Lithium...They're getting very popular but they have a real problem if you charge them below 32F. Charging them when cold can do permanent damage to them. There's new tech that allows some to be charged when cold but I don't know how widespread it is now or whether most automotive batteries have it now.
Who knows about using them in a boat?
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
As long as you don't run really long hard days or all weekend without charging you will be fine with one group 24 or better yet a group 27 marine cranking battery of whatever your budget allows. If you are going to run harder, longer, or add more electronics you may consider adding another battery, a deep cycle would be ideal. Unless you have a boatload of cash, I would avoid all the AGM and gel cell hype and just get a flooded lead acid type for around $100 bucks.
I run a group 24 starting battery for the motor, hooked up with an isolator is a group 27 dual purpose. 24 is isolated to start the motor only. 27 is to run electronics live well etc. That way if I spend a lot of time without running the motor it will still start.
Two yellow top group 31 optimas for trolling motor use only. Spendy but 16 + years old and going strong. Only run a charger when needed, never leave it hooked up otherwise, can overcharge cause problems.
I wouldn't over think this. I use a 29 starting battery on my motor and electronics, and have two 27' deep cycles for the trolling motor. 27's are all that fit in the battery compartment. The whole works is tied into a three bank automatic charger and when the boat goes in the shed, the cord is plugged in. All day, all week, all winter. Let the charger do its job.
When the batteries die, they die and you get new ones.
"Miss Jean Louise, stand up. Your father's passin.'"
It would be wise to have a matched pair of dual-purpose batteries linked by a (make-before-break) battery switch so you can reserve a fresh start battery that will not be drawn down by accessories, while being easy to combine them for charging off the main engine. There is no need to spend $400/battery. Flooded batteries provide the best bang for the buck.
"There's more to optics than meets the eye."--anon
"...most of us would be better off losing half a pound around the waist than half a pound on our rifle."--dhg
No battery expert. But I’ve tried to stay away from lead- acid batteries in boats. Most battery failure is caused from cells shorting together. Caused by segment in bottom of battery. Vibration and pounding of a boat increases this. Hasbeen
hasbeen (Better a has been than a never was!)
NRA Patron member Try to live your life where the preacher doesn't have to lie at your funeral
I prefer Naval batteries. They are much more even tempered.
But the Naval E7 to E9 models are often pretty heavy.
"...aspire to live quietly, and to mind your own affairs, and to work with your hands, as we instructed you, so that you may walk properly before outsiders and be dependent on no one." - Paul to the church in Thessalonica.
I like your set-up, and I'm personally geared towards redundancy on any critical system.
Question... Could that battery selector switch, or something similar be used to connect to a trolling motor battery for an emergency start. Would doing so complicate the charging system? Also, would the 1&2 switch position work with different style batteries? (deep cycle and starting)
I don't think it would work well for connecting the trolling motor battery in the situation you mention because the positive cables attach to the switch. To have the trolling motor battery backup you'd have to figure out a way to ground the trolling motor battery to the engine also. Mine are isolated from the boat's electrical system and I prefer that. I carry a tool kit on my boat, my plan if both starting batteries fail is to simply unhook the trolling motor batteries and swap one into starting battery's place. I've never had to do it but a minute with a 1/2" wrench will have the batteries swapped. I figure if I can't get it started with four batteries then I've got something else that's the problem.
The switch should work fine with different style batteries, it's just a basic isolation switch, nothing fancy. Those switches are the norm on smaller saltwater boats with two battery setups. Something used offshore needs a bit more redundancy than your average bass boat.
Four mainly starting a 115HP 4 stroke, what is the difference between a $100 battery and a $400 battery?
$300.
I am really surprised to see this response on Page 3. I would have guessed within the first few responses.
"...aspire to live quietly, and to mind your own affairs, and to work with your hands, as we instructed you, so that you may walk properly before outsiders and be dependent on no one." - Paul to the church in Thessalonica.
Four mainly starting a 115HP 4 stroke, what is the difference between a $100 battery and a $400 battery? This is a recreational boat, with a battery charger installed on boat. Boat also has a 9.8 kicker that has its own fuel line to main tank. It’s a pull start. One Garmin fish finder, and stereo.
The cheaper batteries have conventional, wet-cell construction. The more expensive batteries are typically AGM batteries, which are sealed and immobilize the acid in a fiberglass "sponge" to prevent spilling and leaking. AGM batteries are ideal for motorcycles, ATVs, and snowmobiles, where there is lots of vibration and the increased possibility of unusual positions (like rolling upside down). They are great in the marine application, as well, but I (personally) haven't found them worth the extra cost.
Originally Posted by RAS
Side bonus question:
Wouldn’t doubling up on two $100 batteries with a switch be better than one of the $400 batteries?
In my opinion, yes.
Originally Posted by RAS
And the double or nothing side bonus question:
What battery do you recommend for the above application?
I like the group 27 deep cycle batteries from Costco or Sam's Club. More info listed below:
My first boat had a single Yamaha F115, and I had a two-battery setup - one starting battery and one house battery for everything else. Instead of a 1-2-ALL battery switch, which I avoid, I had a 65A Blue Sea Add-a-Battery setup. The automatic charging relay is no-hassle way to go - just turn the battery switch on at the beginning of the trip, and turn it off at the end of the trip. Easy!
The charging relay makes sure both batteries charge, when the engine is running, and both batteries are isolated when the engine is off. You can run the house battery completely dead, and still have a fresh starting battery to get you home.
If your 115 outboard puts out more than 65A for charging, Blue Sea makes a 120A version, as well.
My current boat has twin outboards, and I run a 3-battery setup - one starting battery for each outboard and a single house battery. I use group 27 deep cycle batteries from Costco or Sam's Club. They have a high enough MCA rating to use as a starting battery, and they have enough storage capacity to function as a house battery. For $82 they are a bargain! I just replaced my two starting batteries for this season; had the old ones since 2016. They still worked fine, just replaced them as a preventative maintenance item. I replace my trailer bearings before they need it, as well. I figure I'd rather change them in my driveway than along the side of the road somewhere, with minimal tools and traffic whizzing by.
My Mercury 2010 115 hp four stroke came with one group 24 battery when my boat was new. Near the end of the season if I didn’t keep the battery charged cold starts became iffy.
I changed to a dual battery system with group 27 batteries and cold starting issues later in the season went away. Keep the terminals clean and connections tight and minimal problems.
3rd boat thread I've stayed away from in the past couple of weeks, even though I've made my living in the marine industry for the last 31 years. I learn so much here. 😁😁
