New boat guy battery question

[showstoppr88]

So I got a boat with no battery in it. What do I get? It's got a mercruiser 5.7 in it but will also run tilt pump, lights, stereo...etc. do I run two batteries? No clue where to start any advice would be great.

 

[grtomboy]

Def two. One for starting and one for deep cycle. I keep mine on a battery tender / maintainer. Best $40 I ever did spend

 

[tpenfield]

If your boat is currently set up for two batteries, then you can get a regular marine battery (which is a hybrid of a 'starting' battery and a 'deep cycle' battery) along with a deep cycle battery, as mentioned. If the boat is currently set up for only one battery, then just get a marine battery.

 

[Scott Danforth]

group 24 as a minimum, preferably a group 27

 

[savetexomabeaches]

I run duel marine batteries in mine with a perko switch.

 

[showstoppr88]

See thats where I dont get it, I get you have a starter battery then you have a deep cycle for pretty much anything else. Does the alternator just charge them both up at the same time? Then if you have that round switch I have been seeing where you can pick bat 1, 2, both. What makes you ever pick the "both" option? What are the steps if starter is on bat 1 do you start the boat with that switch and then flip it to bat 2 while your fing around on the boat?

 

[tpenfield]

Does your boat currently have the Perko (round) battery selection switch?

If so, you can charge them at the same time with the 'Both' setting. If you notice the switch pattern goes from 1 - both - 2. so, as you turn the switch, there is always at least on battery connected, and as you transition for 1 -> 2 both batteries are connected in between.

I use general marine batteries for both, so I am not all that particular on which battery I use while anchored, etc.

 

[showstoppr88]

My boat (used) has nothing at the moment haha the guy took the battery which was originally a one battery system.

 

[showstoppr88]

I thought I was seeing there could be an "issue" charging both batteries on one system? So whats the drawback to just using a "marine" or hybrid battery and leaving both batteries to the "Both" setting 100% of the time?

 

[showstoppr88]

Also do you keep that round switch near the captains chair or in the back engine compartment?

 

[tpenfield]

I am not much of a battery connoisseur . . some folks like having both the starter battery and the deep-cycle, and charging them separately. The primary thing is to always be able to start the boat for the return trip home. So, if you are anchored for a long time, using power for stereo, trolling motor, etc., a deep cycle battery will give you the most duration.

Then when it is time to go home, you know your other battery has not been drained down, so you can switch to that battery to get the engine started.

I keep the switch right where the manufacturer installed it, which is right next to the beer cooler Very practical design IMO.

​It sounds like you are considering an upgrade to dual batteries ?

 

[showstoppr88]

Yep exactly, I'm in this deep why not make this right? So where is your beer cooler located? haha.

 

[savetexomabeaches]

Because leaving both batteries set to both, if you park, shut off engine, now you're draining both batteries, and both batteries are trying to equalize each other.. But, if you park, and go to your 2nd battery... you can run that down thing dead, and when you're ready to go, switch to 1 to start, then switch to 2 to start changing the dead battery

 

[showstoppr88]

or should it be at "both" while riding?

 

[icwingman]

So I got a boat with no battery in it. What do I get? It's got a mercruiser 5.7 in it but will also run tilt pump, lights, stereo...etc. do I run two batteries? No clue where to start any advice would be great.

Get 2 deep cycle battery's at Walmart biggest amps they. Then get a cheap dual
Battery switch

 

[Silverbullet555]

I run two starting batteries because I'm odd like that. Both of my batteries are group 31 with 1140 cranking amps and 175 minutes of reserve capacity. I switch the batteries each year which is why I run 2 of the same. I have a big stereo and have never killed my house battery.

If you want to do it right, add an ACR that will automatically combine your batteries when charging. That way you don't have to remember to put the switch on both. Blue sea makes a kit yo do it.

 

[redneck joe]

I keep mine on a battery tender / maintainer. Best $40 I ever did spend

solar?

 

[redneck joe]

what is this 'group' number yall are talking about?

 

[showstoppr88]

Does anyone use a starter batter and then a deep cycle? (speed boat)

 

[grtomboy]

solar?

Not solar. I wish! Never occured to me until you mentioned it just now. But I like the reliability of a cord, since my boat sits on a trailer at home rather than in the water.
And yes, I have a starter battery as well as a deep cycle marine.