I have a dual battery system. Over this winter, one ran low in a couple of cells and its now junk. I do trickle charge them all winter, and I got 10 years (YES 10 years our of both of them). They are the huge group (forget the number).

Anyway, since one is bad, I'm going to replace both. Been doing some online research and it looks like the blue-top Optimas are a favorite. Exide also makes a nice similar battery. They are dual purpose, starting and extended use.

These are both sealed high tech design with about 800 cca.

What do you think, any experience with these types?
What do you use?

I installed the Optima Blue Tops last season. They are still pretty new, but I haven't had any issues with them. No maintenance at all....I left them in the boat all winter and it started right up this spring.

So far, so good....

Not to get off topic but, when you trickle charge them all winter, does that mean they are always hooked up to the charger on trickle 100% of the time? I trickle charge mine a few times over the winter but didn't keep them hooked up the entire time . Should I have been keeping them hooked up on the juice the whole time?

I didn't even have the batteries hooked up to a trickle charger (although I probably should have). The boat was at a boat yard all winter. I left the batteries in, they shrink wrapped the boat, and when we uncovered it a few weeks ago, the boat started right up.

In the past, I have always removed the batts and stored them in my garage. I would put them on a trickle charge every month or so. But with these new sealed Blue Tops, I didn't do anything.

I replaced both mine last Oct, went with the Sears Diehard Marine PM-2 Group 34, Deep Cycle AGM (I understand they are manufactured by the same company that makes the Odyssey battery). Too new to comment. I also installed one of the ProMariner ProSport chargers and keep them plugged in all the time when in the yard.

My original's were both the Interstate Cranking type and only got 3 years! I tried trickle charging using one of the small solar panels/battery during the off-season.

i put two optima blue top in season before last. so this will be 3rd season. i have no issues what-so-ever... but they are still only 2+ years old.

I also run a duel battery system, charging is controled by an ACR, one battery is just for the engine, the other for house loads.. because my run to the fishing ground is short, I fish at night and my engine is fitted with a 20 AMP alternator, my draw on the batteries often exceeds my input, i switched to AGM batteries when the wet cell batteries died (after 4 years).. AGM, have a higher amp acceptance rate than all other batteries and one of the lowest self discharge rate, they are tottlay sealed and can be mounted in any poistion except upside down...when I switched them out, i dropped from Group 27 to group 24... last season was the first one in memmory that i did not need to charge the house battery mid season.... when i put the charger on them this spring... they accepted next to nothing...that's never happend after a winter off...

I just installed an Interstate group27 deep cycle two years ago.
This is the second such battery. The first didn't swim very well.
I only have the one battery on board.
Do you think I should carry a second for offshore dreaming???

I have west marine brand AGM in size 4D, 4 years so far, the only problem is my fault, one of the batteries went stone dead over the winter two years ago when I forgot to shut the switch off. Never got back to its full charge but still cranks the engine after its warmed up.

I have a blue top optima i used to use in my bass boat for the trolling motor, i now use it for everything i can use it for. Running livewell pumps in my truck/boat, running the trolling motor on the little boat, etc...never had a problem with them, and it is around 5 years old i beleave.

Not to get off topic but, when you trickle charge them all winter, does that mean they are always hooked up to the charger on trickle 100% of the time? I trickle charge mine a few times over the winter but didn't keep them hooked up the entire time . Should I have been keeping them hooked up on the juice the whole time?

I have an onboard charger so I "always" plug in at the slip. In the winter, I usually plug in when it starts getting real cold. My reasoning is with lead acid batteries...NEVER let them discharge, especially for a long period. It worked for me, my buddies can't believe I got 10 years out of both batteries.

So,..what I am getting is pretty much what I read on other sites and some reports. The blue tops are the batt of choice. The jury is still out on the Exides, but they are constructed the same way.
I am looking forward to not having acid weeping around in my compartments, not having to check levels, and having plenty of reserve power. Bait well pump, LED deck lights, anchor light, and radios are all on when I am night drift fishing.

