CRAPPIE Posted August 20, 2007 Report Share Posted August 20, 2007 Hi, can anyone tell me that can I use a trolling motor battery as a starting battery for my boat, it has a 40H.P. in it Thanks in advance! Link to comment Share on other sites More sharing options...
Fishnfiend Posted August 20, 2007 Report Share Posted August 20, 2007 If you only have one battery and need it to start your 40 hp, then I wouldn't use it on my trolling motor in fear of draining too much out and not being able to start my motor with the key... You can always manually start your motor, but they get pretty tough to pull when you get up to 40 hp. Link to comment Share on other sites More sharing options...
CRAPPIE Posted August 20, 2007 Author Report Share Posted August 20, 2007 Thanks for your reply, the reason I post this message is I afraid the trolling motor battery will harm the motor if I don't use the regular starting battery. Link to comment Share on other sites More sharing options...
misfish Posted August 20, 2007 Report Share Posted August 20, 2007 I have been advised ,you can use a deep cell for a cranking battery.You just have to make sure you charge it up after every outing. Link to comment Share on other sites More sharing options...
dannyboy Posted August 20, 2007 Report Share Posted August 20, 2007 It is the other way actually; trolling motor batteries are not designed to deliver the high amperage required for starting. Whereas starting batteries are not designed to be deep discharged like trolling motor batteries. If they are used for cross purposes it will shorten their service life. They are each designed for a specific purpose, kinda like fishing rods. Dan Link to comment Share on other sites More sharing options...
BryonG Posted August 20, 2007 Report Share Posted August 20, 2007 You can (and I have) use your deep cycle battery for EMERGENCY starts.However it is hard on the battery and if used for this too many times will shorten the life of the battery. Link to comment Share on other sites More sharing options...
misfish Posted August 20, 2007 Report Share Posted August 20, 2007 (edited) It is the other way actually; trolling motor batteries are not designed to deliver the high amperage required for starting. Whereas starting batteries are not designed to be deep discharged like trolling motor batteries.If they are used for cross purposes it will shorten their service life. They are each designed for a specific purpose, kinda like fishing rods. Dan Well im guessing the boys that fish all day with a deepcell as a cranking battery, running thier wells and electronics for many years now, are wrong??????????????????? They dont seem to be having any issues. I would,nt of posted this if I wasnt doing the same thing. No issues so far this season. Even after leaving the dash lights on all night. Edited August 20, 2007 by misfish Link to comment Share on other sites More sharing options...
boatman Posted August 20, 2007 Report Share Posted August 20, 2007 Despite Misfish's anecdotal evidence to the contrary, you should not use a true deep cycle battery for cranking. They are not designed to discharge high amperage. You risk damaging the battery. Your motor and starting system will be fine. Link to comment Share on other sites More sharing options...
Gerritt Posted August 20, 2007 Report Share Posted August 20, 2007 Knowing the amount of hours Brian puts on the water.... I would take his advice... besides batteries are cheap enough... if it lasts a couple of years... who cares... Batteries are a consumable anyways so this is a mute point. Everyone at some point replaces a battery, I say have fun and take alot of pictures. Gerritt. Link to comment Share on other sites More sharing options...
misfish Posted August 20, 2007 Report Share Posted August 20, 2007 anecdotal What does this word mean? Serious! If you really look at it,how many times do you start up your motor in a day?Howlong do you run your electronics? Thanks bro. The guys that recommended me to this after last years dead battery,have been like I said,been doing this FOR MANY YEARS,and on a WEEKLY BASES. As you know, these guys are on the water,5 out of 7 days all summer and beyond that. Link to comment Share on other sites More sharing options...
lookinforwalleye Posted August 20, 2007 Report Share Posted August 20, 2007 You could always get a dual purpose battery, I used one for years and it was fine. Link to comment Share on other sites More sharing options...
boatman Posted August 20, 2007 Report Share Posted August 20, 2007 "Anecdotal evidence is an informal account of evidence in the form of an anecdote or hearsay." - Wikipedia Link to comment Share on other sites More sharing options...
misfish Posted August 20, 2007 Report Share Posted August 20, 2007 "Anecdotal evidence is an informal account of evidence in the form of an anecdote or hearsay." - Wikipedia Thank you hearsay,no hearsay here,they say and know. Link to comment Share on other sites More sharing options...
boatman Posted August 21, 2007 Report Share Posted August 21, 2007 I'm sure they do. However, second hand knowledge and informal evidence based on experience is still technically hearsay and anecdotal - true as it be may be. There is actually a formula to determine the size of the deep cycle battery required to use as both a starting and trolling motor battery. The short version is to determine the size battery you need and oversize it 20%. The problem isn't really re-starting, but rather the initial starting of the motor. Personally, I won't risk running my trolling motor off my starting battery, but I know lots of people do. Like someone said earlier...batteries are comsumable. The minor expense of a second battery outweights the savings/risk of only using one. Link to comment Share on other sites More sharing options...
