Battery box build recommendations

stevemitchell · Dec 7, 2019

Steve DAntonio said:
It sounds as if you are trying to seal the box, to make it airtight, is that right?

Nope, it does not have to be air tight. Just have sturdy sides and a top. At this point my primary plan is to use marine grade plywood and one of the methods listed above to fiberglass it together to give it strength. The lids will be removable for servicing and such - might even make them hinged, which was also a suggestion earlier in the thread.

Steve DAntonio · Dec 7, 2019

Comodave said:
When I have a battery in a box that allows the battery to slide a bit, I cut a piece of Starboard to size and slide it down next to the side of the battery to shim out the extra space so the battery can’t slide at all. The Starboard won’t be hurt by battery acid. I don’t want any movement of the battery, over time it can loosen the cables.

The ABYC standard for battery installation, including movement, is as follows...(underscore is mine).

10.7 INSTALLATION
NOTE: When installing flooded batteries on a sailing vessel, consideration should be given so that the orientation of the battery minimizes the uncovering of battery plates while heeling.
10.7.1 Battery mounting materials and surfaces shall withstand electrolyte attack.
10.7.2 Provision shall be made to contain incidental leakage and spillage of electrolyte.
NOTE: Consideration should be given to:
1. the type of battery installed (e.g. liquid electrolyte or immobilized electrolyte).
2. the boat in which the battery is installed (e.g. angles of heel for sailboats, and accelerations for powerboats).
10.7.3 Fasteners for the attachment of battery boxes or trays shall be isolated from areas intended to collect spilled electrolyte.
[10.7.4 Batteries, as installed, shall be restrained to not move more than one inch (25mm) in any direction when a pulling force of twice the battery weight is applied through the center of gravity of the battery as follows:
10.7.4.1 vertically for a duration of one minute, and
10.7.4.2 horizontally and parallel to the boat's centerline, for a duration of one minute fore and one minute aft, and
10.7.4.3 horizontally and perpendicular to the boat's centerline for a duration of one minute to starboard and one minute to port.

(In Xiamen, China, at the South Coast Yard)

Comodave · Dec 7, 2019

Steve DAntonio said:
The ABYC standard for battery installation, including movement, is as follows...(underscore is mine).

10.7 INSTALLATION
NOTE: When installing flooded batteries on a sailing vessel, consideration should be given so that the orientation of the battery minimizes the uncovering of battery plates while heeling.
10.7.1 Battery mounting materials and surfaces shall withstand electrolyte attack.
10.7.2 Provision shall be made to contain incidental leakage and spillage of electrolyte.
NOTE: Consideration should be given to:
1. the type of battery installed (e.g. liquid electrolyte or immobilized electrolyte).
2. the boat in which the battery is installed (e.g. angles of heel for sailboats, and accelerations for powerboats).
10.7.3 Fasteners for the attachment of battery boxes or trays shall be isolated from areas intended to collect spilled electrolyte.
[10.7.4 Batteries, as installed, shall be restrained to not move more than one inch (25mm) in any direction when a pulling force of twice the battery weight is applied through the center of gravity of the battery as follows:
10.7.4.1 vertically for a duration of one minute, and
10.7.4.2 horizontally and parallel to the boat's centerline, for a duration of one minute fore and one minute aft, and
10.7.4.3 horizontally and perpendicular to the boat's centerline for a duration of one minute to starboard and one minute to port.

(In Xiamen, China, at the South Coast Yard)

I agree, that is why I shim them to take out any sideways movement. Even though the battery box is secured some boxes have room so that the battery can slide back and forth a bit. The Starboard shim stops that movement.

ben2go · Dec 7, 2019

Steve DAntonio said:
It sounds as if you are trying to seal the box, to make it airtight, is that right?

