Battery – how much is too much?

My boat started with a pair of 93SV’s. I never had a problem running these off my group 27 Interstate lead acid starting battery.
Last year I added a third 93SV which required also adding the GMS10 switch. I rolled the dice adding these two new devices to the starting battery and I had no issues.
Now this year I’m adding LiveScope which draws more than anything else.
I’m thinking I’m going to be pushing the envelope here… I really would prefer not to be stranded and not able to start my engine.
The easy answer would be to just add a dedicated electronics battery… but I have no idea where it could even fit in my boat. Space is at a premium. I looked up the draw for these devices, but the GLS10 has a pretty broad range. I’m just not sure where the rubber meets the road here.
Supposedly the X2 AGM batteries are built for this and have a 100% reserve. They state: “X2Power Marine batteries are two complete batteries in one – 100% starting and 100% reserve power to handle electronics.”
Maybe I just bite the bullet on one of those and give myself peace of mind..

What I read on their website stated that they have 30% more power than standard lead-acid batteries. That’s NOT “two complete batteries in one” as I would define it. It’s still one battery, and if it goes dead you have no battery. The price on their Group 27 is $449. Seems to me you’d be better off with one house battery and one starter battery, which is what I run in my Alumacraft 165 tiller. I don’t know what boat you’re running that you can’t find a way to fit another battery in, but I’d be looking to get rid of something to make room. You can never have too much battery power, but most of us have too much “stuff” in the boat that we don’t use.

If you’re going to spend $449 on and AGM battery, you might as well upgrade to a lithium version for $500.

Do you do any trolling? Have a kicker motor ? A kicker is a great piece of mind even if you only troll 4-5 times a year.

Ron wrote:

What I read on their website stated that they have 30% more power than standard lead-acid batteries. That’s NOT “two complete batteries in one” as I would define it. It’s still one battery, and if it goes dead you have no battery. The price on their Group 27 is $449.

I think they are saying it’s “two in one” because it’s dual purpose, both starting and deep cycle. And the 30% longer charge is probably the slower self discharge just because it’s AGM and that doesn’t matter at all really. Price is insane, a group 31 dual purpose AGM from interstate is $250.

“I really would prefer not to be stranded and not able to start my engine.”

I assume you have a trolling motor also?
What batteries do you have for that?
Jumper cables and/or being able to remove a battery form troller to main is pretty cheap starting insurance.

I would pick up a Noco or similiar device for back-up.

tim hurley wrote:

I would pick up a Noco or similiar device for back-up.

Great idea, jumper cables work too in a pinch as Mark stated.

tim hurley wrote:

I would pick up a Noco or similiar device for back-up.

I always have my noco with in the boat and on the ice in my fish house.

If space is an issue get the group 29 interstate…formally a group 31.

I had the exact setup you had, and when I added a livescope I mounted the lithium battery I got for ice fishing in the boat next to my trolling motor batteries and ran that dedicated for the livescope. I connected the on board charger and charger for the small lithium battery to a short extension chord splitter so I only plug one thing in to charge both.

isu22andy wrote:

Do you do any trolling? Have a kicker motor ? A kicker is a great piece of mind even if you only troll 4-5 times a year.

Next boat.

On this boat (Tracker V-175WT) I have a Force with a pair of group 27 AGMs running 24V. It pulls me around all day long without issue.
I do keep jumpers in the boat if the starter batt went dead… but a battery pack jumper would be a heck of a lot easier. I did bring one to Canada last year since we were so remote.

Since I really don’t know enough about that X2 to justify the price, I’m thinking I will search around to find a medium sized lithium (somewhere in that 50-60Ah area) and just make it fit somewhere to be my house battery. Amped has a 60Ah for $380 and Dakota has a 54 for $399. That Amped is only L*W*H: 7 3/4″ x 6 1/2″ x 6 5/8″. I can find somewhere for that…

I really don’t want to change out my Noco Genius 3 bank to a 4 bank. So maybe what I would do is move the leads from the Interstate over to this new lithium. The now dedicated cranking battery gets charged by the engine… but I could just throw a 1A or 2A trickle charger on it if it were sitting for a long time or something. But in general there shouldn’t be anything pulling off it as I would move the factory fuse block over to the lithium as well. I learned the hard way that the VesselView module leeches a decent amount of juice over time.

Perhaps with everything offloaded I could even downsize the cranking battery from a group 27 to a 24 (but match CCA) to make space in that compartment.

Ripjiggen wrote:

If space is an issue get the group 29 interstate…formally a group 31.

I believe you will still find Group 24, 27 and 31’s.

In a deep cycle yes not a cranking battery. Talking Interstate only.