Get a "peak charger" if that is what you mean by "smart charger." Peak charger automatically shut off when the battery is full. Timer chargers will merrily continue to charge your battery at high rates right past full charge into venting, cooking, bursting, and possible fire! Don't waste your time or your batteries on a timer charger. You can typically get entry level peak chargers for $10 more (around 50 bucks).