What type/size of battery to use?

[Wolfeboro_Baja]

OK, I need some advice/help. I thought buying a marine battery for my Baja would be easy but apparently it's not. I know this is a long post but I figured it would be easier for folks to answer if they had all the information to start with.

I have a 25 Outlaw with a single 496 Mag HO with twin batteries and a battery switch under the bench seat. I never paid attention to the type of batteries that came with the boat. Currently, I have an AC/Delco group 24 (I think) marine starting battery (battery 2 on the switch) and an Optima red top (automotive) battery (battery 1 on the switch) installed. Yes, I know the Optima is totally incorrect for the application BUT it's functioned admirably for the past 4-5 yrs with no problems whatsoever (until now). During winter storage, I pull both batteries and hook them up to a Battery Tender intermittently over the winter. So far, that system has worked well for me.

We trailer to the lake and normally, when we launch for the day, we use the opposite battery than we used the last time out. The first time out, we were running off the Optima (battery 1). All was good for the day; the engine started normally and all accessories (including CD player/radio used at anchor) worked normally. My problem began when we trailered to come home. What happened was, we forgot to turn off the battery switch. We came home, parked the trailer in the yard and it sat for 3 weeks. Around the end of the 2nd week (or somewhere during the 3rd week), we noticed the CO detector was beeping inside the cabin which usually means a low battery.

The night before we headed out for our second visit to the lake, I needed to retrieve something from the boat. While I was on board, I checked out the CO detector and that's when I noticed the battery switch was still on, switched to battery 1. Apparently, the CO detector had drained the Optima battery (understandable since it's not a deep cycle battery). I plugged the dead Optima (battery 1) into my Battery Tender overnight but it didn't seem to help any in that short period of time. We went out the next day as planned and used the AC/Delco (battery 2). The engine started fine but my radio would not work. The display lit up as usual but there was no sound. I presumed the dead battery might have messed up the processor in the radio so I did a default reset on the radio and the display was still on but there was still no sound. Later on in the day, I noticed the radio display was now blank even though we were running on the AC/Delco (battery 2) and everything else was fine.

So, here are the questions:

1) Is the dead Optima (battery 1) responsible for the radio not working even though we were running on the Delco (battery 2)?

2) How exactly does the battery switch function? I thought if I was running off battery 2, ALL accessories were also running off battery 2 but the non-functioning radio has me confused.

3) What should I be running for batteries? Two marine starting batteries, two marine deep cycle batteries or one of each? Or should I use two marine dual purpose batteries?

I look forward to hearing your thoughts.

WB

[BroadHopper]

First of all, never charge two different batteries at the same time by switching to 'both' on the switch. The battery switch is just that, to allow you to switch between batteries or draw from both, or turn off both batteries. I have shorten the life of batteries considerably by leaving the switch on both. On most boats turning to the off position does not kill the power to the automatic bilge switch. I remember early low grade boats not having this feature so check it out.
Trying to charge two different batteries on both will kill a good battery. The alternator/generator trying to charge the dead battery will also be charging the fully charged battery resulting in damaging that battery.
A starting battery and a deep cycle battery combination will be good for weekend stays on a cruiser. For day cruisers and overnighters two dual purpose batteries is sufficient. Other boats will be good on a marine starter battery. A marine battery will take the pounding of a boat over any automotive battery.

[jrc]

You will get every possible combination before this thread gets tired. Here is mine:

1) You want each battery to be the same so you can swap batteries each trip. You want to swap each trip, so that you regularly charge each battery

2) You must have a starting battery to spin that big block.

3) You don't sleep on the boat away from shore, you don't have a fridge, so you don't need a deep cycle battery.

I would get to marine starting batteries, and switch them each trip, living with the fact that you don't have as much time at anchor as a deep cycle would.

Or you can add a battery isolator or battery combiner, then you would not have switch batteries each trip. The isolator/combiner would charge both batteries every trip. Then I would get one starting and one deep cycle.

[Wolfeboro_Baja]

Thank you both for your replies!

