Small Engines (Lawn Mowers, etc.): 12 Volt Battery, light hovercraft, automobile battery

Question
My question is about the battery for my light  hovercraft.

The original battery is a small-sized 12 volt battery. I am not sure about the ampere rating. As it is very difficult to obtain the small specialised battery, can I use the ordinary automobile battery which has an equivalent 12-voltage. Is the ampere rating critical?

Answer
I'm not exactly sure for your application but generlly speaking the ampere is not a critical factor.  You can usually go with more amperes but not less.

Weight may be a consideration in your application and if the battery is used for starting a small engine a larger ampere battery will provide more cranking time.  However, those smaller starter are not intended to take such heavy cranking times.  They will get hot quickly and burn-up.

Let me know if this helps.
Eric