One Battery or 2 Battery

Ok here it goes

I am a newbie to this and first time owner of a boat, i have a 14ft grew boat and i am tranforming it into a fishing boat, also i am running a 40HP Johnson motor on it.

Want i want to know what will be best for me to run 2 batteries or just one , i will be running beside the motor, A trolling motor , bilge pump and a little stereo with few lights inside the boat . What i want to know if i need 2 batteries or just one and also how do i connect all the stuff any diagram or anything would be of a big help cause the season is almost here. I tought using seperate batteries one just for my johnson and the other ofr all accessories. and also i can see in most of the threads on this board people are saying Glass , i know what fiberglass is but glass ??

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

i will be running beside the motor, A trolling motor , bilge pump and a little stereo with few lights inside the boat .

Click to expand...

I'll provide you a spreadsheet that I built for myself; it might help you out. You can find it here: http://dl.dropbox.com/u/1459110/marine_battery_consumption.xls . Basically input the battery you want, input the list of devices and their amp rating and how many hours you plan to use them. It will tell you how long you have until the battery gets to 25% discharged, 50% discharged etc; assmuming my math was right.

That spreadsheet should help you come to your own conclusions about what you need. I don't know how much power a marine motor consumes so I cannot comment on if you need two batteries.

However, my west marine battery with 800 CCA, 1000 MCA, and 190 reserve minuites is super duper overkill for my boat; a 19' bow rider with a 135hp engine with a bilge running every few minuites 24 hours a day and seldom use of a depth/fish finder.

and also i can see in most of the threads on this board people are saying Glass , i know what fiberglass is but glass ??

Click to expand...

Would be referring to AGM batteries or 'Absorbed Glass Mat' batteries. They are going to cost you more than a starter battery but are generally deep cycle (good for accessory use) and if you have enough money big (good for cranking the engine). Another plus is that they cannot spill in the event of a rupture because they are not liquid batteries like the typcal starter battery.

I think the ideal suggestion is a starter battery for your main engine, and a deep cycle for all your acessories; however one AGM battery of sufficient size might be good enough. Really depends on your requirements.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

As soon as you add a trolling motor to the mix....in my opinion you need a 2nd battery. Go with a marine starting battery and a deep cycle battery.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

2nd battery if the first every runs out you will wish you had that second better safe than sorry. i would go with two in my boat i'm not running as much as you are and i run two battery's

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Thanks for the Info , i will try to figure your info out , i am a newbie , i will just put 1 light on the inside of the boat . I will use the light just to racks up the rod and putting the tackle box in order after a day of fishing at night the radio well only usd it when i get boring in the boat but my main objective is to used the trolling motor and fishfinder and the 40hp motor that is all and for the bilge pump only used it when i get water in the boat or after a rainny night. Also will it be good to have a little switch panel for the accessories??

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

for the assurance never leave home without a spare battery or at least a charger/jump start.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

I'd got 2 Batteries. Hope this helps.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Is there way i can size it bigger to be able to read it , i gues i will have to save it on the pc and then enlarge it??? But this diagram looks very cool .

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Yes right click and save it to your pc. Then open and zoom.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

When people on boating forums refer to a "glass" they are referring to a fiberglass boat. Generally NOT an AGM battery. You could also get buy with a siingle group 27 deep cycle or dual purpose battery. Folks will get all wrapped around the axle with this recommendation but the fact that your 40 HP Johnson can be rope started means you don't really need a second battery. If cost is not an issue, obviously a separate deep cycle battery for the troller and a starting battery for the motor is the way to go. No dual battery switches or ACR's here. Your alternator does not have enough output to keep two batteries charged. You need a portable or permanently installed on-board charger for the batteries.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Thanks Silvertip for your info , you are right for my motor it can be rope started but want to used the electric start on it before i used those weak arms of mine , lol. as soon i get my interior floor redone i will install the motor and try to find a picture or something to show me how to install the control box with the throttle and and steering cable to attach to motor.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

To Eagle.... I did save it on the pc but still got a hard time to read it even when i zoom it it is all blurry and if i un-zoom it it is too small. but dont take me wrong i really appreciate your effort to help me out.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Here try this one. It's a PDF and shoud be clear.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Thanks 2 Eagles this is way much better.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Sorry 2 Eagle but what do you mean by " Bus Bar "???

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Here is a photo of one. There are alot of different stills out there. But this will give you the idea.

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

I did this:
Compact battery backup and all kinds of other stuff too.
Provides jump starts for stranded boaters instead of connecting cables from boat to boat.
My Dos Centavos, Ed
Look for 20% discount coupons in magazines or the net.
http://www.harborfreight.com/5-in-1-portable-power-pack-96157.html

Re: One Batteryor 2 Battery

Re: One Batteryor 2 Battery

Strait said:

Thanks Silvertip for your info , you are right for my motor it can be rope started but want to used the electric start on it before i used those weak arms of mine , lol. as soon i get my interior floor redone i will install the motor and try to find a picture or something to show me how to install the control box with the throttle and and steering cable to attach to motor.

Click to expand...

I'm not suggesting you rope start the engine every time just because you have only one battery. What I mean is if you do run the battery down to the point where it won't start the engine, you can still rope start it. A group 27 battery will run your troller and any accessories for hours and still have enough power to start the engine. Obviously keeping an engine properly tuned and using the proper starting procedure means the engine doesn't have to crank for 10 minutes to start. For insurance a jump start unit is the simplest and cheapest.