Battery Size Questions

[rippin-lips]

I have a group 29 for my 12v trolling motor and I'm wanting to add a second battery wired in parellel so I have more run time on the water. Is it okay to use a smaller battery such a a group 24 or do I need to match the sizes?

[bullett 21]

Stay with same size .try not to mix and match .Not saying it wont work ,might have issues down the rd .

[rippin-lips]

That's what I figured but wanted to ask. Well I guess the good thing is I'll always have plenty of power.

[Sam]

Same sizes.

[mjseverson24]

if you hook the two in parallel you will essentially have two of the series 24 batteries. now that being said two 24's are better than 1 29. but that also being said 2 29's are better than 2 24's except on the wallet. you will not do any damage to anything by having two mixed matched batteries though, just not maximizing the 29's potential thats all. another option that might work for you, buy the 24 keep them seperate and when one batterie gets wore down switch the leads to the other one, that way you will get max performance out of both the bateries. just a thought. if it were me I would buy another 29, but do what is best for your needs an budget. 

 

Mitch

[rippin-lips]

Yeah I thought about buying a smaller battery and just swapping them out when the larger one dies but that'd defeat the purpose of wanting to wire 2 in parallel for the extra life I'd get. At least that's what I've read. 2 in parallel will last longer then 2 by themselves. I'll just stick with the same size. The difference in price is like $15. No big deal.

[Optima_Jim]

Whenever two or more batteries are wired in series or parallel, they should always be identical not only in size, but age and type. The charging characteristics of dissimilar batteries can shorten the lifespan of both batteries, even if the only difference is age.  Internal resistance can build in batteries as they age, so it may take more time to fully-recharge the older battery than the newer battery.  AGM batteries have far lower internal resistance than flooded batteries.  Either scenario could leave one battery chronically undercharged, while the other is always being overcharged.  Do people wire dissimilar batteries together? All the time and they can get away with doing it in some instances.  However, in a trolling motor application, you will be deeply-discharging and cycling these batteries far more than someone who is using two dissimilar batteries to start their diesel truck.

 

Jim McIlvaine

eCare Manager, OPTIMA Batteries, Inc.

www.pinterest.com/optimabatteries

[rippin-lips]

Thanks Jim. I just bought another group 29 battery. Amp hours @1amp are a tad different but not by much. 114/125 The ages are a 10 month difference. 6/12 - 4/13 Both are Everstart marine deep cycle batteries but one is the regular and the other is a maxx. Not sure what that means exactly.

[Optima_Jim]

I'd be interested in hearing how that works out for you.  If you can remember, please update this post when you replace one or both of those batteries.  Thanks!

 

Jim McIlvaine

eCare Manager, OPTIMA Batteries, Inc.

www.pinterest.com/optimabatteries

[rippin-lips]

I'd be interested in hearing how that works out for you. If you can remember, please update this post when you replace one or both of those batteries. Thanks!

Jim McIlvaine

eCare Manager, OPTIMA Batteries, Inc.

www.pinterest.com/optimabatteries

Not exactly understanding what you are meaning. Are you saying that I'm cutting into their life span or ?

[topwaterrob]

Not exactly understanding what you are meaning. Are you saying that I'm cutting into their life span or ?

 

Yep I believe he was....  Makes sense to me....Are you using that much juice that you need a seond battery?  I fish all day with mine and they are in a series....

[rippin-lips]

Yep I believe he was.... Makes sense to me....Are you using that much juice that you need a seond battery? I fish all day with mine and they are in a series....

90% of where I fish is electric only so I wanted to make sure I have enough juice to not get stranded and be able to focus on fishing.

[topwaterrob]

90% of where I fish is electric only so I wanted to make sure I have enough juice to not get stranded and be able to focus on fishing.

 

That makes sense as well....

[rippin-lips]

In hindsight I would of just bought 2 group 27's but I went with the 29 cause I was taking the boat out the day after I bought it. I knew it would be big enough for Deep Creek Lake which allows the use of outboards and that's where I was headed. Wasn't thinking about other places due to the excitement of buying a boat. I just wanted to get off the bank and fish. After getting used to it and using it a few times I wanted to make sure I'm plenty covered in the battery department. I've had the warning alarm sound on my fish finder 1 time previously when I had it set at 6 volts. Is it overkill now? Yes probably so but now I'm able to fish all day and not even have to give a second thought about the battery running dead. Tight lines

[Optima_Jim]

Not exactly understanding what you are meaning. Are you saying that I'm cutting into their life span or ?

That is the concern we generally express.  I's not often I come across someone who just started using mis-matched batteries in a parallel or series application, so I'd be interested in knowing how long they last for you.

 

Jim McIlvaine

eCare Manager, OPTIMA Batteries, Inc.

www.pinterest.com/optimabatteries