Dual Batteries good idea or overkill?

[rbryant1492_mfb]

I was really thinking about if I neeed dual batteries on my boat. I have a charplotter, radio and big bilge pump. I really dont wanna be on the water and not be able to start the boat . So I decided to make the plunge and get a use the extra battery I have.

I really wonder how many people gave dual battery set ups?

 

[Monkaroo]

Re: Dual Batteries good idea or overkill?

Better safe than sorry . Better to have two and not need em , than need em and not have em . lol . I have an extra .

 

[burroak]

Re: Dual Batteries good idea or overkill?

I was really thinking about if I neeed dual batteries on my boat. I have a charplotter, radio and big bilge pump. I really dont wanna be on the water and not be able to start the boat . So I decided to make the plunge and get a use the extra battery I have.

I really wonder how many people gave dual battery set ups?

It's a great source of comfort to know that there is another battery onboard. A battery switch is highly recommended, but then.... that just gets you on the slippery slope. With more electrical capacity then comes the urge for more accessories.

 

[QC]

Re: Dual Batteries good idea or overkill?

Only way to fly . . . I mean float, or sumpin' like that.

 

[moterboat]

Re: Dual Batteries good idea or overkill?

I have the duels and batt switch on mine,would'nt feel safe without it..

 

[Boatist]

Re: Dual Batteries good idea or overkill?

Extra battery is a great idea but for me fishing unprotected water the first step is a Kicker motor that does not need a battery. I can get in with charged batery or a dead battery. I can get in if the main motor does not start. Dual Batteries and a Kicker is the way my boat is rigged. Never had to use the kicker or the second battery but if needed have both.

 

[Waffle]

Re: Dual Batteries good idea or overkill?

We went out today. The lake was almost deserted and the temps were 76 with a good breeze. Usually have to move about in order to cool down, but since the day was perfect we sat a bunch listening to the radio, playing with the depth finder the list goes on. Was sure nice just to be able to switch batteries than paddle.

 

[lncovert]

Re: Dual Batteries good idea or overkill?

I was thinking about getting a second battery.

Instead of using a switch is there a reason why you wouldn't just hook the batteries up in parallel (+ to + and - to -)? I guess in this way you could still run down both batteries running the radio all day, etc. and not know it. With the switch you could run down one battery, then realize your motor wouldn't crank, then you could flip the switch and have a new battery ready to go. But...is that the only reason to use a switch instead of hooking them up in parallel?

 

[Waffle]

Re: Dual Batteries good idea or overkill?

I think the main thing is if you have two batteries and don't have a switch, make sure you have tools to make the swap.

 

[Boatist]

Re: Dual Batteries good idea or overkill?

Hooking two batteries in parallel would be my last choice. First if you do it then both batteries need to be the same brand, same size, same age. Even then if one of the batteries has a bad cell it will run down both batteries.

instead mount the two batteries side by side and if the starting battery is dead switch the positive cables between batteries and start up.

 

[Zero Balance]

Re: Dual Batteries good idea or overkill?

I actually run three batts. 1 start 2 house. I run a small inverter at times and that extra house batt offers a bit more. In addition to the switch I have a combiner (VSR). This switch pretty much takes care of everything except water level and clean connections.

 

[slia67]

Re: Dual Batteries good idea or overkill?

Two batteries with an isoloator from BlueSea. Great piece of mind while you are anchored, playing in the water listening to your favorite tunes.

Doug

 

[BAYLINER185]

Re: Dual Batteries good idea or overkill?

I got stuck out on the lake one night when I bought new fishing lights. It was the 2ndtime out fishing from the new BAYLINER 185 w/ single batt.

well 3 hours latter CLICK CLICK CLICK, CLICK CLICK CLICK.....Oh Fu%K

Thanks God for some college guys and daddies boat LOL. Got a jump got back to the dock,.,...went and got a 2nd battery and charged the 1st batt and went back to the lake at 4 am.

3 days later hooked up a 2 bank isolater and the rest is history.

I now have a CIERA 2755 cruser and will no longer go out with the 185 so Im selling it with the dual set up.

The Cruser has 4 deep cycle batteries. Two on each side of the boat are parallel wired creating a 120 watt bank. This boat has a perko switch that is used to switch from bank 1 to bank 2 or ALL for charging by motor.