BH, I never run the boat with the battery switch on BOTH. There's a warning on the switch telling me that doing that will burn out the alternator. That's enough of a warning to keep me from doing that! I checked when I bought the boat and was told by Channel Marine's mechanic that the bilge pump is powered even when the battery switch is off. I've seen evidence of that in my driveway after a heavy rain if I neglected to pull the transom plug when I got home.

JRC, yes, we always switch back and forth on the batteries with each use of the boat so I agree, two marine starting batteries would probably be best given your's and BH's examples of usage. I can live with the shorter battery life at anchor because, theoretically, I'll have the other battery to start with if I actually drain the first one on any given day at anchor.

I think I'll pass on the isolator idea; why complicate things when I don't have to? I'm sure it's a great idea in the right situation, I just don't think I need it in my situation.

Anyone have any thoughts on my radio issue? Is it possible the radio is wired to battery 1 regardless of which battery I'm switched to run on on any given day?

[Barney Bear]

We set the battery selection dial on Number 1 on odd days and on Number 2 on even days.

[jrc]

Usually a boat radio has two connections. One is the main power connection, it comes on when the boat systems are on and its connected to the battery that you are using.

The other connection is the radio memory, it is usually wired directly to one battery skipping the battery switch. This allows you to keep all your stations and clock when the battery switch is off.

So if your radio drained the battery all the way down, you may have lost your memory. I don't know if this can screw up the radio beyond just losing station and time. I know my radio has some weird modes, there's "off" and a really "off". Off has lights on the dials and fully off is dark.

My wife always complains that the radio is on when it is off with the lights on.

So you should have few connections directly to the battery, the radio memory and at least one bilge pump, plus sometimes the Mercathode.

[Dave R]

Originally Posted by jrc

Usually a boat radio has two connections. One is the main power connection, it comes on when the boat systems are on and its connected to the battery that you are using.

The other connection is the radio memory, it is usually wired directly to one battery skipping the battery switch. This allows you to keep all your stations and clock when the battery switch is off.

So if your radio drained the battery all the way down, you may have lost your memory. I don't know if this can screw up the radio beyond just losing station and time. I know my radio has some weird modes, there's "off" and a really "off". Off has lights on the dials and fully off is dark.

My wife always complains that the radio is on when it is off with the lights on.

So you should have few connections directly to the battery, the radio memory and at least one bilge pump, plus sometimes the Mercathode.

Agreed: My Sony marine radio will not function unless it's connected to both the continuous +12V ("radio memory" circuit that bypasses the battery switch just like the bilge pump) AND the switched 12V. I'm very confident your radio will work fine with two good batteries.

I recommend getting 600 CCA marine starting batteries. The reduction gear starter on your big block (and mine) does not really tax a battery all that much, especially since we only start them in warm weather. No need to carry big heavy batteries around, that's just wasting fuel.

[Wolfeboro_Baja]

Originally Posted by Dave R

Agreed: My Sony marine radio will not function unless it's connected to both the continuous +12V ("radio memory" circuit that bypasses the battery switch just like the bilge pump) AND the switched 12V. I'm very confident your radio will work fine with two good batteries.

I recommend getting 600 CCA marine starting batteries. The reduction gear starter on your big block (and mine) does not really tax a battery all that much, especially since we only start them in warm weather. No need to carry big heavy batteries around, that's just wasting fuel.

JRC, yes that's exactly how my radio functions; once the batteries are installed in the spring, I turn on the radio, set the button presets and subwoofer output and it retains those settings all summer, even when the battery switch is turned off. I'm not worried about losing the memory, I just want to be sure it works when I replace the dead Optima.

Dave, that's what I'm hoping for, that the radio will return to normal with 2 good batteries installed. I'm somewhat relieved to read your reply. Right now, I just have to verify the group number and CCA of my existing marine battery (the AC/Delco) before I go spend my money.

Soooo, anyone have suggestions on a good battery brand with a decent price vs. performance ratio? I wouldn't mind another Optima (blue top this time!) but the price gives me sticker shock!!

