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Author Topic:   Battery Choice for Non-Cranking Usage
Cpt Quint posted 02-25-2004 09:24 AM ET (US)   Profile for Cpt Quint   Send Email to Cpt Quint  
I have a boat with two batteries. One is a battery for engine starting, and the other battery is for a fish finder, trolling motor, console electronics, livewell aerator. The "regular" [cranking type] battery being used for the electronics is taking a beating. My fishing habits have changed and I'm using the trolling motor and aerator all the time.

What is a better battery for the electronics side of my two battery set up?

What is the difference between a deep cycle battery and a "combination" battery?

jimh posted 02-25-2004 09:36 AM ET (US)     Profile for jimh  Send Email to jimh     
People seem to have entire websites devoted to batteries. Here is an article:

JohnJ80 posted 02-25-2004 11:01 AM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
I think you want a battery that is pure deep cycle on the electronics side. Most of the electronics will be able to run well below what you would safely want to do with the trolling motor.

Since you are running the trolling motor a lot, you are going to suck down the battery more. There really is no alternative to having a good deep cycle battery.

West Marine/Boat U/S sells some huge capacity batteries that are used for golf carts.

The other suggestion, and one that works well for me--although our fishing styles are different (I run from place to place and troll when I'm there)--is one of the devices that will charge your battery from your motor's alternator. I use the stealth one charger from . In this way, I can be out fishing all day, trolling to my heart's content and come back with a full battery. The speed with which you can charge your battery is a function of the current output from your alternator. The motor I have has a lot of output so charging the battery is a simple and quick deal.

You could also add a second battery in parallel with your current electronics battery. I would recommend that both batteries be the same chemistry/type, same age, the same manufacturer and the same capacity. This would give you 2X the amp hours that you have today.


lhg posted 02-25-2004 01:50 PM ET (US)     Profile for lhg    
A COMBINATION marine battery has both starting and deepcycle capabilities.

The way Quint is decribing things, I would replace the starting circuit battery with one of the dual PURPOSE batteries, and put the electronics on that, separate from the electric trolling motor. I use the dual purpose batteries (Everstart brand from Walmart) on both engines in my Whalers with excellent results. As is widely known, the deep cycle function permits constant charge/discharge cylces without damaging the battery. Not so with a starting battery.

This brings up another item mostly overlooked with outboards during buying decisions, but of considerable value - alternator output on your engine, and the RPM's required to generate same. Some models are hoplessly pathetic, such as the Yamaha 2-stroke 70's at 6 amps (sorry Jim!) or even the Yamaha 90 at 10 amps. So if you're a fisherman or cruiser, before you buy an engine, look at it's charging capabilities. Because Mercury has for years catered to the bass and offshore fishing markets, their engines often have the highest alternator output of any brand.

JohnJ80 posted 02-25-2004 09:07 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
I agree with LHG on the alternator issue. It is why I bought the motor that I did - a 75HP FICHT Evinrude. It has 35A on the alternator and you can add an additional one (leg) for another. I can't for the life of me understand why any manufacturer would put such wimpy alternators on a motor (<12A). You would have to run hours to get a half discharged battery back up to full capacity - a dangerous thing.

I would put more battery capacity on the deep discharge side and keep the electronics over there. The power used by the electronics will be small in comparison to the trolling motor. The electronics (vhf, FF, GPS) are probably not as sensitive to the battery voltage as the trolling motor is (can go below 10V and still operate just fine). So, you would still have more capacity to run mission critical electronics for a long time after your trolling motor wasn't running well.

I guess I always worry about being able to crank the motor so I like to keep them separate. this is especially true with the EFI or DFI motors. They need to have a good electrical supply more so than a 2 stroke normally aspirated engine does.


newt posted 03-02-2004 11:20 AM ET (US)     Profile for newt  Send Email to newt     
A "dual purpose" battery is a combination between deep cycle and starting.

To plagerize Don Casey from the BoatUS site...

