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Old 04-26-2010, 05:37 PM   #1
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Question OPTIMUM Batteries

Does anyone have experience with the Optimum D31M and D34M Marine Batteries. I especially like the "sealed" no maintenance specification(s) of these batteries but would like to read any experienced reviews of the Optimum product(s) in their boats.
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Old 04-26-2010, 06:59 PM   #2
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There are basically 3 types of batteries: Flooded; Gel; AGM. The Optima Blue-Top line of batteries appear to be AGM. In all honesty, most of the benefits reported by Optima are the case of any AGM battery. (e.g. spill proof, maintenance free, resistant to cold weather, can be deeply discharged/recharged, higher volume of recharge cycles; resistant to vibration).

I looked at the spreadsheet and find it a bit interesting. Their spreadsheet is referenced by engine model, not battery. The only specs on the battery are cold cranking amps, but don't give a total number of amp hours, like you'd see in most other deep cycle marine batteries.

Your signature states you have a 3700 SCR. Are these going to be for starting or for house batteries? What do you have now? What are you looking to achieve? (e.g. more amp hours for the house? higher cranking amps for the starters?)

IMHO, I think Lifeline are the best AGM batteries around:

http://www.lifelinebatteries.com/
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Old 04-26-2010, 08:14 PM   #3
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Shrew, thanks for the "words of wisdom" I really appreciate this board and its members. The replacement batteries will be starting and house batteries (more cranking and more house). What I have now is irrelevant they are being replaced. I recently purchased the boat and I am planning to cruise the Bahammas in the summer. I visited the URL you pointed me to. What is your suggestion for lifeline batteries for my boat?
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Old 04-27-2010, 12:35 AM   #4
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I put the bluetop Optimum batteries (from Costco) in my brother's Champion fish/ski..... I've been very impressed with them. They hold-up to all day trolling motor and accessory use and have never let us down, even on two day trips. They are almost three years old now and when we pulled the boat out of storage this spring, they still had their charge.

I'm pretty sure I am going to need to replace the battery on my Maxum this year... it will be an Optimum. (although I will look into Shrew's suggestion also now)
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Old 04-28-2010, 05:22 PM   #5
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All AGM batteries will hold their charge for very long periods of time. unlike a typical flooded battery which looses charge when stored over time, the AGM's do not loose their charge (negligable charge loss) when not being drawn on. You don't really need to keep an AGM on a battery tender over the winter the way you do traditional flooded batteries. They can also be stored on their side, are spill proof and don't offgas and don't need to be topped off. They recharge faster, the charge can be drawn down very low and fully recharged and this can be done several times. This would kill a typical flooded battery.

In my opinion, Deep Cycle batteries can be easily used for both house and starting. However, I would not really say the same for starting batteries which are really only good for starting. I'm providing links to the Lifeline site only because they're site has a good breakdown in the spreadsheets

http://www.lifelinebatteries.com/marinedeepcycle.php

http://www.lifelinebatteries.com/mar...gbatteries.php

Notice how the Starting batteries only give specs on 'Cold Cranking Amps' which are short periods of high surges of amperage and ideal for turning a starter.

The Deep Cycle includes 'cold cranking' as well as "Minutes of Discharge by amperage". Notice on a deep cycle the amperage draw is typically significantly lower, however it occurs over hours rather than seconds.

Starting Batteries: If you're looking for a starting battery, I base it on the overall size of the motor being turned over by teh starter. The higher the cold cranking the better, theoretically.

House Batteries: This is really dictated by what you run on battery, for how long and how often. I'd add up the total amount of amps for devices that are generally run frequently and for long periods. Consider how long you'll need to draw that amperage, then use this number to dictate the amp hour capacity of the battery/batteries you will need to install.


What I can't answer, and hopefully someone here will chime in, is what the deal is with 6V batteries. I noticed there are some 6V batteries with very high amp hours. You'd need at least two wired in series to make it 12V. I'm not sure how that affects amp hours. It would seem these have very high amp hours, however I suspect the amp hours may get cut in half when wired in series for 12v. I'm just a computer engineer, not an electrical engineer so I defer to any members with more knowledge than me. For that matter, I'll be open to any correction. This is just one guys opinion.

If you do go with AGM batteries, you will need to consider a new battery charger with an AGM option. however, unlike Gel batteries are not as susceptible to voltage fluctuations. GEL's typically require some additional equipment to be able to be charged off of the alternator. AGM is closer to flooded in this respect and can typically handle being charged from an alternator much better than GEL.

Just some thoughts.
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Old 04-28-2010, 06:38 PM   #6
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Good write up Shrew.

From what I've read AGM's really don't require anything special in regards to charging, so long as the voltage does not exceed 14.6 ish - which is easily compatible with the output voltage of the typical alternator. True though - GEL's are far more finicky. Regardless, as long as whatever charger you are using doesn't put out more than 14.6 volts it will be compatible with the AGM.

From everything I've read there just does not seem to be a valid reason to NOT use an AGM/deep cycle as a starting battery. They have pleanty of CCA's for the gas engines in our boats. The only time I would seriously be concerned with CCA's is if I were trying to start an engine in very cold weather, say - 32* or below; temps that the typical pleasure boater isn't even thinking of venturing out in. "CCA's" are way over rated I think. The the same way that "Horse Power" (which is not a real number, but actually derived from Torque and RPM) sells engines I think CCA sells batteries. IMHO, the more meaningful numbers are sustained cranking amps and amp hour capacity. Hell, it wasn't that long ago (well, maybe it was) that a 500 CCA battery was sufficient to turn over a big block Chevy engine in the dead of winter.

I just added an Group 24 AGM to my boat as a house battery (also relocated both batts and added a batt switch - but that job will be the subject of a different thread), but kept the existing lead acid starting battery because it was brand new last summer and I kept it on a trickle charger in my garage all winter. The AGM had no problem whatsoever cranking my 350 MAG MPI to life.

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Old 04-28-2010, 07:38 PM   #7
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Hey Guy's this thread has become very insightful.

After a complete review of the information posted and researching the referedced URL'S, I have taken the decision to purchase batteries designed for the purposes that I am intending to use them for. No argument from me that the AGM design/specification can be used as a start battery or as a House battery, providing that allowance is made for the lower CCA'S compared to a similar size starting battery. To the best of my knowledge It will not damage a deep cycle battery that is used as a starting battery, but for the same size battery this battery cannot supply as much cranking amps as a "starting" battery. Living here on the East coast of Florida (yes, sometimes it does get darn cold) and cruising the Bahams and the "out Islands" experiencing a temperature of 0 degrees F was not a realistic consideration in taking my decision. However, other "skippers" of their craft in colder regions should pay heed to all the information that this thread has surfaced.

I enjoy and respect the information exchange that this board has to offer!
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Old 04-28-2010, 07:42 PM   #8
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BTW- I'm using 2 Group 31 AGM Deep Cycles. One for house and the other as my starting battery and it turns over my 496 big block with no issues whatsoever. I'm strongly considering adding a 2nd Group 31 AGM for the house and wiring them in parallel. Retrospectively, I should have just bought a 4d or 8d for the house instead. oh well.
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