PDA

View Full Version : Battery Question



mistertwister
02-28-2006, 10:51 AM
I have a 1998 Pro Team 175 that i ordered with a 9.9 mercury.(all of my local lakes have a 10hp limit). I have always used the cranking battery for the motor and the deep cycle battery for the trolling motor. What i would like to do this year is replace both batteries with deep cycle batteries and wire them in series. This way, my trolling motor will have both batteries as a resource (allowing me to troll all day) and the 9.9 can use them as needed. Will this work or is my logic flawed here? Thanks for the advice.

Bushrod
02-28-2006, 11:10 AM
Well...you can certainly do what you want to do...just remember that the additional drain on the power sources may just leave you without enuff cranking amps to start your engine after a long day (or night) of fishing...especially if you're running a 12V light for night stalking...I know that from experience...after fishing all night, I wound up having to paddle my bass boat over 3 miles back to camp (against the wind)...won't ever have that kinda "brain fart" again...lol....

Bushrod

CatFan
02-28-2006, 11:24 AM
Wiring batteries in series gives you 24V. You probably want to wire them in parallel, which still gives 12V, but almost double the capacity. With your 9.9, the starting load would be pretty small, and it would probably work out. The only downside is if your TM runs the batteries down, you may not be able to crank the outboard. But cranking a 9.9 by hand is too bad compared to the big gas-suckers.

Crappie Chatt
02-28-2006, 11:24 AM
Ok, let me get this straight. You want to use both batteries at the same time? If so, wire them pos to pos and neg to neg. The problem I see with this is,,, your locators will get interferance from one or both. Also you still may run the starting battery down till it won't start the motor. But with a 9.9 I'm sure the rope will start it. The charging system on a 9.9 will NOT recharge enough not to have to recharge after each use. Trolling motors that have speed numbers, as 1 thru 5, drain the batteries MUCH faster than those that have varaible speeds. Logic is fine and the deep cycle batt. will have enough cranking amps to start the 9.9. Use 1/0 battery cable to make the connections. Hope this helps and Good Luck fishin' <*)}}}><

FisherMike
02-28-2006, 11:32 AM
I've been doing it that way since 2000 when I bought my 25 Johnson and have yet, I take that back, one time ran the batteries down enough that the motor wouldn't start.
Then I just drift fished for about 15 minutes and the batteries built back up enough to start the 25.
Also, you can start that 9.9 with one hand all day long.

mistertwister
02-28-2006, 11:35 AM
My fault catfan, i meant to say parallel. I have a 12 volt trolling motor.
My outboard does have a rope, so running out of battery is not a problem. My main issue is trying to increase my capacity for trolling, without shoe-horning a second deep cycle battery in the compartment. Currently i have 1 each of deep cycle and cranking. I think by replacing both with identical deep cycle that i will get more use out of them. Now, the problem may be with the electronics. I have both a console and forward mounted sonars. Thanks for all of your alls input.

Eager Beaver
02-28-2006, 11:38 AM
The reason for 2 different batteries is for the draw that the motors take. The battery for the big motor is built to have a rapid draw on the battery, while the Deep cycle battery is meant to be drawed down slowly. If you use a deep cycle trolling motor battery to start the main motor it will not last long. Minn Kota make's a battery that you can use for both the big motor and trolling motor though. You could get 2 of them and hook them parrellel.

mistertwister
02-28-2006, 12:06 PM
What about optima batteries. THese things are unbelievably expensive. But, they do have a blue top that is dual purpose. Cranking and trolling. Can anyone on here justify the cost of these babies?

CatFan
02-28-2006, 12:10 PM
If you use a deep cycle trolling motor battery to start the main motor it will not last long.

Cranking an outboard doesn't draw enough to really make a difference. Many people use deep cycles for cranking big outboards because running livewells and fishfinders etc. makes the use more of a deep-cycle load. You will do more damage deep cycling a cranking battery than cranking with a deep cycle. You do need to be aware of the CCA of the battery, because some outboards need high CCA to allow the computer to function properly while the battery is under cranking load.

Barnacle Bill
02-28-2006, 01:13 PM
We have been running that setup for years on my buddies Tracker. 2 deep cycle batteries in parallel used for trolling and starting a 25hp Merc. No interference with the electronics and never had to hand start. They are big batteries (group 31 I believe). Its recommended, when doing that to use identical batteries and the same age.

Moose1am
02-28-2006, 04:15 PM
I have two Optimas. One is a combination cranking/deep cycle that I use for starting my 35hp johnson motor. The other is strickly a deep cycle that I use for the trolling motor only. Both are blue tops or made for a marine environment.

I am on my third year with these optimas so I'll let you know in another three years if they were worth the money. :)

From all the literature that I read I feel that they will get me 6 years of good use.

I like them so far

A good regular battery cost about 60 to 80 bucks. The optimas cost me around 100 and 120 each. So if I get twice the useage out of them they will have been a good investment.

They do charge up fast and hold the charge for over a year. So that in and of itself is a good thing

They also are very resistance to boat vibrations due to the way the lead places are spiral bound in the glass mats.

One optima battery will run your trolling motor all day long. I fish a lake that is limited to trolling motors only and I can fish it all day long without any problems as long as the wind is not too strong.




What about optima batteries. THese things are unbelievably expensive. But, they do have a blue top that is dual purpose. Cranking and trolling. Can anyone on here justify the cost of these babies?

Bugtussle
02-28-2006, 07:33 PM
Cranking an outboard doesn't draw enough to really make a difference. Many people use deep cycles for cranking big outboards because running livewells and fishfinders etc. makes the use more of a deep-cycle load. You will do more damage deep cycling a cranking battery than cranking with a deep cycle. You do need to be aware of the CCA of the battery, because some outboards need high CCA to allow the computer to function properly while the battery is under cranking load.

So would it be better to get a battery that is a combination deep cycle/marine starting battery instead of just a plain marine starting battery if you are also running the depth finder, livewell, etc. off of the starting battery?

CatFan
02-28-2006, 09:14 PM
So would it be better to get a battery that is a combination deep cycle/marine starting battery instead of just a plain marine starting battery if you are also running the depth finder, livewell, etc. off of the starting battery?

Usually yes.