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Do you think a foldback-class battery charger, with normal charging of 1.5 A and trickle/floating charge of 0.15 A would be a good slow charge? (I am talking about these very simple circuits using an LM 317 integrated circuit very common in the Data Sheets) I have a 12V 7 Ah sealed battery and I'd like to know which is the best charging rate (normal charge and trickle/floating charge) for this type of battery.
São Paulo, Brazil

Trickle/floating charge is less hard on a battery than normal or fast charge. However, letting a lead acid battery sit discharged is worse than any of the above options, as then it will sulfate and this will shorten it's life. However, if you can afford the extra charging time, why not charge at a slower rate. 7 amp-hr divided by 1.5 amp = 4.6 hr.. In my opinion if you slow this down to 12 to 24 hr. for a full charge then it is less likely to over heat and will prolong the life of the battery. This would make the charging rate about .3 to .6 amp. For a float charge to not damage the battery I would use a charging rate of one to 2 weeks for a full charge or no more than .02 to .04 Amps. Remember this is a sealed battery you can not replenish fluids (water) if you force this out as gas due to too high a rate of charging.

Offered by Mike.