# Battery Sizes



## tomahawk (Mar 9, 2012)

Anyone? Bueller?


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## topnative2 (Feb 22, 2009)

lawn mower battery works great--used it on a merc 20hp 4str--- seem to remember 600amps?


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## swaddict (Dec 19, 2009)

send an email to Odyssey Batteries, I use the 925 for my 60 yammy 2 stroke, 650 cc sounds like a lot for that motor


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## tomahawk (Mar 9, 2012)

Good idea. Thanks


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## Capt Dan Medina (Apr 28, 2008)

On the 4 stroke, a lot of times the higher required amp rating is because the computer demands the power to run the engine. One downfall to the more modern engine is that they need a constant battery source in order for their computers to run all the sensors, etc. not 100%, but I know a lot of motors do not generate enough juice at idle/low speed and actually feed off the battery. Of coarse once they get into the higher rpm range they generate an excess which in turn charges the battery.
My "real world"experiences with this have been on 150 optimaxs, new 150 merc 4 strokes, yamaha 225 four strokes, 60 hp merc efi 4 stroke, etc.


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## cutrunner (Jun 8, 2010)

> On the 4 stroke, a lot of times the higher required amp rating is because the computer demands the power to run the engine.  One downfall to the more modern engine is that they need a constant battery source in order for their computers to run all the sensors, etc.  not 100%, but I know a lot of motors do not generate enough juice at idle/low speed and actually feed off the battery. Of coarse once they get into the higher rpm range they generate an excess which in turn charges the battery.
> My "real world"experiences with this have been on 150 optimaxs, new 150 merc 4 strokes, yamaha 225 four strokes, 60 hp merc efi 4 stroke, etc.


Winner winner chicken dinner


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## tomahawk (Mar 9, 2012)

It is a 20hp with a through the cowl pull start. If it won't start the motor I guess it will at least run the lights and GPS because I already bought one....doh... :-?


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## cutrunner (Jun 8, 2010)

If its got carburetors then you can get away with no battery, if its fuel injected your gonna need a good battery


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## tomahawk (Mar 9, 2012)

Yep, she's carbed. 2011 Nissan/Tohatsu


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