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Annie in WA · 05-08-2013, 06:16

Hi. We have one construction project left to do before we can start provisioning to head South from the PNW. Can I ask for your help on this one? We decided to tear out our old battery box to provide more room between batteries (1/2 inch) to keep them cool in the tropics. Also, because the box wouldnt contain battery acid. i'm doing some research to replace the battery box to store our four 6 volt wet cell batteries and separate starting battery. One option is building a marine plywood box coated with fiberglass. This most likely will be built in place to maximize space in the locker. Another option may be pre made plastic battery boxes like those carried by West Marine.

Is there an option Im missing? What do folks have on their boats and do you like it? A photo would be great... What are people's experiences with the plastic battery boxes for a bank of batteries? Thanks.

Wrong · 05-08-2013, 06:24

Typically battery boxes are of marine plywood assembled with screws and reinforced with fibreglass cloth at the junctures between individual plywood parts. Attachment to the sole or bulkhead is accomplished the same way.

Personally, I would not use plastic boxes.

SVTatia · 05-08-2013, 06:50

Quote:

Originally Posted by Wrong

Typically battery boxes are of marine plywood assembled with screws and reinforced with fiberglass cloth at the junctures between individual plywood parts. Attachment to the sole or bulkhead is accomplished the same way.

Personally, I would not use plastic boxes.

Wrong is right.

But there is nothing wrong with plastic boxes (other than the prices) if you can secure them properly.
I am building mine out of plywood to an adjoining bulkhead it will be glassed over. You have to be very careful with your measurements - specially height (hydrocaps?). Remember that you will be carrying them in, so the opening must be able to accommodate any of the five batteries you have - in or out. You will need a cover and perhaps some ventilation ports. You will also need room for all the bus bars, fuses, ACRs, etc. - stuff that usually goes near the batteries.
Good luck with the project - and keep us posted.

sy_gilana · 05-08-2013, 07:00

Our box is glass reinforced ply. Its framed up in solid timber. There is a groove all round the rim of the box, with an "O" ring. The lid seals this with 6xOver-center latches. Finally there are two vents, one at the highest and one at the lowest, with hoses that run to swan neck tubes on deck. All electrical cables come into the box through compression glands. Theoretically the boat could flood, but the batteries would stay dry. There are 12x Trojan T105's in there. The only change I would make is to put a small computer fan into the lower hose, (the inlet) forcing air into the box.

djmarchand · 05-08-2013, 07:06

Defender sells strong plastic battery boxes that hold two GC batteries for $80. But if the whole reason you are reconfiguring your battery boxes is to keep the batteries cooler (and that has dubious value IMO) then you don't want a box with a top on it. An open top plywood box covered with fiberglass will stay cooler.

David

jeremiason · 05-08-2013, 07:17

In my humble opinion you are wasting your time and space by trying to add voids between the batteries for cooling....

The best way (and cheapest) to construct a battery box would be out of marine plywood, fiberglass and gel coat for easier cleanups. Don't forget to either use battery straps or bolt the hatch down to keep them from falling out during broaches.

Also when you install the new box, make sure you have no water piping or drains near the boxes, since they won't have a drain...

When my boat was designed the battery boxes were just inboard of the hot water heater and all the galley sink water lines. Twice the hose clamps have slipped on the joints and caused the battery boxes to fill with water. Not a hazard, but a pain in the ass to get the water out.

Sandero · 05-08-2013, 08:46

I would recommend maintenance free batts, AGMs ar Gels... but many like wet. If you build a new box it needs to be ventilated. Make it from marine ply. use GRP sheet from McMaster Carr cut to fit as liner and tab the joints with resin and glass cloth strips. Battery acid is nasty and why I like maintenance free... ruin enough things from the acid. I don't think 1/2" spaces will provide enough air flow to cool them... maybe a tiny computer 12 volt blower or exhaust the air?

Chasing Summer · 07-03-2014, 09:13

I'm at the point of installing the battery system on my boat project. I was going to fabricate a fiberglass box. I've read all the posts and that seems to be the norm. Then, recently I read "Marine Survey 101", link was posted in the forum some where, here it is again: Marine Survey 101, your own marine survey checklist
Scroll about 3/4 the way down and there are 3 entries about batteties. There's a picture of acid leaking onto the floor. Here's quote of one of them:

Oh yeah .... the acid is dripping through the deck on to the hull below and eating through the fiberglass.

I surely don't want that to happen.
But here's the question: Does each battery need it's own plastic box or does some one make multiple battery boxes?

SVTatia · 07-03-2014, 10:12

You can find dual 6v battery boxes in several places.
Such as Blue Sea,

http://assets.bluesea.com/files/reso...tery_Boxes.pdf

Chasing Summer · 07-03-2014, 10:55

I'm using series 29 batteries ... you can get them most anywhere. ... and besides, my power needs are very small.

**a64pilot** · 07-03-2014, 11:22

While I believe battery boxes are a must, just to contain the acid, fiberglass is completely impervious to battery acid. It's glass of course
What kind of resin does battery acid dissolve?

smac999 · 09-03-2014, 12:46

I buy plastic boxes from the local battery store. 2x golf cart, 4x golf cart, 2x L16, or 4x L16.

they are just plain square boxes with no attachments. look like this (random website picture) don't know who they are)

http://www.absak.com/catalog/popup_image.php/pID/989

find own way to secure it.

they have some looseness inside. enough to stick some spacers inside if really wanted.

Cheechako · 09-03-2014, 13:01

You could build a plywood battery box the size you want and line it it with thin fiberglass.

Nicholson58 · 09-03-2014, 13:04

Our original box was eaten away by the acid. Batteries were ruptured due to lack of maintenance of the PO. I rebuilt using plywood, glass and Epoxy. As was noted, plastic boxes will contain the acid but you also need to secure the plastic in the case of very rough weather & pounding.

In the end, I didn't want to deal with water, maintenance, venting so we bought AGM Lifeline batteries.