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Thread: Someone school me on marine batteries

  1. #1
    Member Yukoner's Avatar
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    Default Someone school me on marine batteries

    I want to replace my battery, and I hear talk that the Optima is the way to go.
    Is this so, or is a battery a battery? My Opti needs 1000MCA/800CCA and 180 AH. Is the amp hours as critical as the cranking Amps? The closest Optima only has about 60 AH.
    Also, I was thinking of wiring in a second with a Perko switch, just for insurance. Anyone else do this?
    Thanks guys.
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    Member Akgramps's Avatar
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    180ah is a very big battery, thats like a golf cart battery, seems overkill to me.

    I like the AGM (absorbed glass mat), The optima and Odyssey are both AGM and there are many others, many AGM type batteries are designed to be both starting and deep cycle batteries. AGM and gel cells can handle cold temps (handy in our climate) better than a typical wet cell, which will discharge (slowly) when left out in cold temps.

    I don't think two are really necessary if you have one good one unless you are running trolling motors or some other high load device with the motor off. I have had excellent life out of the few Odysseys I have owned in boats & motorcycles, currently going on 10 years on a MC battery....!
    “Nothing worth doing is easy”
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    Member cormit's Avatar
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    West Marine advisor on battery selection has lots of info. Almost too many choices.

    http://www.westmarine.com/webapp/wcs...y#.UXvgSOBP5hk

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    Member NewMoon's Avatar
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    The West writeup offers a lot of good info.

    Part of your confusion is that motor manufacturers often give misleading recommendations, such as saying your Opti requires 180 AH. That's simply wrong. What your Opti needs is a certain number of cranking amps - like 800 CCA. Cold Cranking Amps (CCA) is a measure of how fast the battery can pump out current. That's what a starter motor needs - a lot of current supplied really fast, for a very short time. Starting-oriented batteries typically can pump out a lot of CA, but have relatively small AH capacity.

    Amp Hours, or AH is a measurement of how long a battery can supply how much current - typically at a much slower rate. This is appropriate for measuring the capacity of a deep cycle battery, for "house" usage, such as running lights, pumps, etc when no charging system is on. To really know how much deep cycle capacity you need you have to add up the usage of the devices you run with the engine off, but it's typically very little for a boat not anchored and lived on overnight.

    Optima's AGM's are typically good starting batteries, but those I've compared specs on don't have great AH capacity for deep cycle use, for their weight and cost. Deka (or Odyssey / Sears Platinum) AGM's seem much better in this respect. I'm a big fan of AGM's, selected and used appropriately.

    A second battery with a switch can provide backup juice if you happen to run down the other battery - but only if you're careful not to keep the switch on Both. It could also give you the option to have a small and light starting battery (like an Optima 34-size), and a house-type battery with greater AH capacity for when your engine is not running.
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    If your asking about the boat in your avatar you don't need a big battery # 24 starting battery will be fine. The advantage of an Optima battery over a normal one is not worth the extra money for what your doing. If you can pull start your engine with out a battery you may not need a 2nd battery and battery switch.

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    Member cormit's Avatar
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    A second battery with a switch can provide backup juice if you happen to run down the other battery - but only if you're careful not to keep the switch on Both. It could also give you the option to have a small and light starting battery (like an Optima 34-size), and a house-type battery with greater AH capacity for when your engine is not running.
    You're right about the battery selector switch. It's nice to have a back up battery ..... especially if you camp overnight in your boat ..... but must be careful as you say .... not to keep the selector on both.

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    Member Bullelkklr's Avatar
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    I think that you might also want to check into what kind of potential damage you can run into by using your outboard motor to charge up a dead house battery.

    When I pull a big load (pot puller) on my battery(ies), I let the main or the kicker run in order to attempt to prevent drawing down either of my two batteries too much. Hitting your outboard alternator with a heavy charging load demand can potentially ruin your alternator in short order. I think that mine is only rated to 35amps....something to check on at a minimum.