"A dual-purpose battery has appeal for those who wish to avoid the complication of multiple batteries. Something of a hybrid, this type of battery typically is more starting battery than deep-cycle, but it will tolerate modest discharge without damage. If you only want to run the stereo and maybe a couple of lights when the engine is silent, this can be a good choice"

LHG posted 03-02-2004 01:32 PM ET (US)     Profile for LHG    
Newt - I think you've got to remember West Marine/Boat US is in the business of selling high priced batteries. From years of experience with my twin engined Whalers, with lots of extra electrical loads from extended cruising and fishing, I have found the combination batteries to be excellent. It seems to me the dual cycle battery is only necessary if one is running an electric trolling motor. It makes no sense to me to load up a Classic Whaler with all kinds of batteries and switches and charging gear.

The dual purpose batteries, incidentally, are quite a bit heavier. With a marine battery, always remember to replace it before its time. This is still a lot less expensive and cumbersome than having multiple batteries in the boat. Any V-6 outboard in good operating condition can be pull started if necessary also.

Moe posted 03-02-2004 02:03 PM ET (US)     Profile for Moe  Send Email to Moe     
Dual-purpose and "combination" are the same thing. They're deep-cycle batteries that give a little more cold cranking amps (CCA) and a little less amp-hours. You can start most outboards with deep-cycle batteries even if they aren't dual-purpose.

However, if you own an Opti (and maybe also HDPI), look carefully at the owners manual's recommendation for minimum CCA. You may need a pure starting battery to meet that requirement. That's not to say that you can't start an Opti with a deep-cycle or dual-purpose even if it doesn't meet the minimum CCA requirements.

You'll get a little more time on the trolling motor with a pure deep-cycle than a dual-purpose.


jimh posted 03-04-2004 09:35 PM ET (US)     Profile for jimh  Send Email to jimh     
[This thread has been re-written to remove references to "dual-cycle batteries" as there apparently is no such nomenclature in common usage.]
Chuck Tribolet posted 03-04-2004 10:12 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
LHG, I've got a 90 HP V4 Evinrude, and it can't be pull
started as there's no place to attach the rope. And from
looking at the factory service manual, which also includes
the V6's, they can't be pull started either for the same


LHG posted 03-04-2004 10:21 PM ET (US)     Profile for LHG    
Whoops, sorry Chuck. I just assumed all the brands had the notched flywheels and lawnmower style pull rope. I have pull started one of my Mercury 200's, and also the 6 cylinder 115's quite easily. It's not as difficult to pull one of these over as one would expect.
Cpt Quint posted 03-09-2004 04:53 PM ET (US)     Profile for Cpt Quint  Send Email to Cpt Quint     
walmart is soliciting them as dual purpose. had a marine mechanic tell me that it has to do with the boat. where deck space or weight distribution is an issue than a dual purpose will be fine(less than 40hp and less than 32 lbs thrust.)one dual purpose battery here will work great. If you have 16 ft+ and the weight and space isnt an issue and your motors 50+and trolls 40+ than 2 is the way to go,0ne to crank, the other deep cycle.
JBCornwell posted 03-09-2004 06:37 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Ahoy, Capt. Quint.

As recommended above, I use a single dual purpose battery for all of the purposes you mention except the livewell. Never had a problem.

My choice is the Everstart Marine Max, 850 CCA battery from Wal Mart.

Red sky at night. . .

gcl posted 03-16-2004 10:12 AM ET (US)     Profile for gcl  Send Email to gcl     
solar charger: Has anyone had any experience with using a solar battery charger for either their main battery or deep cycle trolling motor battery ?
craig posted 03-16-2004 02:23 PM ET (US)     Profile for craig  Send Email to craig     
For a small whaler I would stick with two AGM dual purpose batteries. They have good starting capacity as well as fair amount of amp hours for your electronics. I would put them on a switch and dedicate one to starting and one to the rest of the electronics. For a larger boat I Would have one AGM for starting and two or more 6V Golf batteries wired in series to produce 12V. You can get them at West Marine or most larger batter distributors. The advantage is the golf cart batteries offer many amp hours for the dollar and can survive as many as 1000 cycles. Here is a link to them at Westmarine:

If price is no object and you want the best batteries then check out Rolls Batteries here:

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