Battery Question

[CThomps]

I've got a 2003 200hp Salt Water Series Mercury.  

It's about time for a new battery.  I think the current one may be under sized but I can't remember off the top of my head what size it is.  I think it's either a 650 or 800

What size battery is best?  I've read for bigger Merc's 1000amps is best.  But that was mainly for Optimax's and Verados.

[wingtime]

I think the biggest question is how long is your battery cable run?  If you have a long cable run that can lead to a voltage drop at the starter.   I have a Merc 200 on my boat and it easily turns over.  I have a plain old west marine group 24 marine starting battery.  However my cable run is very short.

[CThomps]

Current battery is under the center console.  So I'd guess my run is likely 15ft or so.

[fitz73222]

I suggest a Group 27 or 29, 1000 CCA for under the console; actually two of them would be best. I like the Autozone dual purpose about $115. ea. 3 things in this world to spend good money on; The best mattress you can buy followed buy the best shoes you can buy with good arch support, and the biggest battery(s) that will fit your boat or truck...

[seabob4]

I suggest a Group 27 or 29, 1000 CCA for under the console; actually two of them would be best. I like the Autozone dual purpose about $115. ea. 3 things in this world to spend good money on; The best mattress you can buy followed buy the best shoes you can buy with good arch support, and the biggest battery(s) that will fit your boat or truck...

^^^^^^^^

8Ds if they'll fit!  

[CThomps]

So biggest battery can't hurt?  

If so then biggest battery it is.  

Thanks guys.

[GoneFission]

I suggest a Group 27 or 29, 1000 CCA for under the console; actually two of them would be best. I like the Autozone dual purpose about $115. ea. 3 things in this world to spend good money on; The best mattress you can buy followed buy the best shoes you can buy with good arch support, and the biggest battery(s) that will fit your boat or truck...

Don't skimp on condoms or accountants, either!      

[seabob4]

So biggest battery can't hurt?  

If so then biggest battery it is.  

Thanks guys.

Keep in mind, Thomps, the equipment will only draw what it needs to operate, be it starting a motor or running a nav lgt.  You could have a nuclear power plant under that console, the stuff is still only going to draw what it needs.  So, it's nice to have all that reserve when you REALLY need it!

[John Jones]

3 things in this world to spend good money on; The best mattress you can buy followed buy the best shoes you can buy with good arch support, and the biggest battery(s) that will fit your boat or truck...

 

 

[Capt. Bob]

So biggest battery can't hurt?  

If so then biggest battery it is.  

Thanks guys.

Keep in mind, Thomps, the equipment will only draw what it needs to operate, be it starting a motor or running a nav lgt.  You could have a nuclear power plant under that console, the stuff is still only going to draw what it needs.  So, it's nice to have all that reserve when you REALLY need it!

And that brings you full circle to the original response to your query. As Wing stated ,all that power is only as good as the conveyance system (cables) that carry it to the motor. You should consider, along with the size of the battery, the cable gauge also. All that power won't help if the conductors are undersized. You will eventually cook the starter by spinning it at too low a voltage. I'll assume  :o  that the "about 15 ' is one way. You'll need to compute the run using the total length (up and back) between the battery and the motor.

The calculator will use a one way run for sizing but it computes the wire size based on the total run distance.
Link to calculator.
http://genuinedealz.com/voltage-drop.html

Good luck.

[seabob4]

2GA is what you want...

[flounderpounder225]

2GA is what you want...

X2   I went with 1 AWG just because the price was not that much different, but either will give you max current carrying capability, and never have a worry.

[gran398]

As recommended run 1-2 AWG regardless of the run length...and you'll never worry. Fifteen extra dollars ten years from now thirty miles offshore...priceless.