(In Xiamen, China, at the South Coast yard)

Yes and vent it overboard from the bottom of the battery box. I was taught to do it this way in the 80's. Things may have changed since then. I know batteries have. I've only dealt with flooded lead acid and AGM.

twistedtree · Dec 7, 2019

ben2go said:
Yes and vent it overboard from the bottom of the battery box. I was taught to do it this way in the 80's. Things may have changed since then. I know batteries have. I've only dealt with flooded lead acid and AGM.

For flooded batteries, I think you want the vent at the top, or at least an exit at the top. Air coming in the bottom and out the top would be fine. The key is that hydrogen is lighter than air so will collect at the top of a battery enclosure, and needs to be vented out from there.

Propane is just the opposite. It sinks, so propane lockers are vented at their bottom.

Pete Meisinger · Dec 7, 2019

Right now I just use the cheap plastic battery boxes available everywhere. I want to build my own custom box but I am faced with a problem I can't figure out, help me here..

Having suffered a split battery at one time I am aware of the importance of having an acid proof box. Im pretty good with fiberglass and a decent carpenter so that part is simple. Here is the issue, I want one side or end to be hinged so I can slide the batteries out without having to lift them over the edge of the box. I have the vertical room but lifting batteries up the foot or so needed while laying on my belly or knees is getting hard.

Any suggestions?

pete

exmaggiedrum · Dec 7, 2019

Screws for Starboard

djmarchand said:
Starboard will work fine to make your battery boxes from. As you probably know, Starboard doesn't glue well. There are some glues specially designed for Starboard but I have used 3M 5200 and it works ok.

Reinforce the joints with backing strips and put it together with screws. The glue/5200 is more for sealing.

But plywood with a couple of coats of CPE will last just as long and be lots cheaper.

David

Starboard holds together with screws as well as or better than screws with wood from what I was told by my old shop's resident carpenter. And it is certainly strong. I certainly never had a problem with it. Chemicals and fumes don't bother it. But with LiFePO4 batteries that really isn't the issue. Ventilation holes are the most important thing you can do for your batteries though regardless of type. Starboard would not be my first choice for wet acid batteries though as sealants don't stick to it so any leaks would go out the bottom seams. There may be some new caulking or glues I don't know about though that might work.

Steve DAntonio · Dec 8, 2019

stevemitchell said:
Nope, it does not have to be air tight. Just have sturdy sides and a top. At this point my primary plan is to use marine grade plywood and one of the methods listed above to fiberglass it together to give it strength. The lids will be removable for servicing and such - might even make them hinged, which was also a suggestion earlier in the thread.

OK, good. Battery boxes must be vented at the highest point, i.e. in the lid, to prevent entrapment of hydrogen gas (for LA batteries of any type, including AGM). As long as you have that, a gasket is fine, but unnecessary.

(In Alishan, Taiwan)

Steve DAntonio · Dec 8, 2019

ben2go said:
Yes and vent it overboard from the bottom of the battery box. I was taught to do it this way in the 80's. Things may have changed since then. I know batteries have. I've only dealt with flooded lead acid and AGM.

You can vent directly overboard, however, venting must be from the apex, the highest point in the lid. This is because hydrogen gas is lighter than air and rises, a vent at anything other than the apex will not allow all gas to vent.

(In Alishan, Taiwan)

TDunn · Dec 8, 2019

I just finished building a battery box for eight group 31 batteries. I made it from 1/2" exterior plywood that I nailed together. Once the box was together I put fillets of thickened epoxy on all the inside seams and then epoxied two layers of 1708 biaxial fiberglass to the inside of the box. The fiberglass in epoxy is to make the inside of the box water tight and acid resistant. The box is for the batteries for my home solar/battery backup power system so it didn't need to be made to marine standards.

Battery box build recommendations

stevemitchell

Guru

Steve DAntonio

Guru

Comodave

Moderator Emeritus

ben2go

Guru

twistedtree

Guru

Pete Meisinger

Guru

exmaggiedrum

Veteran Member

Steve DAntonio

Guru

Steve DAntonio

Guru

TDunn

Guru

Similar threads

Latest posts