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    20 years of fishing on my bowpicker and all i ever had was 2 deep cycle/starting batteries from Costco, always had plenty of juice to start the volvo diesel and run electronics and lights.

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    If your batteries are used for starting, than Amp Hours are not critical. Cranking Amps is what you need for starting.

    If you can afford it, the Optimas (blue top marine starting) are great batteries. Because they are AGM they do not leak, freeze (thats a big advantage), no checking fluid levels, no corrosion (because they are vented), or breakdown as fast. They still should be maintained (charged every few months or put on a trickle charger) in the offseason like any other battery, but really they are the way to go if you can afford it.

    The Odyssey batteries are very good too, but the price on them is a little absurd.

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    Member Yukoner's Avatar
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    Thanks gents
    The only reason for wanting a second battery is because the Opti doesn't have a pull start option. Seems like pretty cheap insurance (and piece of mind) to have a second battery. just in case.
    Never wrestle with a pig.
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    I just run the Nautilus batteries from Canadian Tire in my boat.
    I run a group 27 starting battery for the OB and a pair of group 27 deep cycles for my 24V elect. trolling motor.
    Having 3 batteries really gives peace of mind when you're 100 miles from civilization.

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    Member Akgramps's Avatar
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    Quote Originally Posted by J2theD View Post

    If you can afford it, the Optimas (blue top marine starting) are great batteries. Because they are AGM they do not leak, freeze (thats a big advantage), no checking fluid levels, no corrosion (because they are vented), or breakdown as fast. They still should be maintained (charged every few months or put on a trickle charger) in the offseason like any other battery, but really they are the way to go if you can afford it.

    The Odyssey batteries are very good too, but the price on them is a little absurd.
    The Odysseys are spendy but so is any good battery, not trying to start anything but the Optimas dont really make much sense, a battery is made up of lead and acid, there is more of both in a similar size rectangle battery. If you compare the weight of a Optima to a Odyssey, the Optima is ~ 6 pounds lighter. Both claim 99.99% pure virgin lead.....so it seems to me the Optima is a marketing gimmick......whats the point of round cells anyway......?
    “Nothing worth doing is easy”
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    Member sisusuomi's Avatar
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    I totally agree on the AGM batteries.
    Quote Originally Posted by J2theD View Post
    If your batteries are used for starting, than Amp Hours are not critical. Cranking Amps is what you need for starting.

    If you can afford it, the Optimas (blue top marine starting) are great batteries. Because they are AGM they do not leak, freeze (thats a big advantage), no checking fluid levels, no corrosion (because they are vented), or breakdown as fast. They still should be maintained (charged every few months or put on a trickle charger) in the offseason like any other battery, but really they are the way to go if you can afford it.

    The Odyssey batteries are very good too, but the price on them is a little absurd.

  14. #14
    Member J2theD's Avatar
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    Quote Originally Posted by Akgramps View Post
    The Odysseys are spendy but so is any good battery, not trying to start anything but the Optimas dont really make much sense, a battery is made up of lead and acid, there is more of both in a similar size rectangle battery. If you compare the weight of a Optima to a Odyssey, the Optima is ~ 6 pounds lighter. Both claim 99.99% pure virgin lead.....so it seems to me the Optima is a marketing gimmick......whats the point of round cells anyway......?

    The odyssey has more cranking power head to head than the optima, I'm not debating that. The odyssey has a price tag about double that of the optima. I used to sell both of them for a living, and it's hard to recommend the odyssey over the optima unless $$ isn't an option.
    The round cell is a spiral technology they call it and its been proven to be more efficient than the standard lead acid battery. I had an Optima rep explain the science to me once, but it went over my head.

    On the note of AGM over lead acid, the optimal come with a much much better warranty. 3 year free replacement for starting batteries last time I sold them.

