenn property of pam]

Re: what size amp/hour battery

basic starting battery will work fine. Work out how much room you have and find one that will fit in the gap.

 

[NYBo]

Re: what size amp/hour battery

I would go with a deep cycle. Even a Group 24 will have more than enough juice to start that motor, and it will tolerate a deeper discharge than a cranking battery. The charging output from the motor will be low.