Forgive me a moment while I put on my "Mr. Wizard" hat...
A Voltage Regulator is a sandwich of silicone & germanium and being semi-conductors has the unique property of shunting excess voltage above its design spec, 13.8v to 14.2v in the case of most car/motorcycle designs. So it's wired in to an alternator across the +/- poles, and stops the alternator from putting out more voltage when you rev the engine, by shorting the extra juice through itself. It doesn't care how much amps go down the line, just how many volts are across itself.
Lead + sulfuric acid + lead oxide = Lead Acid Battery: the acid eats the plates and produces 2v. When you daisy chain 6 of these cells together you get a 12v battery. Bigger plates allows more amps to be pulled out at once. Shoot extra electricity back into the battery and the chemistry goes backwards, the acid gives back the lead and lead oxide it ate, redepositing on the plates, like the way chrome electroplating works. This is why an ordinary battery life is shortened if drained dead too many times, the plates are deformed from being eaten/rebuilt over and over again.
Lead Acid batteries like being overcharged, it forms little bubbles of steam in the acid/water mix which stirs the acid and keeps the dissolved lead in the acid ready to go back on the plates and, once fully charged keeps the acid from eating the plates any more. This is also why you had to put distilled water back into your battery, to replace the lost steam. (maintenance free batteries are just thicker walled and sealed, trapping the steam and letting it condense back to water when it cools down later)
Lithium Ion batteries do not like being overcharged, they heat up, create gasses inside and splitting the case. Lithium, being an alkali metal, is very reactive and combusts explosively when exposed to oxygen (see Mythbusters). Lithium ion batteries need a 'smart charger' that turns itself down as it senses how charged the battery is, from aggressive charge to slow charge to trickle charge, automatically, based on how much juice the battery is sucking down.
The charging circuit in your cell phone is 'smart', which is why it seems to charge from 20% to 60% in mere minutes, but the last 99% to 100% seems to take hours.
A little google research shows that lithium ion batteries designed as a drop in replacement for lead-acid batteries include a smart charger inside the battery case so that you can use it on a 14.3v system without blowing the battery up.
sorry, I'll climb down from the podium now.....
2009 Honda Rebel 250