Ok, so I'm going to reccomend a product, cause it really works, and I'm very impressed.
I replaced all of my batteries last season, I know this is a discussion all of its own, but I went with 8 golf cart batteries, which I find to have the very best bang for the buck.
Here is what the install looks like. (2 of the batteries are not shown)
View attachment 68918
On my prior golf carts, (which were Trojan), I was adding water several times a season.
As you can see, there is no room to put tops on the battery boxes.
I found that with the out-gassing from the batteries, I would have an odor under the floor area from the battery gas
So, I read up on Water Miser battery caps.
Basically what they (claim) to do is recycle the water that is boiling off, and drip it back down into the battery.
This is a close up photo.

Well, here is what I can tell you.
I haven't had to add a drop of water all season. And, very minimal odor, even when the boat is going through a long bulk charge cycle
So,, I think these are great. They were also very inexpensive. I think this has something to do with the fact they were invented for forklifts & golf carts, and not "boats", which jacks up the price by 1000% typically.
I replaced all of my batteries last season, I know this is a discussion all of its own, but I went with 8 golf cart batteries, which I find to have the very best bang for the buck.
Here is what the install looks like. (2 of the batteries are not shown)
View attachment 68918
On my prior golf carts, (which were Trojan), I was adding water several times a season.
As you can see, there is no room to put tops on the battery boxes.
I found that with the out-gassing from the batteries, I would have an odor under the floor area from the battery gas
So, I read up on Water Miser battery caps.
Basically what they (claim) to do is recycle the water that is boiling off, and drip it back down into the battery.
This is a close up photo.

Well, here is what I can tell you.
I haven't had to add a drop of water all season. And, very minimal odor, even when the boat is going through a long bulk charge cycle
So,, I think these are great. They were also very inexpensive. I think this has something to do with the fact they were invented for forklifts & golf carts, and not "boats", which jacks up the price by 1000% typically.