On Tue, 1 Jan 2013 11:52:00 -0500, "Tom" wrote:

I was worried about storing in the basement because of the fumes that come
from them. I figured when charging and their bubbling that adds a lot of
chemical fumes into the home. Is that a concern?

Yes, it's a concern. I've done it the wrong way a few times. The
result was a battery box with severely corroded hardware. That's why
battery boxes are usually plastic or wood. No explosions because the
box is vented to the outside air. Hydrogen is lighter than air and
will rise easily out of a vented box.

Our radio club's battery "pile":
http://www.LearnByDestroying.com/k6bj/K6BJ%20Repeater/slides/Batteries.html

This might give you some ideas:
https://www.google.com/search?tbm=isch&q=battery+box

You might also get some hints from the alternative energy groups that
often store their batteries in the basement.
https://homepower.com
There are various schemes involving filtered battery vent plugs,
manifolds, dryers, and absorbers.

Wooden battery box with vent:
http://www.oynot.com/battery-box.html
I'm not thrilled with this method but it probably works:
http://www.oynot.com/battery-box-venting.html

Also, I missed the part where you were trying to charge two batteries
in parallel. Don't do that, at least not with your simple charger.
However, if you must do it, there are numerous articles on the
internet on charging batteries in parallel.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558