We've been using 4 of these for the past 3 years. Working in the automotive industry lead me to these. 2 amps for topping off at the shop and 6 amps at the competition.
http://smile.amazon.com/CHARGE-4506-12V-Smart-Charger/dp/B004RTJOH0?ie=UTF8&keywords=4506%20battery%20charg er&qid=1465490955&ref_=sr_1_2&sr=8-2
Yes they have buttons but they work great, are small in size and <$30 each.