CONTINUOUSWAVE

I have a 1977 Boston Whaler 13-footer.

I’ve been waiting for reasonably priced lithium battery options.

I’m currently running a single OPTIMA Blue Top AGM battery that I replace every two years regardless of usage. I keep the battery on a battery tender [charger] in the garage.

I would like to purchase a small lithium battery or bank of small lithium batteries that will fit in the bow anchor locker. It will be nice to get the extra room on the deck and I could use the weight in the bow.

Currently running off my single battery are:

—55-lbs thrust motorguide trolling motor
—three Lowrance fishfinders with structure scan.
—a sump pump
—a bait well pump
—navigation lamps
—NMEA 2000network
—underwater LED light.
—ICOM marine VHF radio
—accessory power outlet.
—Yamaha F40 outboard

Would it be possible to find a low profile lithium battery that would fit in my bow locker and accommodate my 12 volt needs?

Or possibly a bank of three or four motorcycle batteries?

Will these hold up well to vibration and pounding of a 13-foot skiff?

Thanks in advance for any suggestions. I’m sure many members here have already upgraded.

—Warren

Generally a lithium-ion battery will have higher energy density by both volume and weight than a lead-acid battery, and lithium-ion batteries may have more tolerance for repeated discharge-recharge cycles. Those characteristics are essentially the main reasons for lithium-ion to be preferred over lead-acid.

The lithium-ion drawbacks are cost and a need to manage re-charging more carefully.

In the proposed application the saving in weight does not seem particularly critical. Perhaps a smaller size battery will allow placement in the bow locker.

The price for that will be a doubling or tripling of the cost of the battery.

I have not been continually surveying the price of 12-Volt lithium-ion batteries suitable in energy storage and delivery of current to start an outboard or run a trolling motor for hours. The last time I looked at prices for high-capacity 12-Volt lithium-ion batteries they were quite expensive, about $600 or more. The last lead-acid AGM battery I bought cost $275, and its specifications exceeded any lithium-ion battery I could find, even at three-times the cost.

There is a thread on lithium-ion battery use in the archives:

LiFePO Batteries for Marine Use
viewtopic.php?f=9&t=646&p=29450#p4298

ASIDE: moving the engine starting battery to the bow from the stern will require replacement of the battery cables with new conductors of much larger size, weight, and cost to run back to the transom to the outboard engine. On the other hand, perhaps you already have monster-cable run to the bow for the trolling motor.

Also interesting for me to read is the two-year service life or replacement schedule for the Optima Blue Top AGM battery. If a lithium-ion battery lasted four years in your application, its doubled cost would not be as hard to bear.