Dual purpose ok?

[fishinAK]

hello all
I suspect a variation to this question has been asked b4...but I cant find it.

So its time to replace my batteries. Currently I have a start and a deep cycle, both grp 24.

in my shopping it seems that the dual purpose batteries offer just as good (in most cases better) numbers (MCA and AH) than the deep and start batts. So is there a problem going with 2 dual purpose batteries vs a 1 deep and 1 start?

Oh most of my boat time is 2 nite trips w/ miminal eletronics on over nite, chartplotter, Wallas stove, fan, vhf, and a little lite or 2. My outboard is a 200 hp efi yami.

Please any and all thoughts apprecaited.

Oh ya 1 more thing. I read somewhere that a yamaha ob is not supposed to use agm batts. anyone else heard this?

Thanks for any and all imput!

[Sea Wolf]

fishinAK-

If you like the dual purpose, use 'em!

I use only deep cycle because the have plenty of amps to start a 90 hp Yamaha, and the deep cycle, with heavy, but simple plates, last longer than other batteries with thinner, more numerous, plates.

My batteries go 5 years or more, I just keep them charged and run the anti-sulfation program on the charger every 4-6 months.

I also use 4 group 27's, rather than 2, so have got about 460 amp hours aboard.

Simple, heavy, reliable. The KISS Principle, again!

Never heard of not being able to use AGM batteries on a Yamaha!

Joe.

[jennykatz]

How do you use the anti sulfation program on your charger?

I use one group 27 a 115amp hrs duel purpose and one group 24 with 65 amp hours( starter)

I have a 06 f115 yamaha with a 35amp hr alternator For day trips it's working fine but for overnights it might be a problem with a Tundra Fridge,wallas,radio, and lights etc.

If we start cruising more then a few days at a time I will add another group 27

[matt_unique]

I too use nothing but deep cycle. I have three 600CCA/750MCA deep cycle bats on Napoleon. They have provided plenty of juice for house needs and the Suzuki 150's start easy.

[20dauntless]

I have two group 24 batteries, one starting and one deep cycle. I never use the starting battery, and the deep cycle has always had enough power to start the engine, even after a couple of days anchored. My boat doesn't use much power, since I've got LED's in all the lights and no refrigerator. About the only draws are lights (hardly any), Wallas, and occasional use of speakers.

[Sea Wolf]

[Best Day]

I have 4 trojan 6 volt deep cycle batteries. 2 as house and 2 as starting. Plenty of power to get me through 3-4 days then I need to charge them up. I have a heavy power draw with fridge, separate freezer, livewell and more.

I believe the 06 115 Yamahas have a 25 amp alternator like my 07 90 Yamaha.

Bill

[thataway]

You should not use any GEL batteries with an outboard (not just Yamaha). The reason is that any charging voltage over 14.1 volts will damage a GEL cell (not an AGM). Although AGM's have slightly different charging characteristics than the lead acid, they tolerate the higher and less regulated voltages (14.4 to 14.5 volts) of outboard motors well.

NOW, a pet peeve. Don't talk about group 24 or group 27 batteries--there is so much variation in the capacity between each of these groups, to make it less meaning full. The group number is just a case size. You can find a group 24 battery with 60 amp hours or 90 amp hours. A group 27 from 70 to 110 amp hours. What you need to know is the amount of power available for starting (that is Marine cranking amps or MCA) or some form of long term discharge capacity--usually measured in amp hours or reserve capacity to a certain discharge point. You need to know how these are measured by each battery manufactuer. For example 1 amp x 100 hours is 100 amp hours, but so is 10 amps for 10 hours--and the latter is actually a batter battery.

For the most part reserve minutes are measured with a 25 amp resistive discharge load until the battery reaches 10.5 volts (a very low voltage and enough to damage the battery). If it is a 150 min Reserve capacity, that means that the battery can sustain a 25 amp discharge for 150 minutes before reaching the terminal voltage of 10.5 volts.

Amp Hours are measured by the amount of discharge current for 20 hours to reach an end point of 10.5 volts. Thus a 100 amp hour battery can run 5 amps for 20 hours before terminal voltage of 10.5 volts. HOWEVER< you should never discharge batteries to more than 12.2 volts for best longivity.

The deep cycle batteries are heavier and have thicker plates, and thus withstand more repeated and deeper discharge cycles.

From the above posts, I know the most about the batteries in Best Day-' he has two banks of Trojan 105's I know that these are 6 volt batteries, in series to give 12 volts and I can look up on the tables to find what the capacity of these batteries are.

For the most part outboards require relitatively low starting capacity or Marine cranking amps--so that even deep cycle golf cart batteries, like the Trojan 105's will easily start any of our engines.

Personally I like to use the group 27 or group 31 with the highest capacity I can find. The only reason to use group 24 batteries, is where the fit is limited; (for example in the lazarette of the C Dory 22. Best to use the heaviest (thickest plates) you can get in the case size.

[jennykatz]

I stand to be corrected it is a 25amp charging system on the f-115 I was thinking of my old Suzuki I miss that engine