Recommended Battery System ffor 25hp Outboard

[gronski]

I recently purchased an older Yamaha 25hp 2 stroke with electric start (Model 25ESHS). I'd like to buy a battery to use the electric start.

The motor is being used on a tender so I have very little need for any other electrical draw other than a starting the motor (ie: There are no lights or electronics on board).

What is the smallest battery I can get away with? Specific product recomendations are welcome. And how do I keep this battery dry (are there some small batteries with integrated cases?)?

Thanks,
Chris I

[tripleb]

Hello gronski,

Any "group 24" battery would work just fine. You can buy a battery case from your local marine supply store.

If you do not want to keep the battery in a case, take a look at the Optima line of batteries:

http://www.optimabatteries.com/publi...fo/marine.html

These are Gel Cell technology and being in the "weather" should not hurt them.

[gronski]

The engine and battery are for a small 10' inflatable tender. I'm concerned that if I don't get a case, splashed water create a bridge between the negative and positive terminals. What would happen if it did?

Chris

[Ken]

Chris,
Good question - if it were fresh water I would not be concerned, but salt water would be a conductor - just how much, my gut feel says the current draw would be in the hundreds of milliamp range - not enough to discharge the battery while running, but if left for a couple of days, yep.
Better to get that battery in some kind of enclosure - lightweight and corrosion proof (but not air tight).
Also, check the current draw for that starter - should be listed on the id plate on the housing. I bet you could get by with one of those small garden tractor batteries like I have on my Kubota diesel - I'm pretty sure my 3 cylinder diesel is harder to crank than your 3 cylinder two stroke. There's a big weight difference between a size 24 and garden tractor battery.
Good luck [img]smile.gif[/img] ,
Ken K