One of the best smart chargers for both automotive and deep cycle batteries:

http://www.amazon.com/Black-Decker-VEC1093DBD-Battery-Charger/dp/B000EJQJ1G

Spendy but worth the upgrade from those 30+ year old automotive only chargers.

Smart charging cycle for deep cycle batt's:

http://www.jackdanmayer.com/images/Electrical/batterychargestages.jpg

Last edited by Bend; 07/07/14.