12 volt batteries & trolling motor

[Olgrey]

My boat has a 12 volt trolling motor and the battery(1) does not last long in a wind. If I install a second 12 volt battery and connect them in parallel, positive to positive and negative to negative, is there any advantage to having a cutoff switch between them and only using the first one until it gets weak? I do not have any experience in this area. Thanks for any information!

[hairball]

The only advantages I can see are only having to recharge 1 battery if that's all that is used and, consequently, only having to replace one battery at a time if one is used more than the other.

[18'stratos]

You could use jumper cables to bridge them together, eleminating a switch therefore drawing from both batteries while in use. I dont know if there are any draw backs to getting more time on the water. I suggest doing a google search on it. I am not a battery pro either.

[12VoltMan]

There really shouldn't be any need to switch the second battery off. I also have a 12-volt trolling system and run two Optimas D34s in parallel and found that since the batteries aren't being drained as much each time I use them, they last a heck of a lot longer. The best way to tie your batteies together is to use short battery cables you can get from Autozone or Advanced Auto. The come in back and red so you'll always know quickley which is positive and which is negative. Plus the cables are already terminated.

[zimmy]

I had the same problem last year and ran mine together with short jumper cables and they last MUCH longer now-even on very windy days. Havent run down on me yet even if out on the water all day. You'll be happy once you put them together like everyone suggested...........

[kydonky]

From what I understand a battery will perform better, last longer with a slower discharge rate. So if a battery provides 100 amp hours and is discharged at a high rate you may only get 95 actual amp hours. If the discharge is a really slow rate you may get 105 amp hours.

So if you connect two batteries in parallel they will discharge at a slower rate than each would individually. If you seperate them the discharge rate will not decrease.

The answer should be to draw from both at the same time to decrease the individual discharge rate from each. Doing this will give you some benifit by reducing the discharge rate from each battery.

If you switch them from one to the other you really no longer have the parrallel concetion just have two batteries on a switch.

[coombro]

Been running two batteries paraller for three years now and haven't ran out of power since. More weight in the boat,but the advantages far out weigh that. I do, however have to charge each battery seperatly, but charging time is not as long. And I stay out on the rivers dusk to dawn not concerned about power at all. Try it you'll like it.

[Duayne]

I echo what has been said. Don't use a switch while in use. You want your batteries to discharge at the same rate at the same time. If you ran one battery down, then threw a switch, the charged battery would discharge into the spent battery as the potential will seek a common level the same as with water. The other option would be to disconnect from one after it is spent then connect to the other, but running them together is actually better.

I would charge each of them individually, though.

[zimmy]

Keep seeing "charge them individually".....any reason? I have mine charge at the same time with the trickle charger since i put them together and haven't seemed to harmed anything. Takes a while but has worked.
Just want to make sure i'm maybe not hurting my batteries??
thanks

[Panfish Man]

Mine are run in parallel and you just need to charge one. Both of them will charge equally, I have been doing it for a long time.

[raporter]

Mine are run in parallel and you just need to charge one. Both of them will charge equally, I have been doing it for a long time.

Same here.

[coombro]

never really gave it much tought, but if it works for you guys i,ll give it a try. thanks