I used their solar cell, trickle and now I've added 800. Since I'm a while I've been using their products and haven't had to buy a new one, I was concerned when when I first connected it I only saw a red light on the charger 800, not yellow because I'm used to seeing 3 lights ( Green means it is fully charged, yellow means it needs to be charged and red means the battery is low). So Deltran explained that they removed the yellow light on the 800, so now it just shows green and red light. I know my battery is dead because I had to use a jumper on the battery and as this is a second car the 800 seemed like a good choice. From what I remember, I was told in a conversation that it would take 80 hours for the red light to come on to green status. So I'm going to count the days to see how quickly he comes back. However, I do not work with a deeply discharged battery, but only with a discharged one. I wanted to express this in a review about the difference in lighting on the model 800, I hope this helps anyone who did/didn't know this information. Any Deltran charger is a good charger for me and will be for you too :)