Rizzo Posted August 21, 2007 Report Share Posted August 21, 2007 I'm very disappointed in wikipedia...using the word "anecdote" in the definition of "anecdotal" don't help much Link to comment Share on other sites More sharing options...
Gerritt Posted August 21, 2007 Report Share Posted August 21, 2007 (edited) Comeon guys... lets not make this academic ... it is a simple post asking for simple help... I for one will stick with Brian's advice... this guy spends more time on the water then ALOT of us combined... including myself.. I would have no issues in listening to him... agree or disagree... his suggestion here is certainly doable. Gerritt. Edited August 21, 2007 by Gerritt Link to comment Share on other sites More sharing options...
jedimaster Posted August 21, 2007 Report Share Posted August 21, 2007 A true Starting Battery will provide high amperage for starts, but will sulfate quickly if deeply discharged on a regular basis. A true Deep Cycle will not provide ample starting juice on a regular basis in the cold. The alternative is as someone mentioned is to buy a hybrid battery. Most cheap Marine batteries are actually a hybrid they provide a good mix of both. Get a cheap Marine Deep Cycle and you will be fine. True Deep Cycles have solid Lead plates to hold a charge for a long time throughout the thick plate. Starting batteries have thinner porous lead plates to maximize the acid to plate contact area. If you deeply discharge a starting battery it will sulfate much quicker than a normal deep cycle. Like I said they sell hybrids for people that don't want to have two batteries. They are a thicker less porous version between the two. The biggest advantage of having two is if one dies on the water you have a spare you can re wire to get your motor started if you have an issue with the other. Link to comment Share on other sites More sharing options...
silveradosheriff Posted August 21, 2007 Report Share Posted August 21, 2007 I think that it would be important to understand how much amperage the engine draws to start? If it is low, the issue of using the deep cell may be a moot point? Link to comment Share on other sites More sharing options...
ecmilley Posted August 21, 2007 Report Share Posted August 21, 2007 a 40 hp outboard isn't gonna be using a whole lot of amps to start to begin with, i wouldn't think it would matter either way, use the deep cycle Link to comment Share on other sites More sharing options...
jedimaster Posted August 21, 2007 Report Share Posted August 21, 2007 Better off with a deep cycle as long as it has the juice to crank your engine, than with a normal starting battery and run it dry all the time. I know with my Deepcycle trolling motor battery on 80 percent charge they wil barely kick over my engine. My engibe is a 3 liter inboard though. Anything less and forget about it. Your 40 would probably start with a handfull of D Cell flashlite batteries. Just use the deepcycle with a 40 it should be fine. No worries about your electronics, as long as you have circuit breakers and fuses. If your starter acts up it can surge your fishfinder etc... Link to comment Share on other sites More sharing options...
charlesn Posted August 21, 2007 Report Share Posted August 21, 2007 I'd use the deep cycle. Have done it on 5 boats and counting and it hasn't been an issue yet. I'd say if anything, with today's proliferation of electronic gadgetry run from the starting battery, the deep cycle comes in handy. I run 4 group 31 Interstate deep cycles and never worry about the batteries. I can run 2 livewells (fill and recirc), 2 GPSes, leave the nav lights on, pump-out, 2 bilge pumps, and start/trim my 225 HP outboard without a worry. At one point I also ran an oxygenation system off the starting battery as well. I think as long as it is not pulling double duty on the troller, you will be fine. Charles Link to comment Share on other sites More sharing options...
Tacklebuster Posted August 21, 2007 Report Share Posted August 21, 2007 I have done it when I had to help myself with a boost, because a switch was left on and drained the starting battery. Then I just let the motor recharge the starting battery. However, I wouldn't use as my starter battery. Link to comment Share on other sites More sharing options...
OhioFisherman Posted August 21, 2007 Report Share Posted August 21, 2007 Since replacing my original cranking battery years ago I have always used deep cycle batteries to start my 35 merc. Might not be a good plan with a bigger motor? 4 or 6 cylinder, mines a 2 cylinder, all my electronics run off the battery used for cranking also. I carry two extra for the electric bow mount, 12v. Link to comment Share on other sites More sharing options...
John Bacon Posted August 22, 2007 Report Share Posted August 22, 2007 I have used deep cycle batteries as a starting battery in my boat for over ten years. They seem to work fine for me. I usually get over five years of use out of a battery so it can't be all that harmful to them. I don't think that the lack of current from a deep cycle will be an issue for a 40hp; it may be an issue with bigger motors. Link to comment Share on other sites More sharing options...
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