# Smallest battery



## lpg (Sep 1, 2015)

Shedding some weight in my boat (powerpole, and 2 12v batteries..)

Going to build a small box for my trolling motor batteries to use only when TM is being used, so I need to buy a single 12v battery which will need to :

1)start an evinrude 60 (etec)
2)run gps
3)run bilge pump when need be

So, what im obviously worried about would be having the juice to a)start the motor b) run bilge pump in emergency, but the motor can be rope started in emergency..

So what is the smallest battery you recommend using? a model number would be great..


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## Vertigo (Jun 3, 2012)

Check out motorcycle batteries. Evinrude specifies big batteries for their motors because they want to be sure they'll start reliably under adverse conditions, even if the battery is low. A 100 CCA battery would do the trick. Contrary to popular opinion a bilge pump is a convenience not a safety item. A big enough hole or wave will overcome any bilge pump. A scared man with a big bucket is best in that kind of situation.


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## pt448 (Mar 22, 2014)

lpg said:


> Shedding some weight in my boat (powerpole, and 2 12v batteries..)
> 
> Going to build a small box for my trolling motor batteries to use only when TM is being used, so I need to buy a single 12v battery which will need to :
> 
> ...


http://www.lithiumion-batteries.com/lithium-marine-batteries.php

These are only 13 lb., but very pricey.


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## tomahawk (Mar 9, 2012)

I use this one on my skiff. Been using it for a year with no issues effortlessly cranks my 20 Nissan 4s. The motor manual called for some ridiculous number of CCA's.
https://www.chromebattery.com/y50-n18l-a3-high-performance-power-sports-battery.html


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## Blue Zone (Oct 22, 2011)

lpg said:


> Shedding some weight in my boat (powerpole, and 2 12v batteries..)
> 
> Going to build a small box for my trolling motor batteries to use only when TM is being used, so I need to buy a single 12v battery which will need to :
> 
> ...


Check out the Odyessy 925. I put one in my son's Whaler as a cranking battery for a 20 and runs the gps without issue. It's compact, not as light as lithium and not as $ as lithium. It can be mounted in any position except upside down.

I spoke to the guy at the Lauderdale Show to see if will be ok for my skiff which will have a 40 or 50; he said no problem.


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## lpg (Sep 1, 2015)

I see on the etec manual it calls for 640 cca.. That's not even close to the 100 mentioned here. Is evinrude really calling for 6x what's necessary??

Thanks for the help


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## Travisloyd07 (Jan 31, 2014)

I run mc battery for my 20hp EFI yammy, it works great. Highest cca from a mc battery is going to be about 350cca. There are some small sealed lead acid batteries that might work for you. I run a dcm0040 in one of my boats. It runs a gps, fuel pump, lights , and starts a 320CI 160hp aircraft engine(not fuel injected). It only has 375 cca but only weights 28lbs. You might consider the dcm0055 it is a group 22nf. It has 650cca it weights about 38 lbs. I know someone else one here has use it for a tm ipilot 55lb battery. At 38 lbs you could run a sc75u optima with 750cca. Odyssey pc1200 has 550cca and is the same size as the dcm0040 but double the price. If your not worried about pruce I'd go with lit - ion. I'm in the central fl area and could let you try anyone of the ones I have if your near me.


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## Net 30 (Mar 24, 2012)

I'm sure everyone wants the lightest battery possible at a decent price. Question is, why would any engine manufacturer specify a battery that's much larger than needed? 

I was told at a show by a Yamaha rep that the you shouldn't mess with the electrical needs of feeding all the electronic components of the motor?


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## jonrconner (May 20, 2015)

Once the engine is running all the electrical needs are taken care of by the alternator, the only thing the battery has to do is have enough power to spin the engine over for starting, which isn't really all that much. Lots of motorcycles have much more cranking resistance, i.e. a 1200cc twin Harley, and start fine with a very small battery.
JC


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## Vertigo (Jun 3, 2012)

Long ago, the electrical output of outboards was not regulated, and a big battery was less likely to get over charged. The output of modern outboards, including ETECs is regulated, and a small battery is no problem. A 60 hp ETEC can be hand started, and requires no external electrical input to run normally....so what the OP really needs is something with enough capacity to turn the motor over a few times and to run electronics and pumps. If not a lot of pumps are running, and the motor is not started and stopped continuously, then a very small battery will do. 100 cca is not out of the question. As noted above, check out motorcycle batteries. Some pretty small batteries start some pretty big motors.


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## lpg (Sep 1, 2015)

How about this? LI-ION has me worried with fires thought...


http://www.amazon.com/Battery-Tende...1452086196&sr=8-2&keywords=motorcycle+battery


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## noeettica (Sep 23, 2007)

You should get one and let us know how it does ...

I run 2 Sla's when a starter is not needed
18 ah one for electronics and one for the bilge pump
and Trim and Tilt

If you turn off your electronics (The spikes during
starting will DESTROY your electronics !!!)
You could use
a switch that allows for parallel operation
for starting . That should do the trick

Also install a diode isolater to allow both to
receive charge current while under way ...


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## tomahawk (Mar 9, 2012)

I dug up the manual on my 2007 20HP Nissan 4 Stroke, 650 cold cranking amps...


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## swaddict (Dec 19, 2009)

get it one that matches your CCA's, they're rated for a reason by the manufacturer


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## jonrconner (May 20, 2015)

The manufacturers recommendations are so overblown as to be laughable, they're probably driven by the battery makers who want to sell the batteries that have the highest profit, i.e., automotive batteries that they make millions of. I just looked up the recommended battery for a 2015 V8 Silverado, 720 cca, and that's a battery that should start a 5 liter engine at -40 F when everything cranks at many multiples harder than any temp in FL, plus batteries don't put out their full power at lower temps. 
Just get the lightest battery you can find that's made for motorcycles, ATVs, snowmobiles and other small engine vehicles, one of them have any less electronics than a small boat , unless you have a bilge pump and want to leave the boat at mooring for weeks unattended.
JC


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## Net 30 (Mar 24, 2012)

jonrconner said:


> The manufacturers recommendations are so overblown as to be laughable, they're probably driven by the battery makers who want to sell the batteries that have the highest profit, i.e., automotive batteries that they make millions of. JC


Why would any outboard engine manufacturer (most of them foreign) give a crap about battery makers and their profit margins? Yamaha, Suzuki, BRP and Honda all make motorcycles and they don't specify larger then necessary batteries for the bikes…………...


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