Best House Battery at any cost?

[OrangeCrush]

I need to replace the house batteries on my Pearson 26. I know that there have been a lot of threads on this already, but I'm having trouble making sense of all the conflicting information. Hopefully someone here can tell me what my best option is.

I currently have two large Sears Deep Cycle batteries in parallel. I charge them from my 15hp outboard (which is very slow), a solar trickle charger (which I can't even really see them take a charge from but I assume offsets usage somewhat) and a Shumacher Computerized 15A Charger when I have access to shore power (which usually charges them fully within a couple of hours). The batteries have worked well for me but after four seasons they seem to lose their charge much more quickly than they used to and I need to replace them.

I do some pretty extensive cruising around New England on my boat and I often go off the grid for more than a week at a time. I also don't motor all that much when I can avoid it. I use my batteries for stereo, GPS, radar, cabin and navigation lights, and other small appliances like fans and charging cell phones. I DO NOT use them for starting, as my motor is a pull start only. Because of the crucial nature of these applications and the long periods I go without access to shore power, I want to get the best batteries I can get, even if they are more money. Hooking up to shore power is often the only reason for me to pay for a marina, which I would like to avoid doing as much as possible.

I usually run the house power from both batteries at once, but I use a switch to draw from only one at a time when I'm concerned about running them down too low. I also enter serious conservation mode when necessary, cutting down on stereo, cabin lights and other luxuries. Radar, GPS and nav lights just need to work, though. I was able to use the existing batteries for up to 10 days between plugging in, which would result in them showing about 35% when I finally did hook up.

My batteries are strapped down in two plywood compartments in the lazarette, which is ventilated well but also shares air space with the gas tank (which is not very close by and is vented separately to the outside). The batteries also share air space with the cabin and living quarters. It hasn't come up, but having a acid leak sounds like a total nightmare to me and that is also something I would like to avoid.

So, I'm considering the Optima Blue Tops since most people have good things to say about their performance and they don't put out any gases. My main concern is that they do not seem to offer true deep cycle batteries, but rather "Dual Purpose" batteries. I don't need starting power, but rather serious deep cycle performance and durability. Is the Group Size 34 Optima Dual purpose battery going to have issues in this house-only application? Or are they ok in a deep-cycle only setting? How well will these charge from the weaker charging sources (outboard and solar) when I am not on shore power?

How would the Optima Blue tops compare to high quality wet-cell batteries? If this is preferable, what is the best one I can get?

Can anyone tell me exactly what the very best battery I can buy is? I really think it's worth the extra money considering how much time I spend worrying about it, and how much marinas charge by the foot.

Any help is greatly appreciated!

Jack

[rwidman]

I understand Boeing has some surplus batteries they may be willing to sell cheap.

Seriously, nobody can tell you what the very best battery for your boat is although many will try.

My choice is the Sears Die Hard Marine Platinum group 31. It might not be the best choice for someone else, though.

[deckofficer]

Jack,

As you probably know lead acid batteries are rated for a-hr on a 20 hour basis. Any draw greater than 0.05 C and due to Peukert effect, you will have less capacity. Plus LA batteries should not be drawn below 50% DOD (depth of discharge) to give the rated cycle life. LiFePO4 cells are rated in a-hr on a 1 hour basis, so this alone means under heavy loads the same 100 a-hr lithium battery will have close to twice the capacity of a 100 a-hr LA. Plus at the end of the cycle the lithium has 20% remaining in the same test that runs a LA to empty. LA at 50% DOD if cared for will give 500 cycles, whereas a LiFePO4 bank taken further down to 80% DOD will give at least 2000 cycles. LiFePO4 is much cheaper in the long run. I have two 12 volt packs that at 100 a-hr for each would be perfect for your use, weigh 30 lbs apiece and can be fully charged in 20 minutes if using a 200 amp charger. I use a small 10 lb 50 amp charger.

[hellosailor]

Jack, you need to understand what's in the pretty package. Optima batteries are simply spiral-wound AGM batteries. Spiral-wound is supposed to be less expensive and more reliable, but Optima batteries are about 30% more expensive than flat-plate AGM batteries, which may be 30% more expensive than wet lead batteries. And since a round Optima cell is a "round peg" in a "square hole" of a rectangular case, you get about 10% less capacity than you would with a flat-plate AGM battery.

So, Optima? Good, sure. Pretty, sure. Damned expensive alternative to flat-plate AGM batteries from any other source.

If you don't want to do the whole long learning curve and debates...Go to Sam's Club or WalMart, buy the biggest wet lead acid deep cycle batteries that will fit, and save yourself a lot of time and money. Then buy a bigger solar panel someplace, because every battery dies an early death if it is cycled deeply or not fully recharged. If there's no place to mount it, just plug it in and put it on the cockpit floor before you leave the boat. (That's far from ideal but better than nothing.)

[Maine Sail]

You probably don't want the "best" because with your battery management habits you'll kill them too and just be out more money.

