Well I bought a battery back up for my MP 40's from a fellow reefer and decided to plug it in and let it trickle charge. It does work I hooked my back up mp40 to it to make sure. But they don't really give much info on the web page and the directions say even less. Hook up is pretty simple but I am wondering if anyone knows how long it takes this thing to fully charge and how do you know when it's charged?? The light on the trickle charger is a solid red. Does it turn green when it is fully charged? Should it be flashing when it is charging ? Any info would be appreciated. I am planning to order a second one this week so I am holding off to mount it so now it's just time to play with it and learn what I can about these. Tx for looking .