BUZZ.. i went to sears-online and looked at the ones you mention 200 bucks each. I found blue tops for 140. Same 3 year warranty for both. I think I will try these out.

BUZZ.. i went to sears-online and looked at the ones you mention 200 bucks each. I found blue tops for 140. Same 3 year warranty for both. I think I will try these out.

I got them on sale last Fall, no where near $200 each!

There is much to be said about shore power & a charger.
Just replaced my 2 group 31s, they were original to the boat (10 years old)
The boat is plugged in year round, at the slip and at home when I haul out in dec.
Old batteries still held a charge but figured why push my luck.
Marine batteries are classed by group,
Group 24, 27, 29, 31
31 is equivalent to a 8D battery in a tractor trailer .
Most production boats come with group 24

van check a1 battery in quincy tommy is very knowledegable

I have two interstate group 27's one for each engine and a D8 for the house battery. I also have digital isolators to keep them all in check.
Check royal battery in Malden. Or call me the interstate truck comes to the shop weekly.
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Oops I'm wrong .My single boat battery is a group 29 deep cycle not a 27

I just installed an Interstate group27 deep cycle two years ago.
This is the second such battery. The first didn't swim very well.
I only have the one battery on board.
Do you think I should carry a second for offshore dreaming???

I personally would never run without 2 batteries. When I anchor up or when I drift and shut the motor off I switch to battery 2 to run all my electronics. When I get ready to fire up the motor I switch to both so I always have one fresh battery to fall back on. To me it's cheap insurance.

I talked to an other buddy today and he said the AGM batteries need a special charger.
I looked at Charles on board chargers and they have three settings.
Lead acid----AGM---GEL, so there seems to be some truth to that or why would there be those settings.

So now I might need to update my charger if I go with AGMs.
:wall::wall::wall::wall::wall:

And the 140$ quote I got was wrong, they were over 200$.

Back to the drawing board !!!!!!:smash::smash:
I could go with good ole' lead acids and leave the charger I have.
That is the shortest cost.

SIVERADO...I have dealt with A1 years back, I totally forgot about them. I will pick his brain and see what I can get... Thanks.

I personally would never run without 2 batteries. When I anchor up or when I drift and shut the motor off I switch to battery 2 to run all my electronics. When I get ready to fire up the motor I switch to both so I always have one fresh battery to fall back on. To me it's cheap insurance.

Wrong way to do it! When you go to start switch to battery 1 only, if you switch to both the current will flow to the weaker battery until both are equally charged. So if you switch to both and battery number 2 is dead, battery number 1 will start loosing charge as soon as you flip the switch, if you engine doesn't start on the first or second try you could be SOL. Unless you have battery isolaters on both batteries. After you start the engine you can switch to both batteries.

not exactly, Mike. The way he does it is fine. The draw down from a weak battery is slow. When he switches to both, he gets the combined power of both batts. If one is weak, it will still be adding to total. If both are weak, at least he will still be getting the combined efforts. If you then run on both, and one has lost ability to hold charge, both batts will equilibrate to lowest voltage. So switching to both for start is fine. You just don't want to sit on both.

not exactly, Mike. The way he does it is fine. The draw down from a weak battery is slow. When he switches to both, he gets the combined power of both batts. If one is weak, it will still be adding to total. If both are weak, at least he will still be getting the combined efforts. If you then run on both, and one has lost ability to hold charge, both batts will equilibrate to lowest voltage. So switching to both for start is fine. You just don't want to sit on both.

Thanks Zac.

Mike, what Zac stated is what my marina mechanic recommended. So far (last 6 years), it has worked out fine. I have new batteries so it has never been on issue. I change them out every 2 years and use the old ones on my tractor, yard truck and assorted junks here on the farm.

I'm digging setups with a BEP VSR.

One engine battery, one house battery, both set to on, ability to flip a switch and use both to start if need be, otherwise they stay isolated and both get charged whenever the engine is running.

I learned that flipping a battery switch while an engine (alternator) is running is a No No. Has that changed?

