CONTINUOUSWAVE

I'm contemplating relocating the battery on a 1998 GLS 13 to under the bench seat from just in front of the outboard splash well. This would move the battery out of the way and free up the rear deck. I'd also like to move it further to port to offset the weight of the helmsman and be closer to the fuel tank.

An older thread on Whaler Central asked whether it was a good idea to relocate a battery under the console. The general answer was no because the deck isn't reinforced anywhere other than the original location.

I wanted to ask on this forum:
Have [owners of a 1998 GLS 13] moved the boat's battery to a more convenient location?

[For those that have moved the battery] would they recommend for or against this move?

Any information would be appreciated--RPR

[Deleted dead link from post. Moved to MODIFICATIONS and REPAIRS--jimh]

I have not relocated a battery. We have a 1981 Sport 13 and I have thought about moving the battery as you are considering.

First, I believe I would locate the battery beneath the thwart only if it is an AGM because they require so little care.

Second, I would worry very little about a lack of wood backing as our 13 is not a hot rod and is subjected to little rough use. Expansion bolts used with 3M 5200 adhesive sealant for the hold down strap pad eyes should provide plenty of strength to secure the battery box for our use.

Finally, I would replace the battery cables with very good quality cables and redo any cables attached to the battery terminals with fuses inside the battery box to have the fuses in waterproof holders so they will be serviceable without moving the battery. I would use a 316 stainless steel self locking nut to secure all cable terminals to the battery terminals.

Clearly, if a battery box is also held laterally by wood cleats the battery and battery box selected for the project would need to have enough clearance to allow the box & battery to be removed without removing the cleats. If sufficient clearance beneath the thwart is unavailable the thwart could be raised. Frankly, I wouldn't mind a higher rear thwart for comfort while operating the boat.

I don't have a 1998 GLS 13; I have not moved the battery. But since "any information" will be appreciated, I will comment as follows:

When moving the outboard engine battery there are three concerns: the electrical circuit, the weight bearing on the deck, and the attachment points for any hold down fasteners.

If a engine starting battery is moved to be farther away from the engine, the primary electrical power cables will generally have to be replaced. They cannot be effectively lengthened by splicing on extensions; new cables must be used that are one-piece, no splice, and larger wire. For advice on what wire gauge to use for what lengths, see an article in the SMALL BOAT ELECTRICAL forum at

Recommended Battery Cable Size
http://continuouswave.com/forum/viewtopic.php?f=9&t=2153&p=12498

Topics related to small boat electrical problems are discussed in that forum, SMALL BOAT ELECTRICAL.

The second consideration, how the boat deck will bear the weight of the battery in a new location, can be solved by using an above deck plate under the battery to spread the load over a larger surface area. You might also consider using a battery with better electrical power density than a conventional lead-acid flooded cell battery, such as a lithium-ion battery or other newer designs. Or by using a different case shape, one that is lower profile and has a larger surface area footprint; this will also help spread the weight load. Typically on a 13-foot boat the engine will be appropriately sized, and a smaller engine can likely tolerate a smaller starting battery. You do not need to have a 80-Ampere-hour, 1,000-MCA, 85-lbs cranking battery.

Creating reinforced points of attachment for battery hold down can be done in two ways. If a sub-plate is used under the battery, the battery can be secured to the sub-plate. The attachment points on the sub-plate can be through-bolted to the sub-plate with flush or recessed screw heads on the bottom side. Then the sub-plate screwed onto the deck with multiple fasteners. Or, conventional footman's loops can be attached to deck and those fasteners threaded into reinforced points made by creating an imbedded and strengthened attachment point using epoxy resin and filler introduced via a small hole into an area where foam has been removed under the deck.

Thank you Butch and Jim. Great suggestions. Here's where I am as of today:

- I have enough electrical cable (almost too much) to run it under the bench seat since the seat is only 18" further forward than the original battery location.

- Creating a wood cleat/sub-plate under the battery is a good idea; I am thinking of fabricating a teak base plate from left-over stock (unless someone sells such a thing??), screwing it down every 3-4" or so, to the deck, and then running the battery tie downs into the teak. I think this would work nicely.

If you decide to move and want a smaller battery, I found the Cabela's group 22 to be an ideal battery for smaller Whalers. It's AGM, so no concern on spillage and the specs are plenty for motors 70 and under.



The only concern - there's no group 22 battery box offered, so I had to build a custom tray and this is something you could copy for your application. The group 22 also saves about 12# in weight and is currently $50 off.




You should find that most OEM outboard supplied battery cables are plenty long to move the battery around within reason.

D-