"So if even a TINY FRACTION of the bubbles enter the tube your battery will quickly overflow."
Another something to think about I geuss, but I think that's also trival somewhat based on the amount of bubbles NOT entering the tube and the fact the vacum has to be broken to let water out. In other words I may get 1/10 the bubbles into the bottle takeing up 2/10 the space of water, but I lose 10/10 of the water as bubbles leaving the battery. I did not catch most of those, so I think that would even out basically and still work fine.
Now if I were catching half the bubbles leaving the battery and that is twice the volume of water, I still break even on the volume of the bottle, water, bubbles. 16oz of bubbles hitting open air, 16oz of bubbles in the bottle, 2 X's the volume of 16oz water. But at halfs that 32oz total bubbles still only takes 16oz of the bottle space. Still only letting out equal amount of water from the bottle as the battery used.
If I were to catch all the bubbles, then I have a problem, 1/2 the bubbles would fill the bottle and force out the other half of the water, not good. Hard to fit 32oz of bubbles into a 16oz bottle too
So the gas bubbles would over flow.
As for the mixing of the acid and water. I think that would not be very much to worry about now. Though a little might mix, we're not talking about a gallon of water, just a few oz's and it's pretty easy to over fill or under fill a large battery by 1 or 2oz's I think. Plus the acid eventaully goes right back in when the water does, not like we're are throwing it away and always adding fresh which would possibly cause a problem eventually. I actaully gave this a little thought. The smaller the battery maybe the more to worry about it. But for something like those L-16 trojans I dought hanging about 8oz of water over them in a 16oz bottle would have any effect really, even a full 16oz bottle? How much water does each cell hold? I had one that was a little low on all 3 cells and used over a gallon of water to fill it when I first got it. I don't remeber what it took, been awhile, but I'm pretty sure I used one new distilled water and opened a second on just one battery. Probably one that hasn't revived yet, it was from the scrap yard. Those have a pretty large area above the plates just for acid I think, probably holds 32oz or close right there.
When I move the batteries at the remote rock house to another location where they will stay (they are not where I want them now) I will try this. I already started saving soda bottles. I think I have 3 now
I don't drink alot of soda. I did find some flavored bottled water the wife and kid likes, so I can use those soon. It's cheap at about 20cents a bottle too, I wonder if it's distilled. Hmmm, blackberry and strawberry batteries
One thing I am thinking about on this acid migration though is making sure it has no effect on the plastic bottles. I don't think it will, but I will probally just take a few drops from a battery and drop in one to be sure anyway.