Bests & Worsts Reviews from Amazon

In a little over a week since this charger arrived I have used it to fully charge the four (6v) deep cycle house batteries (225 AH each) in our motor home (without removing them), the 12v engine battery for same RV, and a huge old Interstate MT-49 Mega Tron II 12v battery kept in the garage as a back-up for emergency jump starting. This big old battery is also my go-to power source for a Turnigy Accucel 6 micro-processor charger for lithium RC batteries, so my hope is this new multi-stage charger will maximize the old battery's longevity. For the past 10 years or so I have kept it alive just occasionally juicing it up with my ancient single-stage Schumacher 6/12v , 2amp/6amp charger. There is no precision to it, just check the voltage periodically and disconnect when it approaches 13v; not optimum charging but taking care not to overcharge it either. This new multi-stage charger is a technological marvel by comparison, providing the percent of charge throughout the process, adjusting the charge to top off the battery based on input from the battery, and it goes into float mode when the charge of the battery connected reaches 100%. One glitch I encountered when charging the old garage back-up battery was that the charger apparently went into float mode prematurely, initially. When I checked on it at one point the green light was on indicating it had switched to float mode, supposedly at full charge. It became evident this was not the case when I checked the voltage. Do this by unplugging the charger from the AC receptacle, wait around 10 seconds for all the charger lights to extinguish, then plug it in again for a voltage readout. It showed 12.6v, not a full charge for a 12v battery like this, so I hit the battery size button to initiate another recharge. This restart produced a reading of 77% and it went on to eventually indicate the battery was fully charged at 13 volts. Considering the battery's age that's probably all it has left in it and I will continue to use it as described until it's finally flat gone. While reading the manual is very helpful to comprehend the charger, I disagree with the review suggesting it must be memorized. Using this charger is very intuitive once you understand it's controls, by reading the manual, and using the charger accordingly. There are only two buttons to choose from. The left one controls battery size where the two options are either a snow flake or a boat. Take the snow flake to mean a battery for a snowmobile, motorcycle, lawn mower, or any similar small battery. Of course the boat icon represents vehicles with larger batteries. It could have been a truck icon or that of an automobile I suppose, but it doesn't matter. I find the juxtaposition of the little snow flake vs. the big boat permanently internalized now, no memorization needed. The other button is battery type, with the choices being Standard, AGM, & Gel. My charging mentioned above has all been on the standard setting. I don't own any AGM or Gel batteries at this time, but if you do you will know it, and simply select the correct option for your battery. Excuse me for going on so long ... out!