And thank you for all the good input everyone!

[jrc]

I buy middle of the road flooded batteries, AC/Delco, interstate or Diehards. For a Winni boater like me, never on the anchor overnight, I'd rather have fresh batteries more often.

The Optimas are great batteries. They're AGM batteries and hold more and last longer than flooded. But you pay a lot more for them. You also need to make sure your charger supports AGM, usually there is a small switch.

[BroadHopper]

Got a wholesale club card? Check out your club, Sam's and BJ's carries marine batteries. Unless the battery is on sale, you won't find a cheaper good quality battery.

[4Fun]

Originally Posted by jrc

I buy middle of the road flooded batteries, AC/Delco, interstate or Diehards. For a Winni boater like me, never on the anchor overnight, I'd rather have fresh batteries more often.

The Optimas are great batteries. They're AGM batteries and hold more and last longer than flooded. But you pay a lot more for them. You also need to make sure your charger supports AGM, usually there is a small switch.

One note about the new smart chargers. I could not charge my very dead battery with my battery tender or smart Shumacher charger. I had to charge it with an old school charger until it had enough voltage for the smart charger to work.

Maybe you can bring your optima back to life?

[ishoot308]

W.B.

I would recommend two marine deep cycle AGM batteries. These batteries are made for starting power and deep discharging the best of both worlds. Because they are AGM, the discharge rate when not in use is extremely low compared to other battery types.

For a specific brand, you can't beat this Duracell Marine AGM battery for the price.

http://www.samsclub.com/sams/shop/pr...navAction=push

Compare the specs to any other battery out there and you will see what I mean.

Dan

[Wolfeboro_Baja]

Originally Posted by BroadHopper

Got a wholesale club card? Check out your club, Sam's and BJ's carries marine batteries. Unless the battery is on sale, you won't find a cheaper good quality battery.

Yes, I belong to Sam's Club and I've been meaning to check and see what they have available. Ishoot's got a link to a decent-looking battery I'm going to check out.

Originally Posted by 4Fun

One note about the new smart chargers. I could not charge my very dead battery with my battery tender or smart Shumacher charger. I had to charge it with an old school charger until it had enough voltage for the smart charger to work.

Maybe you can bring your optima back to life?

I found a thread on the web with a post from an Optima tech explaining how to try to revive a dead Optima when the charger won't even see it as being connected. I'm going to give that a shot and maybe I can salvage this battery for future automotive use.

Originally Posted by ishoot308

W.B.

I would recommend two marine deep cycle AGM batteries. These batteries are made for starting power and deep discharging the best of both worlds. Because they are AGM, the discharge rate when not in use is extremely low compared to other battery types.

For a specific brand, you can't beat this Duracell Marine AGM battery for the price.

http://www.samsclub.com/sams/shop/pr...navAction=push

Compare the specs to any other battery out there and you will see what I mean.

Dan

The specs ARE impressive; 200 min. reserve capacity and 1000 CA. It sounds like a dual-purpose battery (even though it's not listed as such on Sam's website) which unfortunately is usually the most expensive of the 3 marine battery types. The price listed for that battery you linked to at Sam's is $166 (and it IS available in Concord!) which is almost $20 less than a new Optima marine starting battery; I'm seeing Optima marine dual-purpose batteries listed at $205 and up! I was leaning towards another Optima (marine this time around!) but I may get this Duracell instead.

Thanks for all the great input everyone! I should be picking up a battery somewhere the beginning of next week so I'll be ready for July 4th! See you on the lake!

[brk-lnt]

Originally Posted by 4Fun

One note about the new smart chargers. I could not charge my very dead battery with my battery tender or smart Shumacher charger. I had to charge it with an old school charger until it had enough voltage for the smart charger to work.

Maybe you can bring your optima back to life?

Good point. I'll point out that Optima makes their own charger which is specially designed for AGM (absorbed glass mat) batteries.

Also, with a severely dead battery you can sometimes bring it back by charging it in parallel with another good battery (of the same type/mode/size).