Carver Mariner 350 Battery Changup...

[amanphoto]

Hi,

I'm looking for some advice on changing up the batteries in my 99 Mariner 350. The old battery trays being wood are shot, and the batteries where held in pace with trays. Every time I went to check on stuff in the engine compartment, I kept getting stabbed with the battery tie downs.

My current set up is 3 - group 31 batteries. One for each engine and one for the generator. Moving forward, I'm going to replace one of the batteries with an 8D house battery. That will sit nicely in the forward bilge. The two remaining batteries will fit nicely in front of the generator. No issues with space.

My question is, how to secure these snap top style battery boxes? And, What to put them on? The 8D has a nice box with external screw holes. But, the smaller battery boxes are just a box and a cheep strap. I don't want to use the strap. They tend to adsorb oil, water and get grouse.

For the 2 - smaller battery boxes. I'm thinking, I would like to get a two of Stainless steel bars roughly 5" wide x 20" long (the distance side to side between stringers) and about 3/4" thick. Drill through the plastic boxes and tap into the Stainless Bar to mount the boxes. I would 5200 Caulk the bars to the floor of the bilge. The bars will leave room for bilge water to flow by and be easy to clean under.

My concerns are this. I've now put 4 holes in the battery boxes for battery acid to leak out. I could caulk to the holes, but with what? All the battery weight is on the corners of the stainless steel bars. I could bed the stainless into some epoxy, but fiberglass and metal expand at different rates.

Please enlighten me with some suggestions.
Thank you.

[amanphoto]

This is my rough Idea.

[Viper]

There are boxes that have straps that loop through clips on the floor on both sides of the box to hold it down. Here is an example of the type I'm talking about:
https://www.walmart.ca/en/ip/schumacher-electric-marine-battery-box/6000016951625
You can probably accomplish the same thing with off the shelf hardware.

[bud37]

So here is what I did, the same boat and climbing down there on that model is tricky at best, I hear ya about stepping on the rods sticking up.

The front section where you are putting the 8d, I have a bank of 6volts in a lined box with a vented lid...you can kneel on it.The section in front of the generator I have two batteries, like your idea, in boxes screwed down to the shelf, you can seal the screws with polyurethane if you want, that is what battery cases are made from, then made a platform/cover that covers the batteries and fits between the stringers and sits from the generator tray to the cross stringer at the front , leaving cutouts at the side for the generator switch and thru hull. Now you can stand and kneel easily down there without touching the tops of the batteries.The platform/cover can be easily removed and set aside for working below it.

The shelves/trays are just plywood, nothing fancy, just like what came with the boat. I am not suggesting you do it like this, just something to hopefully help with your idea.