AS-EE,
I'm not trying to push your buttons. We can always use more help answering questions. Please realize your audience - most the people asking the questions here are layman. I believe that was the whole point of Rodney's post. They would not know to use a low current transformer because you didn't specify it in the first place. Just saying low current still doesn't qualify it adequately - 5 amps - 3 amps - 1 amp? Personally on a 7 Ah gel cell I would limit the current to 700 mA.
Second Rodney said that
2. Constant voltage must be maintained to prevent overcharge and again ruining the battery. That value is somewhat temperature dependent but a relatively safe value is 13.6 volts. The circuit shown does not include either of these safeguard.
AS-EE As I'm sure you know, your reply does not take into account the common variations we see on our line voltage coming into the house. I have no problem with your math. It just depends on your point of view but as you well know the quickest way to ruin a gel cell is to overcharge it. I just prefer an active regulated design that can be left connected indefinitely.
John