Also SHORE power has a dual bank charger and each bank has a line to charge them regaurdless of the perko switch position. Granted it wasnt wired right and I rewired it tonight and with any luck tomarrow the light will be green and my batteries ( banks) will be fully charged before I go out the 1st time with this big SOB!

I think all boats should have at least 2 batteries. I was going to do that 10 years ago on my last boat and never did and now that my 2 new boats are powered like that ill never be without a set up like that ever again!

 

[gunner1]

Re: Dual Batteries good idea or overkill?

My personal plan for the boat I'm redoing is buying the largest Optima I can find for the cranking side of things, then running two in parralelle for the rest of the electronics. The starting battery will be mounted in the stern and the supply batteries in the bow to try to evenly distribute the weight.

 

[Zero Balance]

Re: Dual Batteries good idea or overkill?

Another thing to consider is the alternator you'll have recharging your batts. Batteries in parrallel discharged can fry a 65amp alt. I upped the amperage on my alt to 94amp to prevent the aternator being over worked. I also bumped the hot wire to the batts to an 8ga.

 

[BAYLINER185]

Re: Dual Batteries good idea or overkill?

Zero Balance I just read your post and run pretty much that set up on ym boat.

I have two banks of marine batteries and a 65 amp alt. So what your saing is that if at least 2 of my batteries is run down to zip it can over work my altenator and burn it out let alone if all 4 batteries are down correct?

Ok here is what I have in the works, what do you think? I just bought 2 solar power battery chargers so that when Im not using the boat my batteries are beign maintained to full charge. I have a perko switch to turn off all the power on the boat and I do that when its not used so there is no load on the batteries. There will just be a nice flow of power to the batteries when Im not using her.

Also this will serve while I am out on the boat. You cant turn off the sun LOL so why not keep the batteries charging while Im using the boat and out crusing or just doing nothing but hanging out. Im thinking from reading your post that the load on the altenator will not be as much with some help from the solar power. ( the solar has a protection circut to keep power flowing one way and not back to the pannel when there is no sun to prevent battery drain)

Your thoughts...

 

[EJ3]

Re: Dual Batteries good idea or overkill?

I have 2 batteries and a battery switch. I like knowing I always have a backup plan for starting the motor. 1 battery I have dedicated to my OB. The other battery I use to power my bildge, lights, and trolling motor (and soon to be 12v aux outlet). The marine shop I visit frequently has told me that the battery switch can also be used to charge both batteries when underway (I hope they are correct!!). So I start up using the dedicated OB battery and turn the battery switch to both batteries once I am up and going.

 

[guy74]

Re: Dual Batteries good idea or overkill?

I just have one battery on board. I only boat on small lakes where I could row back to the ramp if I needed to. When we go out to bigger water we always travel in pairs. Don't have any battery loads other than marking and docking lights and engine starting. Can always rope start if I need to.

 

[achris]

Re: Dual Batteries good idea or overkill?

I was thinking about getting a second battery.

Instead of using a switch is there a reason why you wouldn't just hook the batteries up in parallel (+ to + and - to -)?

If you hook two batteries in parallel the differences in internal resistance sets up a circuit and the batteries end up draining each other. It doesn't happen in the space of a day, but it will happen within about a week. Once a lead-acid battery has been fully discharged it is pretty much toast.

Another thing to consider is the alternator you'll have recharging your batts. Batteries in parallel discharged can fry a 65amp alt.

Not true... The characteristics of an alternator are that the output is self limiting, by the resistance of the stator windings. If an alternator fried it was because of an internal fault, not an overload. All that should happen if the current load is more than the alternator can provide is that the battery/s start to discharge. Once the load is removed the alternator can then start to recharge the battery/s.

Chris.........

P.S. I have two HUGE(N70ZZ) batteries and a dual battery isolation switch in my boat. I can't get out and push.

 

[evolution6972]

Re: Dual Batteries good idea or overkill?

i was considering getting a second battery. I got one of those nifty jump boxes i still have to test it. But It should give plenty of juice to start if i kill my motor with my trolling motor. i am only trying to start a 40 hp yamaha.
But my main question is will i really hurt my deep cycle battery if i use it for starting. I did buy the biggest one walmart carried. My dad has always used his deep cycle battery for trolling and starting. Just trying to compare what he did to all your info.
thanks
D