Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Very Cool, Maintenance Free Charger!!

This dual battery charger is great! I installed it on my boat myself with a minimum of tools. It keeps both batteries charged and ready to go all the time, and doesn't ever boil out the battery water (although I recommend checking battery water level every couple of weeks). The lights are a nice indicator of charge activity, so you know when and how much they each are being charged. Usually only when I have just come in and plugged in to shore power I will see the red lights for a very short while before they turn to blue and then to green. If the red or blue lights stayed on a lot I would be checking batteries... I would highly recommend this charger to anyone who has a boat or rv with two (separate) batteries and wants them to be ready at a moments notice...