The best bang for the buck, and perhaps the most abuse tolerant, would be a pair of 6V golf cart batteries from Sam's or Costco... About $85.00 - $90.00 each for 215Ah - 230Ah..

Batteries like yours, with good care and proper use, can easily go 5-8 years. If you are not going to do anything different, charging and use wise, then buy the most Ah, deepest cycle batteries for the least money you can and just replace them when they die..

[Kettlewell]

The best bang for the buck, and perhaps the most abuse tolerant, would be a pair of 6V golf cart batteries from Sam's or Costco... About $85.00 - $90.00 each for 215Ah - 230Ah.

I agree with this, and buy yourself a solar panel or two, even if they are the rollup kind that you only use when at anchor. My Sam's Club has some 12-volt deep-cycle mobility batteries that are around 125 amp hours each, and close in size to GP 31 batteries, but they are more expensive. You can't beat golf cart batteries for bang for the buck, but you will have to redesign your battery box and wiring.

[Stu Jackson]

Maine Sail is right. From your description I'd bet you're seriously undercharging your batteries on a regular basis. If it was my boat, I'd either go to 6V wet cells as Maine Sail suggests (best bang for the amount of lead) or stay with 12V wet cell deep cycles. BUT, you NEED to increase your charging source. Your outboard won't do much, as you already know, and you're not hooked up to shorepower often, right? So, get a larger solar array to be able to meet your energy budget, and keep your house bank topped off, or at least stay within the 50-85% SOC, your batteries will last longer and so will your wallet. Good luck.

[kbudd]

I second the Sam's golf cart batteries. Best for the $$$$.

[OrangeCrush]

Thanks for the advice, everybody.

Over the summer I'm underway pretty much everyday for six weeks straight, and as you guys pointed out I'm not generating enough power to keep up with my consumption. I have two square solar panels out all the time. I can try to lay out more, but I don't have a ton of extra deck space, especially since by the time I can spread them out it's usually late in the day, and Maine conditions are not ideal for solar charging to begin with. Perhaps I'll need to run the motor a little more regularly for charging purposes.

I guess the lead acid batteries won't be any worse in terms of performance under this kind of battery mistreatment, which is bound to continue to some extent. Any real concerns out there over the gases produced while charging or the risk of spilling acid? Is there any coast guard regulations regarding having the batteries in the same general space as a permanent, properly vented gas tank?

The wet cell deep cycles served me well for four years and I don't mind staying the course on that if it's really the consensus.

[Kettlewell]

Maine isn't great for solar or wind generation. It is the only area where I cruised in my cat that I had trouble staying charged up, and I had both extensive solar and wind. You might want to consider something like a small portable Honda generator.

[Maine Sail]

Originally Posted by Kettlewell

Maine isn't great for solar or wind generation. It is the only area where I cruised in my cat that I had trouble staying charged up, and I had both extensive solar and wind. You might want to consider something like a small portable Honda generator.

Actually Maine is not too bad for solar. Our insolation numbers are not too bad in the summer months from about April through about mid August. September through November the performance drops but there is still solar gain..

Even on the boat with the panel mounted flat I can average 4 - 5 hours per day at the panels full "rated" output... Off season I am about 3.5 - 4.5 hours per day at full output. Wind is a real crap shoot in summer but in the spring & fall it is prime...

With our 140W panel we average about 33 - 43Ah's per day in Maine. Some days go higher and some days go lower but those are our averages..

Proper installation taking shade into account, large enough wire to avoid voltage drop and a good controller and Maine is a decent place for solar. While not the best place a well done install still works quite well.

I fix a lot of poorly done solar installs where performance stinks and most often it is the chosen location of the panels or a wiring issue... The big "S" word, "shade", is the most common performance killer, not necessarily Maine...

[s/v Jedi]

Like already mentioned, concentrate on power generation more than on batteries to store it in. How about a small generator with a matched battery charger? You would earn that back quickly because you won't need the marina shore power anymore.

[David M]

At any cost? A fuel cell with a photocatalytic water splitter to replenish the hydrogen combined with enough solar cells, a compressor, controller and hydrogen tanks to make it work. That would truly put you over the tops with the costs.

[Teknav]

Space requirements will not allow catalytic hydrogen generation installed on most sail boats. The suggestion of having a portable Honda generator, is sound. Even though you'll have to deal with another issue; gasoline storage. Mauritz

[nimblemotors]

A hydrogen fuel cell would best "battery" if cost is no object, this 5kw cell is only $23,000
and weighs only 38lbs.


I don't think the OP really means at ANY cost.

If solar and wind generation are not good, then a big battery bank might be called for, in which case Lithium (As deckofficer showed) would be the Best, as you would need a lot of capacity and lead would weigh a lot more.
Running a generator just seems lame for a sailor, sorry had to say it!
You need to determine just how much power you use and how often you can charge up at a marina. Then can determine battery capacity. Doesn't sound like you use a whole lot, so with a little solar and wind a big enough bank would last.