I’m sure it has happened to everyone some time or the other. You charge up all your packs planning to go out and fly your quads, and then it starts raining, or for some other reason you don’t get to. And the thing about LiPos is that the longer you leave them fully charged, the more the chemistry degrades. This can lead to reduced performance, or, in extreme cases the battery getting puffed. This has happened to me several times, and I always wanted a way to discharge my packs. Most of the chargers I have owned have had a discharge mode, but only at 5W, meaning that packs take ridiculously long to reach storage voltage and the charger often gets pretty warm.
Here is the solution I have found: this “3-in-1 Battery Balancer, Discharger & Voltage Indicator” from MyRCMart. I believe that for 12$ + shipping, this is a great deal. At 150W, it can discharge most batteries in a matter of minutes. You can set the voltage at which it stops the discharge (3.80-3.85V per cell for storage). It is very simple to use and even keeps your cells balanced during the discharge. One thing you have to watch for is that the 3 bulbs used to discharge the batteries get really hot, so keep them away from anything that can melt or burn. A stone/ concrete floor is perfect, or you can DIY a wooden stand to hold them. Banggood also sells what appears to be the same thing, but at slightly higher price. I am really happy with my unit, and think it’s a great investment for any hobbyist.