I use the little Shumacher Smart motorcycle battery charger. It's completely automatic and "senses" the batterys requirements for charging. It knows if you've hooked it up wrong and then sets the charge at the appropriate level. It doesn't charge fast at all and is simply a "maintainer" but my 9ah is fully charged in about 7-8hrs from almost dead.
It must be doing something right because I've charged that battery hundreds of times and it still has the same capacity and isn't bulged out.
It's tiny too. Just a little bit bigger than the battery itself.