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    Member Akgramps's Avatar
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    Quote Originally Posted by J2theD View Post
    The odyssey has more cranking power head to head than the optima, I'm not debating that. The odyssey has a price tag about double that of the optima. I used to sell both of them for a living, and it's hard to recommend the odyssey over the optima unless $$ isn't an option.
    The round cell is a spiral technology they call it and its been proven to be more efficient than the standard lead acid battery. I had an Optima rep explain the science to me once, but it went over my head.

    On the note of AGM over lead acid, the optimal come with a much much better warranty. 3 year free replacement for starting batteries last time I sold them.
    I would think you would know the AGM is still a lead-acid battery...?

    A AGM is sealed as opposed to a flooded lead acid battery, plate construction and the separators are different on a AGM (among other things but thats the major differences), typically making them hardier than a flooded lead acid battery. But as always some are better than other it just that it cost more to make a AGM anyway so as rule they are a step up over a flooded battery.

    There are many good AGM batteries, from my price checking the Odysseys are comparable to a Optima. I just dont get the Optima and personally I think its all marketing and a bit gimmicky. Granted the round cell technology has to be more difficult and expensive to make but that in itself does not make the, better, if the rep cant explain the advantages I doubt there are any.......Looking at their website offers no insight as to why they are better.....one just needs to believe.

    If a given battery size takes up a specific amount of space then one that has more lead and acid will presumably have more capacity........and my point earlier was that a battery with flat plate technology will have more capacity than one with round cells, it simply stand to reason, regardless if its a Odyssey or Trojan, MK, Universal, Duralast or Diehard....

    I have never sold a battery in my life, I have certainly replaced a few and I think electrical in general and batteries in particular are the least understood systems on a boat and frequently the cause for plenty of aggravation Inadequate charging systems, undersized batteries or the wrong type, poor grounds, the list goes on and on.
    “Nothing worth doing is easy”
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    Member Sierra Hotel's Avatar
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    I'll add a for AGM batteries - at least for the warranties. I bought mine from Sears, and they've replaced them both twice now, with nary a complaint. This is sin the 2 years since I've had them in. Strong battery, always seems to hold a charge (if'n it's not broke). Right now I'm chasing a ground problem on the boat . . . .

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    Hello, I noticed your conversation involving our batteries and wanted to offer some assistance. OurGroup D31M BlueTop is rated at 1,125 cranking amps and is the same battery our sponsored tournament anglers, like Edwin Evers, use to start their 250 Mercs without issue. I've seen some really high manufacturer requirements on reserve capacity, but never really gotten a straight answer from anyone (and we've asked) as to why. Our D31Ms are rated at 75Ah. Have those of you with such high reserve capacity requirements noticed unusually high parasitic draws on your batteries when your boats aren't in use?

    As MacGyver indicated, there are tradeoffs in battery chemistry and construction, that will allow one battery to have more cranking amps and less reserve capacity than another comparably-sized battery that will have more reserve capacity and less cranking amps. More than a few folks have found the ratings on our batteries to be fairly conservative and pound for pound, they are generally competitive with anything else on the market- some may have more reserve capacity and less cranking amps or vice versa.

    Although J2theD suggested our batteries don't freeze, that is not true. Any battery can freeze if it is not at a full state of charge. Fully-charged, our BlueTops are protected from freezing down to -30F, except for the 34M, which is good all the way down to -50F.

    Akgramps, there are several points to the SpiralCell design of Optima batteries. The design of our batteries results in about 30 internal parts, where traditional flat-plate batteries can have more than 120 internal components. One of our internal components is a continuous cast strap, which joins adjacent cells and eliminates welds, which adds resistance and corrosion points between the cells. A cast strap is unique to Optima, proprietary, more expensive, and more difficult to manufacture, but it is a process that gives superior performance. A larger and/or better-designed, manufactured or connected strap will allow better high-current flow due to lower internal resistance, which can be reflected in the CCA rating. This also allows the Optima design to use taller cells, which results in more active material. SpiralCells are also far more resistant to damage from vibration than flat plate batteries, which for boat owners, is sometimes more likely to happen on the back of trailers than rough seas.

