The boats that I have had previously were simple enough that one deep cycle battery ran everything. I bought my first bass boat last summer and didnt really pay too much attention at the time to familiarize myself with the wiring and battery connections too much but now that I have, Ive got some questions.

Theres 3 batteries.  2 deep cycles for the trolling motor an one battery for the motor and other electronics.  I verified that the 2 trolling motor batteries are indeed only connected to the trolling motor.  The battery that connects to the outboard motor, is also connected to all the electronics in the boat which includes the tilt/trim, all the gages, bilge pumps, livewell fill and aereator pumps,  flasher,  front and rear sonar.  The question is, should the battery that starts the outboard also be the one that runs all the electronics?  It seems to me that I am at risk if I am running livewell pumps and sonar units all day that I might run down the battery and get stuck.   Shouldnt the deep cycle batteries that run the trolling motor also run most of the electronics and pumps?  

Also.

The batteries are only 2 years old.  New June 2004.  They worked fine last year.  Fish all day.  I  kept them charged after each outing and charged them up fully before winter and didnt recharge them at all during the course of the winter.  Now I cant seem to get them to take a charge.  They worked fine last year.  Could they be that shot already that they wont take a charge?   Only 2 years old with not too heavy of useage?

thanks,

I have the same set up. Two trolling motor batteries running a 24 volt tm and a starting battery that runs all the accesories. That is the right set up. If you don't have one, the addition of an onboard charger would be a nice touch. Get a three bank and then all you'll have to do is plug your boat in at the end of the day and you should be good to go the next morning. As far as your batteries go, did you check the water level in them? I think 2-3 years is probably the normal life expectancy for trolling motor batteries. Perhaps yours have seen alot of use and they've reached the end of the trail. There have been some great threads about batteries, maintenance and set ups. A quick scroll through this section will bring you some informative reading. Ben is the master of boat electronics. Hopefully he'll weigh in and lend a hand.

Thanks.   Im glad the hookup is right.  I do have a charger but its a dual bank.  Maybe I will sell it and get  a triple.  I generally throw my portable charger on the motor and accessory battery which is sort of in-convenent.  I noticed last year that the red indicator lights on the dual bank charger that progressively show the charge level and then turn green when there fully charged always would not reach full charge and turn green on one battery.  I swithch the charger around and the problem followed the battery.  So maybe they have seen there better days.   I did check the water level in them last fall and all was well.   Less than 2 years seems a little less than I expect however for batery live based on the amount that I used it.  I only had the boat out 6 or 8 times last year.   The batteries were one year old when I got the boat.  The batteries are exide nautilis.  Im not sure how good of a battery the exides are.      

The batteries were ruined by not keeping them charged when not in use.  Can't blame the battery on that one.  

Your set up is normal and should be just fine. I always have a set of jumpers in the boat just in case I, or someone else, has trouble with the cranking motor. Year before last I knew my cranking motor was getting to its last legs but didn't replace it for last years maiden voyage. It fired up the motor and got me up the lake aways but it wouldn't crank the motor for my next run. Good old jumpers got me fired up from the TM batteries; back to the launch and off to buy a new cranking battery.

A 3 bank onboard would be handy but you can get by without it by using your portable charger. Don't rely on your big motors alternator to keep the cranking battery charged up. Unless you run at speed a lot it won't. Charge all 3 as soon as you get home!

During the winter you should either check the state of charge or charge the batteries from time to time. My boat is garaged and I charge every month. This is where the 3 bank is real handy.

I have had a bass type boat for more than 30 years and 90% of the boat problems have had todo with electricity. Never serious but still a nuisance.

Wire connections that shake loose, trolling motor plugs that fail. Get yourself a decent voltmeter so you can fix most of the little problems. I carry an extra trolling motor plug in my boat as a just-in-case. I've never needed it but it is there if the need arises. Unless I have neglected the batteries I find they can last 5 years.

Getting to the batteries to check and top off water levels is a real pain in my boat almost requiring removing the batteries. I solved this about 3 years ago buy getting one of those automotive water dispensers that lets the water flow into the battery until the water reaches the full point, then it shuts off. I had to go to a few auto supply shops to find one but the $14 or $15 was worth it for convenience.