That's a lot of money to spend on an experiment! You should buy a used mower and play with it first! As you will find that you have to take it apart in many pieces. For such a small project you could save a lot of money and get what you need from a wet cell without a problem! Yes you will need to have a battery, some sort of power to the cell.
You would have to have a dryer and separator any how so movement isn't an issue.
Smack cell would suit you just fine ! Then graduate.
Its done right or its not done !
Hail HHO.