This subject has crossed my mind recently, as I'm fitting a (sealed) gel battery because with the CCA I need for a starter the only orientation available is to stand the battery on its end. But I'm also fitting a Kubota mini alternator, which reputably put out 14A (12v).
Presumably the regulator will monitor battery voltage and quickly cut back once the energy used has been replaced. Overcharging should therefore not happen, and I'm not overly concerned about a higher than usual charge rate initially as I take the view that if a battery can withstand 200A being drawn, it should stand 200A going back in - momentarily.
Anyone any views on the Kubota / gel combination?
Addendum - in the marine world alternator regulators are available which substantially increase charge rate (usually four stage) but they often have battery temperature sensors, as that's a limiting factor when fast charging. Secondly, these regulators have different settings depending on the type of battery. Normal lead-acid batteries are top of the list as the electrolyte can be topped up, whilst sealed batteries have the lowest setting (although still well above a normal alternator output). As an example my (non-sealed) boat batteries are 140Ah with a CCA of 900A. When low a standard alternator would start charging these at c. 30A, quickly dropping back to c. 20A. but the Sterling regulator increases the alternator's output to around 60A at 15v.