Want a Second/Backup Battery for Pontoon Boat

[Sierra048]

My wife and I bought a small pontoon boat on year end clearance to take advantage of the beautiful, large reservoir we have access to. It came with an Interstate 1000 CCA marine starting battery. I ordered a Blue Sea Systems battery switch to facilitate and extra battery. Boat has a Yamaha 60hp which is it's maximum rating. Other than starting, and using the stereo while out cruising or at anchor, there shouldn't be much more demand for power. One battery might be all I need but for the cost of the switch and an additional battery, I'd feel a lot better especially if spending a long day out on the water.

My question is, what kind of battery should I get for the backup? Another 1000 CCA marine battery? An automotive deep cycle battery? Or, does it really matter for it's intended purpose. Walmart has a 1000 CCA marine battery for $74.99. A 650 CCA deep cycle automobile battery for not much more. Any ideas or suggestions. Thanks.

 

[WobblyElvis]

Any battery will serve your purpose, but it must be maintained. A trickle charge now and then and occasional use will help it last a long time. If you are going to be moving it often, a good carry handle is in order. Go for the cheapest.

 

[dlundblad]

Buy another of what you have spec/ marine battery wise. Obviously, brand doesn't matter.

Switch it up when you use it. Start the boat on 1, then 2, then both, alternate with accessory use etc. to exercise the batteries.

At the end of the day, it's nice knowing the battery you're drawing from to run the stereo/ anchor lights aren't what you'll need to start the engine.

 

[krismoriah72]

For the second battery wouldnt you want one with high amp hours? vs looking at CCAs?

Put the stereo on the second battery with the higher amp hours?

 

[bullwinkle]

If you want a battery for running your stereo, lights at night anchor, etc.-a deep cycle is the best way to go, it can be run dead or nearly dead and last longer. Also, an isolator is better than a switch, that way the engine alternator can recharge both batteries. Although the outboards I've had that had charging coils under the flywheel could barely charge one battery-a decent sized solar panel would probably be better at charging the auxiliary one when there's no shore power available.

 

[Sierra048]

Originally Posted By: bullwinkle
If you want a battery for running your stereo, lights at night anchor, etc.-a deep cycle is the best way to go, it can be run dead or nearly dead and last longer. Also, an isolator is better than a switch, that way the engine alternator can recharge both batteries. Although the outboards I've had that had charging coils under the flywheel could barely charge one battery-a decent sized solar panel would probably be better at charging the auxiliary one when there's no shore power available.



Sorry, I misqoted. The Interstate battery I referenced earlier has 1000 MCA, and 800 CCA.

Bullwinkle,

The battery switch I ordered off of Amazon has four positions, Bat 1, Bat 2, Bat 1&2, and off. Wouldn't both batteries be recharching in the Bat 1&2 position? Or are you thinking there might not be enough output to charge both at the same time. Years ago when I lived on the Florida West Coast I had a larger boat with a much larger engine for fishing offshore. It came with dual batteries and a switch so I never had to deal with it, ie. Installation. It was so long ago I don't remember what kind of batteries or how the boat was wired.

 

[Pajero]

My favorite is Odyssey Battery! They are expensive, but I go to far remote places on land. I would apply the same logic to water. But, that's a personal preference. Prior to Odyssey I had a Sears Platinum battery, but it was discontinued. I've heard others commend Duralast batteries.

Good luck battery hunting!


Respectfully,

Pajero!

 

[Dorian]

The Odyssey batteries are great. It might be a good idea to put the new one in place of the primary battery and use the old one as the backup. We typically have a back up as well. Although a good marine battery will slowly increase in voltage as it sits for a few hours, you can't tell when they are going bad until it is too late! Enjoy your new ride. The Yamaha 60 will treat you well. They are absolutely bulletproof. Just be sure to not be that one family that does not wave to anyone else on the water. Nobody like them. Also, standing up while driving the boat is a sure sign of an inexperienced driver. Lol.

 

[EdwardC]

Originally Posted By: Sierra048
Originally Posted By: bullwinkle
If you want a battery for running your stereo, lights at night anchor, etc.-a deep cycle is the best way to go, it can be run dead or nearly dead and last longer. Also, an isolator is better than a switch, that way the engine alternator can recharge both batteries. Although the outboards I've had that had charging coils under the flywheel could barely charge one battery-a decent sized solar panel would probably be better at charging the auxiliary one when there's no shore power available.



Sorry, I misqoted. The Interstate battery I referenced earlier has 1000 MCA, and 800 CCA.

Bullwinkle,

The battery switch I ordered off of Amazon has four positions, Bat 1, Bat 2, Bat 1&2, and off. Wouldn't both batteries be recharching in the Bat 1&2 position? Or are you thinking there might not be enough output to charge both at the same time. Years ago when I lived on the Florida West Coast I had a larger boat with a much larger engine for fishing offshore. It came with dual batteries and a switch so I never had to deal with it, ie. Installation. It was so long ago I don't remember what kind of batteries or how the boat was wired.


