Yet another battery question

Since I'm new to the forum, I'll start off with greetings and thanks for the valuable information I've already gleaned from all those who take the time to post and share their knowlege and experience.

Now, to the question... after almost 40 years of sailing, I've recently purchased a Nimble Vagabond. The boat, built in 1991, has been extremely well cared for and came with a new (2011, 50 hr) Suzuki 50hp four-stroke. The one thing I don't like is the battery situation I inherited. The stock battery location is a bit tight - inside the small starboard helm console with a tall, narrow door. The electrical panel is in the helm/aft side of this console and inside is/was a near-new flooded marine dual-purpose battery on a battery pad without a box. This makes me very nervous as there is no way to contain electrolyte spills and the space is just a bit too narrow for a box that would fit the battery. (The opening is only 7" wide and the battery touches the sides going in.) I've been doing a lot of reading on the subject but still have that nagging feeling deep in my gut when trying to choose a battery technology. Although Suzuki recommends against using a "sealed" battery with this motor, the folks at Optima told me that a dual-purpose Blue Top (27M or 31M) would work just fine. The other option is to enlarge the opening in the console (the access door should overlap and hide the trimmed edge) enough to fit in a battery box for the flooded battery. Either battery would meet the requirements for cranking the motor and running the few electrics on board (a small Garmin GPS chart plotter, marine VHF, running and anchor lights, two interior lights, and one small electric fan - this is cruising on a shoe-string!).

With all this said, I would greatly value your thoughts on the options available to me. Running a battery cable to the port console for a second battery for the house would be difficult as there is no bilge. The boat will probably be stored on the trailer (either at the house or near the lake) and used a couple of times a months year-round. One or two nights would be the maximum time spent out with day cruises most of the time and I'm prepared to haul the battery home for charging and maintenance.

Thanks!

Rob

Does your outboard charge the battery with it's alternator?If so,you maybe stuck with a flooded lead acid battery.I would check with Suzuki and see if they recommend the use of an AGM.

With all this said, I would greatly value your thoughts on the options available to me. Running a battery cable to the port console for a second battery for the house would be difficult as there is no bilge. The boat will probably be stored on the trailer (either at the house or near the lake) and used a couple of times a months year-round. One or two nights would be the maximum time spent out with day cruises most of the time and I'm prepared to haul the battery home for charging and maintenance

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Rob
How big are we talking 20' boat and what kind of boating are you doing, open water on Lake Superior, out in the salt water, or on a small lake where you can row to shore or flag down another boat? Do you also have a kicker motor that will get you home?

If you are doing open water boating and you're staying overnight on the boat, then a second battery on a switch is going to be desirable for redundancy sake. If you're day sailing on a lake, out for a few hours and then back to the dock or trailer you can probably get by with one battery. Depends on your situation and the type of boating you're doing.

What's under the battery, open bilge? If the battery is enclosed in a cabinet and has ventilation and drainage, possibly it is fine the way it is.
Larry B.

More info

Sorry... yes - the Vagabond is a 20' flat-bottom trailer-trawler. Planned use is on a moderately sized inland lake (one of two within an hour of the house here in South Carolina). The 2011 Suzuki charges the battery (and is electric start), but there is no kicker or trolling motor. One or two nights out will be our longest stay and we will have VHF and cell phone coverage (as well as insurance that covers on-the-water towing). The displacement and freeboard of the boat pretty much preclude "rowing ashore."

There is no bilge in the boat, so the helm console is enclosed (except for one channel leading aft for the wiring) and the wicker panel access door provides good ventilation. It's potential acid leakage on the fiberglass cabin sole inside the console that would concern me with a flooded battery. As I said, Optima specifies two different AGM batteries for this Suzuki motor - I would imagine they wouldn't want to take on the liability if it were not safe to do so.

Thanks for asking questions - let me know if there is anything else you need to know to discuss the situation.

Rob

Although there have been many views, it looks like there's not much interest in helping a newbie with a small boat. Bigger fish to fry, I guess...

Greetings,
Mr. RobL. I did not wade in initially because I am totally unfamiliar with your model of boat but to partially assuage your disappointment at perceived unwillingness to assist, allow me to comment. Would it be possible to install a free standing battery box somewhere in the cockpit or on deck? This would entail running exposed battery cables but would give you the space and battery containment you are looking for. Do you have a swim platform? I would also be uncomfortable with using an unboxed flooded battery.

