So let’s talk batteries…

[rgsauger]

I have had a pair of group 27 marine batteries from Walmart in my boat since 2015. I keep them on a battery tender and always keep them fresh. They have always worked perfectly until last Saturday, when they didn’t. It cranked up perfectly and ran great and voltage was around 14.4 V. I ran for about 25 minutes and shut it down. Went to crank it up and it would not turn the motor over. I cleaned the contacts and reassembled to no avail. I then said to myself, “self, no big deal. Just swap the two batteries.” So I did. To no avail. Both of them were shot. WTH???

I know that some of you guys are going to say that I should be damn thankful to have gotten seven years out of a pair of batteries, and I am, but I swear I had absolutely zero advanced notice that these batteries would fail miserably in a matter of minutes. It was in the 90s temperature when they failed

so this brings me to the place where I need to buy batteries. I prefer to run two batteries and not three in my boat. One of them cranks the motor and then I have a dedicated circuit for the trolling motor that is 24 V with the two work batteries wired in series.

I have successfully run the Optima batteries in my jeep CJ with a big winch and also in an Allison drag boat. I currently have a yellow top optima in my jeep and it runs great. I’ve been considering putting a pair of Optima‘s in the boat. I also see the advancements in technology and weight savings for lithium batteries. Very attractive but I will not spend $1,000 on a pair of batteries!

My big motor needs 12v and my Trolling Motor needs 24. Honestly, I do not run my trolling motor very much. What ideas do people have for this? The idea of weight savings is very attractive as my hull is sensitive to it.

thoughts?

[Fishwhisper]

What motor do you have?

[OnPad]

Keep on keeping on, 7 years is dang good!
If you did alot of trolling I would say, dedicate a set, as pulling off a start battery is hard on it. Sealed bat would be nice, but at that point you would be at half the price of lipo/life.
I have a single 12v in my ltv, used for engine and troller. For the same reasons as you.

[Dave S]

12 rem.....24......How do ya have them wired? .... bats with diff ernt needs and chargin?........ Yes I kow......Blown the ???? and put the cure first.......;

[Dave S]

Ya Mixed the Battts????? Deep an Charge/ start????

[OnPad]

Walmart marine start/troll, wired in series for troller, and pulling 12v off of one for engine. The same way you would
wire a multi bank charger on a bass boat. His start battery is going to be higher voltage than trolling battery, and a bit more stress on the voltage regulator on engine. But he's saving weight, and has enough money for beer at end of the day.
I figured this one would be controversial.

[rgsauger]

What motor do you have?

V200 Merc

[XstreamVking]

I like the 1200 oddesseys for trolling get two for troller and use a big single 1000 amp start for the engine. I know just two batts but this is the best setup IMO

[Capt j]

You should never use the starting battery as part of your trolling motor battery combo. EVER. That being said. Get a Dakota 24v 50 amp lithium battery for your TM, 32lbs and a single battery. Get a Dakota 12v60 amp dual purpose lithium battery 1000 cca's for your engine......16lbs.........

[rgsauger]

I just checked the price of those Dakota batteries. My damn boat value would go up 25% if I added them! Sorry but $1500 worth of batteries ain’t happening. I might just break down and put those same damn Walmart batteries back in, heavy or not. $150 each.

[XstreamVking]

Sometimes low tech and simple works just as well as the hi-tech expensive in actual use.

[lbhsbz]

The best way to do it would be to run the batteries in parallel for starting the engine and then switch them to series for the trolling motor...that way both are subject to the exact same circumstances all the time.

7 years is a good run. I prefer conventional lead acid batteries because they'll cheap and they work, but I prefer Deka/East Penn manufactured...not sure where walmart is getting there's these days.

[rgsauger]

So on a 90 Merc with 16 amp stuff, can I run an Optima or other AGM battery? If not, why not?

[OnPad]

Another controversial question.
I vote yes.
The alternate school of thought, will say they have the possibility of overcharging.
Mercury won't endorse the new lipo/life batterys, for the same fear. Even though they have built in circuit board protection, and people are using them successfully.

[4Speed]

Still running the Blue top Optima that Jack installed in my STV when he built it in 2010. I do remove it every fall and place in the cellar on a piece of wood. I place it on the trickle charger over night monthly (I don't leave it on trickle for days/weeks/months). I use S/S nylon lock nuts with washers on the studs (not the posts) with the starting lugs/ cables going on first with a little dielectric grease.