I think the concern is that when you have it in Bat 1&2 position, it'll charge both batteries, but will also draw from both. An isolator would allow both to charge, but your accessories can be connected to the isolated battery where if it was totally drained, the first battery would still be fine. Like someone else mentioned, a solar panel would be a nice addition as well.

Edit: You could hypothetically manually set the switch to Bat 1&2 while the engine is running, then switch to Bat 1 when not running (leaving the accessories connected to Bat 2 only), but an isolator would automate that for you, and eliminate the chance you'll drain down both batteries.

 

[wrcsixeight]

While marine batteries will say deep cycle on them, the plate number and thickness is much closer to a starting battery than to a true deep cycle battery like a 6v GC-2 battery or an L-16.

Even the best marine batteries, like from Trojan, are only rated at half the total number of cycles.

These "lab" cycles assume the battery will be fully charged after each and every 50% discharge.

In reality your Yahama will lnever ever actually fully charge either battery if drained below 95% charged, so unless you plug in to recharge, the best most expensive battery, is not going to last much longer than the worst, as no loead acid battery is immune to chronic undercharging.

You can charge different size and age batteries in parallel, but this is not ideal.
But I would not discharge them in parallel, or leave them hooked in parallel with no loads on them.

On Odyssey or Northstar AGM battery is a great dual purpose/ marine battery, as they have extremely high CCA/MCA/PCA ratings, and can handle deep discharges, but they also require high amp recharges when drained to 50%.

If you have no intentions of plugging in a charger to top the theoretical second battery up, then get the cheapest battery you can find with the best warranty, and a group31 is basically the biggest marine 12v battery, and can be as high as 130AH of capacity. For an Aux battery you want higher capcity, not higher CCA or MCA.

There are only a few 12v true deep cycle flooded batteries though every marine battery will say so on its sticker. They are a GC-15 size group and one of the best available is the Trojan T-1275. It is about an inch and a half taller than a group 31 with similar footprint. No CCA rating, but 150Ah of capcity. I believe that USbattery makes them for interstate, and Eastpenn Deka also make a GC-15 size group. The GC-15 are sometimes also called scrubber batteries, as in floor scrubber.

The best battery chrnoically undercharged will not last as long as the worst battery regularly returned to full charge, so if you are not planning on plugging in to return both batteries to full charge then go for cheap with warranty and expect to use it.

 

[Sierra048]

Originally Posted By: wrcsixeight
While marine batteries will say deep cycle on them, the plate number and thickness is much closer to a starting battery than to a true deep cycle battery like a 6v GC-2 battery or an L-16.

Even the best marine batteries, like from Trojan, are only rated at half the total number of cycles.

These "lab" cycles assume the battery will be fully charged after each and every 50% discharge.

In reality your Yahama will lnever ever actually fully charge either battery if drained below 95% charged, so unless you plug in to recharge, the best most expensive battery, is not going to last much longer than the worst, as no loead acid battery is immune to chronic undercharging.

You can charge different size and age batteries in parallel, but this is not ideal.
But I would not discharge them in parallel, or leave them hooked in parallel with no loads on them.

On Odyssey or Northstar AGM battery is a great dual purpose/ marine battery, as they have extremely high CCA/MCA/PCA ratings, and can handle deep discharges, but they also require high amp recharges when drained to 50%.

If you have no intentions of plugging in a charger to top the theoretical second battery up, then get the cheapest battery you can find with the best warranty, and a group31 is basically the biggest marine 12v battery, and can be as high as 130AH of capacity. For an Aux battery you want higher capcity, not higher CCA or MCA.

There are only a few 12v true deep cycle flooded batteries though every marine battery will say so on its sticker. They are a GC-15 size group and one of the best available is the Trojan T-1275. It is about an inch and a half taller than a group 31 with similar footprint. No CCA rating, but 150Ah of capcity. I believe that USbattery makes them for interstate, and Eastpenn Deka also make a GC-15 size group. The GC-15 are sometimes also called scrubber batteries, as in floor scrubber.

The best battery chrnoically undercharged will not last as long as the worst battery regularly returned to full charge, so if you are not planning on plugging in to return both batteries to full charge then go for cheap with warranty and expect to use it.


Great explanation. I have two battery chargers/maintainers and plan on using them for the boat batteries to keep them fully charged after use.

 

[wrcsixeight]

A maintainer will not fully charge a discharged battery.

Most smart chargers also stop well short of a true full charge, despite the green light.

OTC 4619

Might have to UNplug the smart charger, load battery until voltage falls below 12.6v, and restart smart charger, then remove load, several times before specific gravity maxes out on all cells.

98% recharged is good, but only half as good as 100% recharged.

Never forget, The 'smart' charger's green light is mocking you.

The hydrometer will prove it, but as they say, ignorance is bliss.

 

[alarmguy]

For a second battery and your use, any simple inexpensive battery will work, dont over spend on it.
I wouldnt spend more then the $75 Walmart price and honestly, second battery, any sealed battery will do even at $50.

 

[Mr_Joe]

Whether one or two batteries, I’m a fan of a battery tender of sorts for batteries that sit a while. I don’t keep any plugged in 24/7, just periodically as required.

I have two of the ‘Optimate’ series if tenders, use them with a bunch of batteries.