Battery Sizes

Discussion in 'Power it up with Electronics' started by tomahawk, Jun 12, 2014.

  1. tomahawk

    tomahawk Well-Known Member

    838
    37
    403
    I was looking at my manual for my 20hp Nissan/Hatsu 4s tiller it recommends a 70AH, 800 Marine Cranking Amps/650 Cold Cranking Amps battery. This sounds excessive for such a small motor and I see allot of you guys running the small AGM's like the Odyssey's that don't come anywhere close to these numbers.
    Do they do ok? I will be using it for starting, lights and light electronics only. I'm looking to go small and light if I can.
    Thanks
     
  2. tomahawk

    tomahawk Well-Known Member

    838
    37
    403
    Anyone? Bueller?
     

  3. topnative2

    topnative2 Well-Known Member

    2,201
    379
    938
    lawn mower battery works great--used it on a merc 20hp 4str--- seem to remember 600amps?
     
  4. swaddict

    swaddict Thread Killer

    693
    43
    403
    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
     
  5. tomahawk

    tomahawk Well-Known Member

    838
    37
    403
    Good idea. Thanks
     
  6. Capt Dan Medina

    Capt Dan Medina Well-Known Member

    653
    3
    393
    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.
     
  7. cutrunner

    cutrunner Cert. Yamaha technician

    Winner winner chicken dinner
     
  8. tomahawk

    tomahawk Well-Known Member

    838
    37
    403
    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... :-?
     
  9. cutrunner

    cutrunner Cert. Yamaha technician

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

    tomahawk Well-Known Member

    838
    37
    403
    Yep, she's carbed. 2011 Nissan/Tohatsu :p