Mounting batteries under console - 75 SF

[Cape Codder]

Hi Guys, I mounting two batteries under the console on my 75 SF. My question is what's the best way to secure them to the deck?

The fuel tank hatch runs under the middle of the console but there is about 10" on either side that I could drill into. Interested to hear how others have done this and if there are any gotchas to be aware of.

FWIW the boat is completely original.

Thanks!

[JohnC]

I like these
http://www.amazon.com/Moeller-Marine...6XGV7GG770KH7R

As far as mounting it, I guess you could screw it and glue it. That's probably what I would do rather than pulling the hatch and trying to thru-bolt it. Drill a hole and dig out some core if possible, fill with epoxy then re-drill and screw it to the epoxy plug. I would probably make a few globs of 5200 around the screw holes and maybe another in the middle to insure it stays put.

Maybe someone has a better idea for mounting it.

[shine]

Originally Posted by JohnC

I like these
http://www.amazon.com/Moeller-Marine...6XGV7GG770KH7R

As far as mounting it, I guess you could screw it and glue it. That's probably what I would do rather than pulling the hatch and trying to thru-bolt it. Drill a hole and dig out some core if possible, fill with epoxy then re-drill and screw it to the epoxy plug. I would probably make a few globs of 5200 around the screw holes and maybe another in the middle to insure it stays put.
I
Maybe someone has a better idea for mounting it.

I like those, they hold the battery very securely and they are clean looking.

[Cape Codder]

Originally Posted by JohnC

I like these
http://www.amazon.com/Moeller-Marine...6XGV7GG770KH7R

As far as mounting it, I guess you could screw it and glue it. That's probably what I would do rather than pulling the hatch and trying to thru-bolt it. Drill a hole and dig out some core if possible, fill with epoxy then re-drill and screw it to the epoxy plug. I would probably make a few globs of 5200 around the screw holes and maybe another in the middle to insure it stays put.

Maybe someone has a better idea for mounting it.

Thanks for all the suggestions guys. I think I will go with the moeller trays and epoxy the mounting holes.

They are going on either side of the fuel hatch under the console. Is there a depth i should drill out or should I just drill until I hit the bottom later of glass? And what size drill bit would you use?

Sorry for all the questions. I Have not done this before but i want to learn because the boat is original and need to start bringing it back.

[Bushwacker]

Originally Posted by Cape Codder

. . . Is there a depth i should drill out or should I just drill until I hit the bottom later of glass? And what size drill bit would you use?

I'd recommend mounting it like I did the brackets for my galley seat, which can have some significant loads on it in rough seas when occupied by a large passenger! Use machine screws instead of self tapping/sheet metal screws! (The threads on self tapping screws are much sharper than machine screws and tend to cut fiberglass if there is any relative motion!)

1. Use a large drill bit, like 1/2"-5/8".
2. Drill CAREFULLY until it hits the lower sheet of glass, which is only 1 layer (~1/16") thick! If it's a Potter hull with original deck, it's 1/2" balsa core.
3. Fill hole with thickened epoxy.
4. Redrill hole for a 1/4-20 machine screw, using a 3/16" drill. (0.1875" diameter; minor diameter of a 1/4-20 internal thread is 0.196"). Countersink top of hole to assist in starting tap.
5. Tap hole using a 1/4-20 tap. Or you can just cut a slot in a 1/4-20 screw and use that for a tap, as the epoxy is pretty easy to cut.

[Old'sCool]

Mine are in boxes with the standard web strap and their plastic brackets. Never been a problem and easy to get in-out.

[Basketcase]

I've used those Moeller trays and I do like them. However, I had to make new "top plates" out of 1/2" abs because they broke due to a fairly aggressive wake jump in my bass boat. This was fresh water and the batteries are in the stern. I think for ocean with any sort of banging around (like in the console) that they are a bit anemic and will probably break. I say get them, but make a new top piece because they are really a good tray for the most part.

[Old'sCool]

I prefer boxes. They contain any leakage and offer some protection from terminals being "crossed" and case damage.

[Capt Chuck]

CAREFUL !! The fuel line runs under the deck port side in front of the wire races. I screwed into mine ( like a idiot)installing the same brackets. That line is up tight against the deck. Smelled fuel imediately. Had to replace the whole fuel line which was a real pain in the ass.

[FishStretcher]

I'd drill and tap a slab of G10 and slap that on top of the deck with 4200 to keep the top layer hole free. I hold my T top on that way. No joke.

Edit:

I know a lot of people have a love-hate relationship with 3M 5200 and 4200. But personally I don't think using epoxy alone in a hole as an insert is a good idea. Historically sandwich core construction uses large diameter metal hard points to distribute a load on the panel. Epoxy without a reinforcement that has a good load path to the laminate sounds like a recipe for a failure. Batteries are dense, so the acceleration loads can be high as you don't have a lot of space to spread out the load. Getting to the underside to insert a bobbin style hard point is impractical, but a elastomer bond to a G10 load spreader is easy to achieve with G10 and 4200 or 5200. The load is only topside, but that is where the thick laminate is, and the load is over perhaps 100 square inches, not 4 or so. And you don't compromise the deck laminate, so the sandwich core can stay dry.