What size/type of battery do I need?

[PaulGooch]

If its wrong them please explain why so many people using leisure batteries for starting engines suffer so many issues with defective batteries, and why even the manufacturers tell you not to use them for high drain applications such as starting engines. Are they all wrong.

They are not wrong, they don't say that.

Leisure batteries have CCA ratings, that's Cold Cranking Amps. My guess is, that's for cranking the engine, not SWMBO's hair dryer.

As for starting an engine with a (proper) deep cycle traction battery....... not a chance in hell. These batteries are for domestic use, i think you have things backwards in your head here.

A leisure battery is perfectly suited to marine use. It's basically a car battery that's been beefed up a bit with pinned plates, for extra support. Ideal for the rigours of boating or caravanning.

 

[Deefor]

Surely if the OP's engine is only 20hp then one or two "leisure" batteries would suffice?

2 x 75ah LB's work well for me with a Honda BF20 outboard and a 40w Waeco fridge running 24/7 and that's with me moored up for 14 hours a day.

 

[sailorman]

Hello, need advice on a battery for my boat? It has a 2 cylinder 20hp Volvo inboard engine. Will a standard car battery be good enough?

yes