Tips on Battery Box Build

[GonzoF1]

What tips can y'all provide to me for building a battery boxes? I know they will need vents and straps, but will wood work? 1/4" ply for the sides and 1/2" for top and bottom? Do they need to be 100% waterproof? Water does drip down from above in heavy rain. The ER hatch is above one end of the space. (42' Navigator) I was thinking of just a top and bottom with no sides to give them air. Do I need to put a thick coat of epoxy or fiberglass on the tops?

Current boxes are the plastic 8D boxes and they won't fit the new config, so I will need a new design.

Thanks!

 

[Bill Roosa]

I'd go for a fiberglass over wood to make it water proof and acid resistant. Also don't forget to engineer a place for the wires to enter/exit so the lid will fit correctly. I would also recommend that you attach the box to the boat and the batteries to the box (straps) so that the whole assemble does not come adrift should you capsize.
good luck

 

[Maine Sail]

Build your box to your design, fillet the inside corners/seams then drop it at Rhino Liner and they will charge you $25.00 to perhaps $50.00 to Rhino Line it... Do not drill though the bottom once lined..

 

[GonzoF1]

Like I said... MainSail recommended it in another thread... Who am I to go against that

I would advise;

One large contiguously wired house bank of 6V GC2's
One start bank of three G27's or three G31's in parallel. (this will will be 1800 - 2400 CA @ 0F)
ON/OFF Switch for starting
ON/OFF Switch for house
EMERGENCY PARALLEL Switch

Feed all charging to the house bank, including the alternators or an alternator and use one of the ACR relays for the start bank. You can start the gen of HOUSE or START your preference. This is a much more simplistic system that is used by many Trawlers.

 

[Maine Sail]

Your choice of G-27 or 31's here really does not matter much. I would however suggest that a dual purpose battery is a slightly more robust battery that will still provide well in excess of what you need for cranking amps. Most Duracell rebranded batteries are made by Deka East Penn but not all...

 

[GonzoF1]

Like I said... MainSail recommended it in another thread... Who am I to go against that

Oh dang it! I posted this under the wrong thread. MaineSail... Can you move this to the other thread, please?

 

[Tacoma John]

To be on the safe side, I built mine out of 1/2" all 'round. Cloth and epoxy covered it and made a sliding fit top that locks into place without any hardware; so it will retain the batteries with less than 3/4' movement, in any direction, even if upside down.
Make sure you allow for ventilation, especially if you plan to equalize lead acid batteries, as the will gas off a bit when doing so.

 

[Gunni]

With FLA batteries you need to have ventilation for the explosive hydrogen gas (lighter than air) which they generate, and contain the extremely corrosive acidic electrolyte that bubbles and collects on and around the batteries. You want to keep all water away from them, drips, and seawater. I have built very strong battery boxes with thin marine ply, covered with woven glass and epoxy. Like that idea to have them coated with Rhino lining!

 

[GonzoF1]

Should there be any air space built between the batteries?

 

[Tacoma John]

You'll need some space, so you can get them in and out. I made mine for 4 Titan T-105 batteries. Since both the USCG CFR's and other jurisdictions, specify that they should not move more than 1 inch, in any direction, I built the box accordingly. The interconnecting cables will allow for some movement. Since I made the box with just 1/2" between the batteries and the underside of the lid, I didn't use any other clamps.
I've since spent time sailing across the Pacific & back, and took an inshore knockdown once, and haven't noticed any problems, nor spilled acid. So, I figure it's a good set up.

 

[ErikFinn]

Build your box to your design, fillet the inside corners/seams then drop it at Rhino Liner and they will charge you $25.00 to perhaps $50.00 to Rhino Line it... Do not drill though the bottom once lined..

Hi Maine Sail,
is this "Rhino Liner" something that can be found in hardware shops outside of USA? I'm currently in Malaysia.. I looked at their website(s) and there was so many products for so many applications and industries that I couldn't figure out what would be the correct one. Which one you recommend? If I can not get that one here what alternative should I look for? "Industrial acid proof epoxy sealant"? Sorry but I'm totally challenged in this field..

 

[Drumvision]

Another idea:

Make a plug with Foamular (owens corning) pannel stick one to the other. Cut it the exact size you need, round the edges. With EPOXY, mat it with 1 layer of 1.5 oz,m 1 layer of bi-axial, close with another layer of 1.5 oz. let it cure. Remove the plug (foamular), remove amine blush with water and soap, sand, If you use West system epoxy with the 207 hardener and your a little willing, you can gelcoat it or Personnaly, for battery boxes, I would paint it.
you then can add any fastener or strap or whatever you want on it event paint: ''I Love My Wife'' on it knowing that it is gonna be hidden in the bilge!

http://epoxyworks.com/index.php/big-nose-pete/

.

 

[GonzoF1]

I am much better with wood

 

[Drumvision]

It look harder than it is the proof of it is that I can do it, so you defenatly can!
But, wood is good to but two things: more roomy when it comes to close quarter and wood soak everything up!
There is no difference between matting wood and foamular. But that was just an idea!

 

[GonzoF1]

Any opinions on acid absorbent pads in the bottom of the boxes?

http://www.newpig.com/pig/US/pig-acid-encapsulating-neutralizing-mat-pad-mat304

 

[GonzoF1]

There is mention of the need to vent the box. Does it need to be vented to the outside of the boat?

 

[Gunni]

Flooded Lead Acid (FLA) batteries produce hydrogen gas during charging cycles. The more charge, the more hydrogen. Placing those batteries in a contained space will allow the hydrogen gas to collect. The gas is lighter than air, so if you don't place the batteries in a location with ventilation, or in external stowage like a lazarrette you will need to provide ventilation. Absorbed Glass Mat (AGM) batteries do not have this requirement.

 

[GonzoF1]

It is a full size engine room. 15' beam and about 20' long.

 

[Gunni]

Well, there should be plenty of ventilation there. In fact my Beneteau had one of the OEM house batteries in the engine room, and I never blowed up, so there is that. However it was a FLA with no cover and my engine was developing lots of surface corrosion that I attribute to the acid vapor floating about. I know it bleached nearby framing, and etched the gelcoat. When I decided to move my house batteries together, and low centered into the boat the design dictated a change to AGM. I simply will not share my living space with a FLA.

 

[centerline]

A DYI product ery similar to rhino liner can be had at most auto parts stores and body shop supply stores.... but probably more expensive than the rhino liner place would charge for the small project.

When constructing a battery box, i would use nothing less than 1/2" if its encapsulated in polyester or epoxy, and 3/4" if its not.
And dont overlook or under estimate Maine Sails comment about the corners... the corners/joints need to be strong because if the battery box cant support a dynamic load of 300lbs of batteries, then you just as well get the plastic ready made boxes and use the little straps that come with them to tie them down... because after the tumble and jumble that will happen in a knock down, and if you are lucky enough to not have a fire as a result, you may be able to reassemble the plastic boxes and the batteries and tie them down again after replacing the plastic attachment points.
whereas, with the poorly constructed "custom" wood battery box, you will be doing it all over again from scratch.....