I should add a 2nd battery...

[guy48065]

This can be either very simple or it can get involved.
Without getting into the depths of yacht battery banks & charging systems...
How have you added a 2nd battery to your small-medium boat, and did you also add the means to automatically keep it charged?

 

[Pmt133]

I've never found a need to on my 19. Mainly because I don't have the room or want to lug around a second battery and I don't have very many electronics to drain said battery.

That being said the 330 has 4 batteries. We added a dedicated house battery, pulled all house loads off the starting battery and wired it in with a bluesea ACR. With the improvements made in the last 15 years I'd probably use a dc-dc converter instead to charge while running. On board charging is wired to it as well and we used the Volvo isolation relays that are tied to ignition to isolate the ACR while charging on the house charger so the load sensing and smart charging work properly.

For a smaller boat, add whatever loads you want to the battery and just wire in the dc-dc charger. Maybe a combine switch if you want to be able to use extra juice in an emergency.

The worst part was eliminating the rats nest of crappy wiring wellcraft has been known for forever. You've never seen so may crossed connections in a distribution block...

 

[tpenfield]

Generally 2 ways of adding an additional battery to a single battery set-up:

1) Directly connected in parallel

2) Selectable via A/B/Both switch (aka Perko switch)

Option #2 is preferred as you can run stuff on 1 battery and keep the other in reserve. While underway, you can be charging both batteries.

In terms of charging . . . if the existing charging systems (alternator, shore power, solar, etc.) are capable of handling an additional battery, so be it. Otherwise, you might need to upgrade.

 

[jlh3rd]

is a 24' pontoon considered a medium boat?
anyway, I added a second battery, a selector and an acr. It was simple, and appears to be working well after 3+ years.
Also cleaned up the rats nest factory wiring in the console.

 

[arks]

My 14’ jonboat has a small lawn tractor battery for starting.
I added a bow mounted trolling motor a few years back and installed a group 31 battery up there to run it.
Worked fine but batteries weren’t connected.
Last year I ran a pair of 6 gauge wires to a Perko on/ off switch. This enables me to use the big battery to start the outboard if needed. Pretty simple. No onboard charger; I boost the batteries from my home charger before using.

 

[dingbat]

Added a second battery with Blue Seas “add a battery” kit.

Went with two (2) FLA deep cycle batteries for increased storage and durability related to DoD issues.

Put in a lot of runtime. Typically make it a month before I need to supplement with external charging.

 

[cyclops222]

Are you doing the complete installation personally ? Or just wanting enough information to order someone else to do it your way ?

 

[Lou C]

I added the dual battery system with the switch about 20 years ago because my boat has always been moored and if heavy rains & storms occur you want to make sure that bilge pump will be powered and still be able to start the engine to then recharge the battery that may have been depleted from running the bilge pump.

 

[cyclops222]

Excellent logic. There is NO DIFFERENCE going to a boat after enough rain has run down the Starting Battery to 0 volts. Moored out or at a dock.
Same dragging around another charged up battery to use while the dead battery is SAFELY charged up with a full sized 120 vac unit for 2 days.

 

[Lou C]

It’s rare but when that’s happened what I’ve done is start on the battery that wasn’t used for the bilge pump; then switch charging to both, run it that way for about an hr, then switch to the battery that was used running the bilge pump to make sure it gets as fully charged as possible. In marine use with small boats we are limited to alternators that don’t put out that much current and also limited run time. Think about it if you charge a partially discharged battery with a home charge @ 10 amps it takes like 5-8 hrs to really fully charge it. So I also alternate use of the batteries. #1 on odd # days & #2 on even # days….
It takes some thought but has worked well for me for 20 years….

 

[guy48065]

I added the dual battery system with the switch about 20 years ago because my boat has always been moored and if heavy rains & storms occur you want to make sure that bilge pump will be powered and still be able to start the engine to then recharge the battery that may have been depleted from running the bilge pump.