I'm familiar with the nimbles having been to the factory over on Gunn Highway many times before it closed. Great boats that were well thought out & have been cruised by many people for many miles. Before you start changing the boat I would try using it for awhile as designed. The Optima batteries are expensive but in my opinion they are the best AGM batteries out there. AGMs accept voltage similar to flooded batteries so that should not be a problem. I would, however, get a Boat US or Seatow towing plan before I hit the water.

Rob, I have been following along, but didn't have enough of an idea of what you are doing to add anything. Pictures would help. Anytime a battery is inaccessible an AGM is a good choice. A good battery box should solve the problem of electrolyte spillage with flooded batteries.

Thanks for responding to my whining

Based on Carl's advice and the information from the Optima technical advisor, I think it's a good idea to use the boat for a while before making major modifications. (I would go take a few snaps and post for those not familiar with the boat, but I'm out of town just now for a memorial service). I am willing to spend the money for a good AGM for the peace of mind it would afford. Thanks again to everyone who responded.

Rob

PS - I have boating insurance that covers on-the-water towing, too.

Rob
Personally I would not be happy with an un-boxed flooded battery and would change it for an AGM. I did that on a previous boat where the space I had available would not allow a battery in a box.
AGM charge voltage is compatible with flooded-cell, they will hold a charge for a longer period while untended, they don't require routine watering, they provide higher current output capability, and they don't leak acid. They don't need to be a box, although they should be blocked, strapped, or otherwise restrained.
I think many would say their primary downside is cost, as you have addressed. If you can, I'd swap the battery for an AGM before doing any cutting.
Boat Electric in Seattle last winter said that some customers were not getting the expected life from AGMs, but that a battery charger-conditioner or even better a multistage charger would improve the life.
A solar charger might take care of the charge maintenance and give you a care-free battery system, and a jump-starter from Sears or similar that you load up on the boat when you go out would give you some redundancy.

I have never heard of damage from a std wet batt spillage to a std GRP layup.

With only modest space for the batts the AGM ability to be discharged deeper may be worth the 2X cost?

Weather the outboard alternator has the ability to take advantage of the rapid AGM recharge ability is doubtful.

An SOC meter will keep you advised.

FF

Hi Rob,

What are the dimensions of the batt compartment? My house batts (Deka group 31 AGM) are 12.94" long, 6.75" wide, and 9.38" high. 105 AH capacity. Far better than an Optima for a house batt, and more than adequate for starting your engine.

Optimas are not recommended for deep cycle house banks. They are ideal for start banks, where their spiral-wound form delivers very high cranking amps for starting, winches, davits and bow thrusters. They re-charge quickly after short, high-amp discharges and are much more tolerant of charging voltages than other AGMs. The characteristics that make them great for rapid, high-discharge applications make them less than optimal for house banks. Go for ganged 6-volt batteries: they can be moved into small spaces easily and contained in seperate, small boxes if necessary

Another option to consider for backup is a small portable generator like a honda. It appears that their getting to be pretty popular with cruisers. Might come in handy for extended stays on the hook & that way you can take a tv, coffee maker, blender, toaster oven, juicer .... Ok, forget that idea.

I'll have to admit that I got a good chuckle out of your response, Carl - my wife is quite the "kitchen master" and would probably like to take all of her toys with her. However, we're talking about a 20' boat, here...

There is an Optima reseller just a few blocks from the house and I picked up a Blue Top 31M this weekend for the same price as a 27M on Amazon - with the advantage of dealing with a local, authorized (read warranty honored) reseller. That will resolve the battery box issue for the primary/cranking battery. I like Aquabelle's idea about a couple of ganged 6V deep-cycle batteries for the house, too. These would more easily fit in the corresponding space on the port side to help keep things balanced (this is a 2,500 lb boat - just a very small fraction of the displacement most of you work with).

Great ideas all - and you have helped me immensely. Thanks!

Rob

I remember a thread back on the T&T forum many years ago about a sailor using 1 Optima for his house & starting bank & it had lasted 7 years. So I bought a blue top & it's been starting my little diesel for over 6 years now. I do, however, use 4 T-105s for my house bank. That being said I think that, considering the minimal draw of your system & how little you intend to use it, the one battery will work just fine for your needs.