Run two deep cells or do I have options?

Ok, I do not need a battery for my motor. So my deep cell is up front for my trolling motor. Now, I am adding the depth finder, bow and stern lights, two 8" led strips for the few times I go night fishing, bilge pump and aerator for the livewell. Can I add a small lawnmore/jetski type batter to run the lights, bilge and aerator? I dont night fish often, but would like to get 4 hours or so when I feel the need, so the lights would be running off of it. The livewell would only be ran from time to time because I fish a small tournament on Sunday mornings for 4 hours. Bilge only used in an emergency and I know the depth finder uses little to nothing. So, can I get away with a small battery like that? I didn't entertain the thought of running off of one battery. Is that an option? Or should I go with another Deep cell. Thanks in advance for the insight!

You need to do an analysis of your battery needs. Take the aperage draw of the devices that you are going to be running and determine how many amp hours of power you are going to need. For example, if your trolling motor draws 30 amps(that is an example) and you are going to run it for 5 hours a day, then it will use 150 amp hours of battery power. If you have a light that draws 5 amps and you run it for 30 minutes, then you will use 2.5 amp hours of power. It's pretty simple once you understand what you are doing. Once you know how much power you are going to consume, you can match that witha battery( or batteries) with enough capacity to get you through the day. A group 24 battey will hold about 85 amp hours of power, a group 27, around 105 amp hours. You don't want to regularly draw your battery down below 50%. To do so on a regular basis will shorten the life of the battery and even though you recharge every time you use it, that will not stop the deterioration of the battery's cells. If when you add up your current requirements you find that you are going to use more than 50% of your battery's capacity, then you need to add a second battery.

When shopping for a battery, don't get stuck by a slick salesman selling you a "dual purpose" battery. These are what Walmart and Auto Zone sell. They are basically starting batteries with a little bit heavier plates, and will handle light loads like a couple of lights or a stereo, but they will not hold up under the constant discharging and recharging needed if you are running a trolling motor. You need to use actual Deep Cycle batteries.

1st off, don't hook your FF up to the TM battery, usually will create interference on the FF. A small lawnmower batt will run a FF for several trips, if the lights are LED, then you might get away with the small lawnmower batt for all your additions. You could wire the bilge pump up to the TM batt since hopefully you won't be using it much, if any. If you have the room/$$, etc., another deep cell will work just fine for all of that.

I am in the Same boat " HA ! " any ways but my motor does use a battery and i am on the water 6,7 ,8+ hours at a time and i figure if i catch a nice keeper firs thing thing in a tournament then im going to need to run the pump and want not all day as well as im going to be moving from spot to spot so i think i am going to go with 2 deep cells cuz 1 for the trolling motor and fish finder up front and one in the back for everything else, and i was looking into on board chargers but i have NO idea how they work and if it is even worth it to get one

You should be able to get away with a small lawn mower size battery, only the livewell pump will draw any substantial current and you could put that on a timer to conserve current. I would suggest an AGM battery, https://www.batterymart.com/c-12-volt-big-crank.html ,they last longer (lifetime wise) and never need maintenance. Use a 2 amp floater / maintainer to keep it charged, maybe $20.

I run my trolling motor on my small AGM battery.

Tim

on board chargers are worth the $$ imo, never have to go looking for it, they are designed to charge marine batteries properly, but the owner still has to do the proper maint such as water levels, charge the batts up as soon as you get home, (dont wait till next friday night to charge 'em up). With you having one batt up front and one in the back, the wiring is bit more involved, but still the same. Just get a 2 bank one since you have two batts.

well this is what i am using now
https://www.walmart.com/ip/Schumacher-XC103-100-30-12-2-Amp-Battery-Charger/15140198
and i do as soon as i get home i charge it right up ! and i only have 1 now but am going to be getting the second soon.

i have been looking into this but have o idea about on board chargers,Minn Kota On Board Battery Charger 2100

what are your thought/ positives and negatives on the on board charger

If your budget allows get an on-board charger, you will never regret it. This is my 3 bank setup, 2 deep cycle and 1 starter battery.

Be careful hooking your aerator up to your starting battery...my dads Ranger is hooked up that way and we ran the starting battery dead one day in a tourney. Found fish early in the morning and ran the pump all day with starting the engine only a few times...luckily we had jumper cable and jumped it from the trolling motor batteries.