THIS is my situation.
Boat is tied to my dock 200 feet away and has a 1 year old starting battery. No starting problems in the 2 weeks I've owned it. My only concern is the bilge pump running the battery down.

The #2 battery could probably be the smallest starting battery available. Or a lithium. Or maybe i should just stow a lithium boost pack. I've had good luck with those in the past starting ANYTHING I attach it to. I keep one in each of my cars because they're both over 10 years old.

 

[Pmt133]

Don't keep the jump pack in the boat. They are good though. I've had to put out a few fires from them getting too warm in someone's car or boat though

 

[guy48065]

I have always run 2 batteries in my pontoon, with a Perko switch. I've never needed the #2.
I'm always wondering IF I ever need it will it be ready. I charge & test it fully in the spring before putting it in the boat, then ignore it the rest of the season.
I don't have shore power at my dock.

 

[guy48065]

Don't keep the jump pack in the boat. They are good though. I've had to put out a few fires from them getting too warm in someone's car or boat though

I've had one in the back of my suvs for at least 10 years with no issues. I know about the concerns but have had no storage problems.

 

[Pmt133]

I've had one in the back of my suvs for at least 10 years with no issues. I know about the concerns but have had no storage problems.

Thats what they said too. Just saying is all. Put them in like an ammo box or a flame pouch and then its fine. (What I do with mine)

 

[Lou C]

THIS is my situation.
Boat is tied to my dock 200 feet away and has a 1 year old starting battery. No starting problems in the 2 weeks I've owned it. My only concern is the bilge pump running the battery down.

The #2 battery could probably be the smallest starting battery available. Or a lithium. Or maybe i should just stow a lithium boost pack. I've had good luck with those in the past starting ANYTHING I attach it to. I keep one in each of my cars because they're both over 10 years old.

It’s good to have the system installed; not a lot of work, but user error can get in the way….you can get nice new cables made up & do it yourself. Blue Seas makes a nice switch as does Cole Hersee.
Never leave the boat with the switch on Both because if one battery fails it will suck the juice out of the other and then you’ll have two dead batteries!
Also be sure to alternate use of the batteries to keep both charge.
Never turn the switch to off with the engine running it will blow the diodes in the alternator.
The bilge pump should be connected to one of the batteries not thru the switch that way you can turn the switch to off when leaving the boat but the bilge pump will be powered.

 

[jlh3rd]

I have always run 2 batteries in my pontoon, with a Perko switch. I've never needed the #2.
I'm always wondering IF I ever need it will it be ready. I charge & test it fully in the spring before putting it in the boat, then ignore it the rest of the season.
I don't have shore power at my dock.

I have the acr which sends a charge to the battery that's weakest. I also have a 2 flat solar chargers mounted on the rear left of the pontoon, one for each battery. No way to tell if they actually make a difference, but I've owned the boat since 2016-17 and haven't had a dead battery problem yet.
I also at the first and last of the season use an automatic charger/maintainer/ de-sulfating(so says)/ reconditioning (so says) charger.

 

[airshot]

If the bilge pump keeps running the battery down, perhaps a better cover is needed to keep the water out. My 140 ah lifepo4 battery will run for many days without running down. Solve the problem rather than patching with bandaids, so it appears...

 

[StewartL]

I added a second battery with a simple battery switch 1-2-Both-Off and a dual-bank charger. The switch lets me choose which battery to use or charge, and the charger keeps both topped up when plugged into shore power. No fancy isolators or complex wiring just reliable, straightforward power.

 

[Lou C]

If the bilge pump keeps running the battery down, perhaps a better cover is needed to keep the water out. My 140 ah lifepo4 battery will run for many days without running down. Solve the problem rather than patching with bandaids, so it appears...

Agreed I have good covers & always used them even though it’s a pain but the boat isn’t self bailing so you just have to use em. And no matter what they all leak some!