    Our automotive batteries come with three-year free replacement warranties, while our marine batteries come with two-year free replacement warranties. Internally, the batteries are identical to each other- BlueTops are the same as YellowTops, except for the 34M BlueTop, which is the marine version of our Group 34 RedTop starting batteries. All the marine batteries do come with additional threaded top posts for marine applications. None of our warranties are voided if our batteries are found to be deeply-discharged or deemed to have reached the end of their useful life, which are notable exclusions in some other AGM battery warranties. If anyone has any specific questions about our batteries, I'll do my best to answer them.


    Jim McIlvaine
    eCare Manager, OPTIMA Batteries, Inc.
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    Member J2theD's Avatar
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    Quote Originally Posted by Akgramps View Post
    I would think you would know the AGM is still a lead-acid battery...?

    A AGM is sealed as opposed to a flooded lead acid battery, plate construction and the separators are different on a AGM (among other things but thats the major differences), typically making them hardier than a flooded lead acid battery. But as always some are better than other it just that it cost more to make a AGM anyway so as rule they are a step up over a flooded battery.

    There are many good AGM batteries, from my price checking the Odysseys are comparable to a Optima. I just dont get the Optima and personally I think its all marketing and a bit gimmicky. Granted the round cell technology has to be more difficult and expensive to make but that in itself does not make the, better, if the rep cant explain the advantages I doubt there are any.......Looking at their website offers no insight as to why they are better.....one just needs to believe.

    If a given battery size takes up a specific amount of space then one that has more lead and acid will presumably have more capacity........and my point earlier was that a battery with flat plate technology will have more capacity than one with round cells, it simply stand to reason, regardless if its a Odyssey or Trojan, MK, Universal, Duralast or Diehard....

    I have never sold a battery in my life, I have certainly replaced a few and I think electrical in general and batteries in particular are the least understood systems on a boat and frequently the cause for plenty of aggravation Inadequate charging systems, undersized batteries or the wrong type, poor grounds, the list goes on and on.
    My argument was not that they were some sort of different science (regarding lead-acid). Surely you must know that how the battery is constructed on the inside affects its performance. AGM's aren't all the same. The Exide Orbital tried to copy the Optima and was a horrible battery. Both Lead Acid, both AGM, much much different performance.

    Odyssey batteries are generally $100 or more per battery than the Optima locally (not many places sell Odyssey locally). And from my experience, the warranty process is MUCH easier through Optima. Odyssey batteries can be hard to find and aren't always in stock. On the other hand, Optimas can be found a lot more places, and are almost always in stock.

    Look up the 78DT size Odyssey and compare it with an Optima Marine Starting. The Odyssey rating is a little because their claim of 1700 CCA is only delivered for the first couple seconds. If you have to crank a bit, or multiple times in a short period of time, it does not hold at 1700.

    I am impartial to both, and my company made more $$ if we sold an Odyssey. Odyssey probably is a better battery, but as I said before, not for the difference in price.

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    Why does 95% of the comm fleet use 4D and 8D batteries then? When I buy a battery the last thing I want to deal with is the warranty. I just buy new batteries every two years no matter what, and if the old ones are good I use them for lighting out at the cabin kept charged with solar charger.

  20. #20
    Member Yukoner's Avatar
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    Hi Jim
    Thanks very much for joining in.
    My boat has a 150 Opti which requires 1000MCA and 800 CCA, OR 180AH. Sorry if I'm repeating.
    My boat has nothing in the way of accessories just a small bilge pump and running lights. I have an outlet which I use to run a spotlight which draws 3 amps.
    In the end I ordered the 34M Optima, as I have no accessory loads. I'm hoping I made the right choice, as opposed to one of the Optima combo batteries.
    Would the 34M still be ok if I was to add say an LED light bar?
    Thanks again
    Paul
    Never wrestle with a pig.
    you both get dirty;
    the Pig likes it.

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