Battery Setup

[ComancheC]

Hello guys,
A new boater here with a couple questions.
1. I have a 1990 481 Comanche, with a 24v Motorguide and Hummingbird 898c, and smaller unit up front. Could someone give me a few selections as far as the best battery set up I could get for the boat? Also, it is stored for 3-4 months out of the year. I need both trolling batteries and a cranking battery. What can I run in the boat? What is the more cost effective route?
2. How do I maintain battery life while storing for 3 months?
Tight lines,

Tyler

[whatroads]

There are lots of threads about battery choices and as many opinions. I'll keep my reply generic. I use 2 group 27 deep cycle marine grade batteries for the trolling motor. Even with all day use, I've never needed more trolling motor battery. I use a group 24 cranking battery for the motor and all electronics. Keep in mind the cranking battery is charged by the outboard motor.

I have to store my boat outside and it does not get used from late Nov to early March. I always pull all three batteries and store them in my garage. I check the charge every 3-4 weeks and re-charge them as necessary, (I used a digital volt meter). It's a good idea, before you pull your batteries the first time, to take detailed pictures of their setup. And, tag all wires. Makes re-installation a no guess process

[jc2bg]

You do not say which engine you have, or what year the engine is. I point this out because many of the engines produced in the past 10 years require 800 to 1000 cold cranking amps to start. A series 24 cranking battery might be beneath this threshold for newer engines, and even with an older engine might still be on the low side for reserve capacity when running multiple locators and livewell pumps. This issue would be even worse if at some time you upgraded to larger electronic units. It is standard these days for bass boats to come with 27 series cranking batteries, and on the larger, tournament rigs 31 series batteries are preferred [if not always used]. Otherwise, I agree with the tips that whatroads has provided.

[greenfshrmn]

I had a 482 Ranger for many years and agree with what whatroads said. However, if you live in the warmer part of the country I wouldn't bother bringing the batteries indoors.

[lpugh]

What motor do you have on the back, this is important info needed

[ComancheC]

Good morning,
the motor I have is the original 1990 Mercury Blackmax 175.

[ComancheC]

Good morning,
I have the original motor, a 1990 Mercury Blackmax 175. Thanks!

[RANGER487]

I use the Walmart 29 series for cranking on my 487 for 200 EFI and 3 of the 27 series for my trolling motor. I usually charge 2 to 3 times in a 3 month period just to top them of.

[DrewFlu33]

That motor, being a Mercury with a stator (as opposed to an alternator), is NOT recommended for use with AGM batteries. Some have done it without issue and have compelling reasons for why they don't worry about it, others have had stators go shortly after trying an AGM. This is one where I err on the side of caution and use a lead acid as a cranking battery.

The advice I've always heard and that never lets me down is to go with the biggest batteries you can fit. I have a 481vs that I have set up for a 36 volt trolling motor. Assuming the bilge is not different on yours, you can fit up to 4 group 31 (or group 29, same thing) batteries back there if you want. If you're sticking with a 24 volt trolling motor, I'd still suggest going with group 29/31 batteries for cranking and trolling motor. Personally, I like East Penn batteries (over Johnson Controls and Exide, basically the only other two options you would have). The best bang for the buck there is via Sam's Club Duracell branded ones - they're identical to Dekas but just have different stickers and cost less. 2 group 31 deep cycles for the trolling motor should work very well for you. I run their group 31 commercial as my cranking battery. Don't let "commercial" fool you, they work awesome on boats and have a lot of power. With that combo, you're out the door and good to go for right at $300.

You didn't ask, but just to be sure: Everything gets hooked up to the cranking battery except the trolling motor, and the trolling motor is the only thing hooked up to the trolling batteries. This avoids issues.

As far as battery life while in storage, assuming this is winter storage, even with the moderate cold in Alabama (the colder it is, the less batteries discharge while in storage so us northerners have an advantage there) you will be fine for that time if you simply charge the batteries fully (after checking water levels), and unhook EVERYTHING from them. If you leave things hooked up you will have issues and would need to be concerned about charging them.

Here's some info from the Battery University re: discharge while in storage at different temps. As long as they don't discharge down toward 50%, you're safe; obviously just charge them up when you get your boat out of storage:

[ComancheC]

Thank you so much for the help! I really appreciate it sir.

[LTZ25]

I can't believe someone hasn't started a business where they will lease you a battery package , anything you want for 3 years of payments and then start over with fresh batteries .

[DrewFlu33]

One additional thing: Since that motor has a stator and no alternator, the amount of charging that your outboard does is really only enough to maintain it while it's running. It's not going to gain any appreciable charge "back" when running around, so definitely plan to charge the cranking battery each time you come off the water. Assuming you're sticking with the 24 volt trolling motor, a 3 bank onboard charger is a good idea if you don't have one already.

[RazorCat]

Hello guys,
A new boater here with a couple questions.
1. I have a 1990 481 Comanche, with a 24v Motorguide and Hummingbird 898c, and smaller unit up front. Could someone give me a few selections as far as the best battery set up I could get for the boat? Also, it is stored for 3-4 months out of the year. I need both trolling batteries and a cranking battery. What can I run in the boat? What is the more cost effective route?
2. How do I maintain battery life while storing for 3 months?
Tight lines,

Tyler

Buy AGM batteries. Fully charge them before storing. I store our pontoon from November until March outside. The Duracell AGM (27M) batteries hasn't missed a beat on first startup in 3 seasons.
IF I read correctly, the 481 is an 18 foot boat with up to a 175. Similar in size/HP to my Sabre FTD. I run two 34 series AGM batteries on my 24 volt MG Tour, and a 31 series AGM for electronics and cranking. They haven't failed me yet, and the Optima 34 series TM batteries will be 10 years old in March, 2020. The cranker is still strong at 4+ years old. The Duracell AGMs were still on sale at same this past week. $20.00 off. A bargain.