Nope still not a good idea.
I guess you can blow the voltage regulator.
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I learned that flipping a battery switch while an engine (alternator) is running is a No No. Has that changed?

If its a field disconnect switch it SHOULD be fine.

I learned that flipping a battery switch while an engine (alternator) is running is a No No. Has that changed?

this depends on the battery switch. if the switch disconnects before making another contact then you could have a problem. this is caused by a voltage spike/drop when there is no battery hooked up. the switch in my boat is designed to make contact with the next position before it breaks the last one therefore always being connected to one of the batteries or both. I still don't move it when running just out of habit.

Most ( no all) of the switches are make before break, the most reliable method is to have a switch for each battery ( wired to a third switch as an emergency combiner/isolator)the charging of each battery is acheived through an ACR or Isolator.. each battery having a single purpose... this cuts out the human error ..and need to switch back and forth... it is my understanding that blue seas ( and other manufacturers) now make a single switch that acomplishes this on it;s own.... I still like having the option of excluding one battery all together in case of an internal short...

I learned that flipping a battery switch while an engine (alternator) is running is a No No. Has that changed?

As always the answer is "it depends" Most battery switches will not disconnect the current battery when you move the switch from one battery to both, but check your switch to be sure.

not exactly, Mike. The way he does it is fine. The draw down from a weak battery is slow. When he switches to both, he gets the combined power of both batts. If one is weak, it will still be adding to total. If both are weak, at least he will still be getting the combined efforts. If you then run on both, and one has lost ability to hold charge, both batts will equilibrate to lowest voltage. So switching to both for start is fine. You just don't want to sit on both.

I know its slow, that's why I said if the engine starts right away he'll be fine. But I'll bet you dollars to doughnut that if the engine doesn't start right away he'll forget all about the battery setting while he trouble shoots the engine and by the time he gets around to trying it again one battery will have substantially depleted the other. You cannot get the "combined power" of both batteries, the best you can get is the max CCA of one battery, if the second one is not at max charge it can only take away. The only way you can get the power of both combined is if they are wired in series but then you would have a 24 volt system.

Most ( no all) of the switches are make before break, the most reliable method is to have a switch for each battery ( wired to a third switch as an emergency combiner/isolator)the charging of each battery is acheived through an ACR or Isolator.. each battery having a single purpose... this cuts out the human error ..and need to switch back and forth... it is my understanding that blue seas ( and other manufacturers) now make a single switch that acomplishes this on it;s own.... I still like having the option of excluding one battery all together in case of an internal short...


716-SQ-100AVSR - Dual Battery Charging Cluster (http://www.bepmarine.com/home-mainmenu-8/product-278/716-sq-100avsr-dual-battery-charging-cluster)

Add a Battery - Blue Sea Systems (http://bluesea.com/category/1/productline/overview/329)

The BEP Marine setup is a bit more refined.
It keeps your batteries separated unless you NEED it (Which you really shouldn't, having a dedicated house and a dedicated starting battery really is the way to go.) along with making sure both stay charged when the engine is running.

I decided the extra $$ for the AGM battery is not worth it.
New ones are less than 1/2 the price of AGMs, and if I went with them and they didn't last I'll be REALLY pssd'. So I will go with what has been working. Hope I get another 10 years out of these.:chased:

I bought a new onboard charger so everything will be new.
Got some wiring to straighten out, clean everything, install new trays and the new charger and I'm good to go.

There's a very good reason why most people think AGM's suck.

If you flatline them, good luck re-charging.
If you charge over 16v for any amount of time (which means ever) you kill them. Even 15.5v for any amount of time is bad.

Most stock alternators/voltage regulators WILL kill AGM's.

ie: to do AGM's right and have them last more than 2 years (which seems to be whats happening, my father just replaced a bank of AGM's that were almost 8 years old now, funny how things work right when set up right) you need to be running a GOOD alternator and a GOOD voltage regular (best? Balmar, but not cheap.).

So basically, unless you want to set it up right, and spend alot of money doing so, go buy wet cells, spend the extra money elsewhere and worry not.