12V 2A Smart Battery Charger & Maintainer with Desulfation - Universal for Cars, Trucks, Motorcycles, ATVs, Boats & RVs | Perfect for Winter Storage, Seasonal Vehicles & Long-Term Battery Maintenance

I have a Corvette and live in snow country. That means putting the car away for the winter. Fortunately, I have a place to store the car. The down side is it isn't heated. Batteries will freeze if they are allowed to discharge. To prevent that, I need to either drive the Corvette regularly, bring the battery inside, or put it on a charger.I started my career in electronics designing battery charging systems for hand held devices. I found that the "Ideal" charger is complicated: different features are needed to quickly charge a battery versus maintain it over the winter. Until recently, you needed a different charger for quick recovery versus long term storage. While not the end-all product, this charger is a great, full featured device that incorporates more of the ideal charger features.Battery chargers come in many types: Bulk Chargers, trickle chargers, and smart chargers like BatteryMINDer.Bulk chargers are designed to quickly recover from a "dead" battery. They tend to have little sophistication, just pouring out lots of energy quickly. This is fine for bringing up a partially discharged battery and getting the car started quickly. But such brutes may overcharge the battery if left on for extended periods. And, they may not have temperature compensation. The bottom line, they may ruin a battery if left connected for extended periods - like the four months I need to store my car.Trickle chargers try to tackle the storage problem. Prior generations of these chargers just used a low-current charger with a maximum voltage output. These "weak" chargers simply don't have the power to quickly recharge a battery, but are reasonable at keeping one "full" under some conditions. They are cheap and somewhat effective.Neither of these "Dumb" chargers deal with significant details of maintaining a battery's charge. The voltage of a fully charged battery varies with temperature - about 12.5mv per degree. That doesn't sound like much, but over the 100 degree temperature variation that is possible with the car in storage, this is 1.25 volts - a significant voltage difference. If the charger's set point is too low, the battery will discharge; if too high, the battery will get too much energy and will over-heat. Such heat kills batteries by boiling off the water in the battery fluid.Battery manufactures publish the "ideal" charge profiles for their products. Here is a typical charge profile: [ Google "lead acid battery charge profile"] This charging profile has four phases: bulk charge, absorption charge, float charge, and testing.The "Smart Chargers" such as BatteryMINDer, solve these problem with with a micro-controller. They sense the state of charge in the battery, the outside temperature, and adjust charging accordingly. The BatteryMINDer provides all of the charge phases listed above, and adds two more: a Qualification phase and a desulfidization phase.- Qualification / Soft Start Phase - this is to test for a very dead battery - The charger is current limited, in this case to just 1/2 Amp. It uses this phase to check for reversed connection of the battery leads, damaged batteries, etc. For a salvagable battery, this phase slowly brings the battery up to a voltage level where it can be charged more quickly without generating excessive, damaging heat.- Bulk Charge/Fast Charge - Here the unit puts out maximum current. The BatteryMINDer puts out 2A. This is far less than typical Bulk Chargers (up to 25 A), but will recharge a typical car battery in about 12 hours. This slower rate makes this charger a poor choice for the quick-fix where you find that you had left your lights on overnight and are late for work. Massive bulk chargers are a better choice here, but are more stressful on the battery.- Float Charge - This mode is where the magic happens in these smart chargers. The Float Mode provides a temperature compensated trickle charge to the battery. It senses the ambient air temperature - or with a low cost accessory - the temperature at the battery - to adjust the trickle voltage and current to the environment. Unlike simple trickle chargers, this mode pulses current on/off to achieve a complete charge. The tender stays in this mode for about 15-60 minutes, depending upon the brand.- Battery Test - This mode turns off the charge entirely for a few minutes and then looks at the voltage over time. It is natural for the voltage to drop slightly. Excessively rapid drops indicate internal issues with the battery. The BatteryMINDer provides an LED indication for a damaged battery. For a normal battery, the rate of voltage drop is fed back into the Float Charge mode to adjust the on/off time of the current pulse to assure that the battery gets only the charge it needs.The combination of temperature controlled float and battery testing makes this the perfect system for long term storage.I ended up buying a cigarette adapter for the system - about $6 more. This saves me the hassle of popping the hood. I just plug the adapter into the cigarette lighter adapter and plug in the BatteryMINDer. (Note: This only works on cars where the accessory/lighter socket is ON when the car is off. GM cars work this way).I have reviewed the datasheets and found this the "Ideal" charger for me. (I still have a bulk/starter charger for the lights-left-on, gotta-get-to-work situation).I will know next spring how well this worked, but I am confident.