# Motorcycle battery for starter?



## batman (Sep 3, 2011)

Thinking about upgrading to an electric start Yamaha 20 HP outboard.Can I use a small motorcycle battery for starting,or do I need a full size starting battery?I already have 2 deep cycles in the boat and would like to save weight.
Thanks,
DanD


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## Zum (Sep 3, 2011)

What are your 2 batteries used for now?
1 TM,the other accessories?
If so I'd use the accessory one to start my 20hp.If the 20hp has a charging system,you could use it to charge that battery up abit, while running.
A motorcycle battery probably would work,depending how many times you start your outboard in a day.
I don't think it takes to much to turn over a 20hp.


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## LonLB (Sep 3, 2011)

I used a harely softail battery in a Camaro I use to race in SCCA events.
That car put out around 300hp, 375lb ft at the wheels.

Started it great every time.


HOWEVER that was with an alternator. I would be concerned about the charging ability of that motor. The other thing is that it would start right up. So a boat motor that is cold blooded could cause you some problems.


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## batman (Sep 3, 2011)

both deep cycles are use for the TM, i have them wired in sequence.
Yeah I don't think it would take much to start the 20,it also has a 10A alternator on it .
DanD


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## fastcajun (Sep 3, 2011)

i have used lawnmower batteries for starting before, but you cant run any other accsy. with it other than maybe nav. lights.


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## batman (Sep 3, 2011)

The deep cycles take care of everything,just planning on a small battery for engine starting only.
DanD


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## crazymanme2 (Sep 3, 2011)

I use a small battery just like you want to do with no problems.I run my lights, bilge pump,graph,GPS,& use it to start my motor with no problems.My Merc has a charging system.The biggest draw is the bilge pump as all my lights are LED's.


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## seasprite (Sep 3, 2011)

I own an 1856 Jon boat with a 50hp jet motor. I use a car battery for starting and a deep cycle for the TM. I'm a guide and I use both batteries hard with no trouble at all. Like they said if you start the motor enough with a small battery it won't last


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## batman (Sep 6, 2011)

Thanks for the info guys.
DanD


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