Review on Tenergy 9V NiMH Rechargeable Batteries, 200mAh Long-Lasting Square Battery for Smoke Alarm/Detector (2 Pack) by Steven Lesperance

Do you know the TENS device? It is a cigarette sized power pack used for electrical stimulation of inflamed or healing muscles or surgical sites. I use mine to promote back healing after spinal surgery. It uses a 9 volt battery like the one in your smoke alarm to generate power. I use rechargeable 9 volt batteries to keep battery costs down. But with conventional batteries, a different price has to be paid. Even freshly charged ones don't last long. They "discharge themselves" and after a short time a supposedly fully charged backup battery only holds a partial charge. A partially discharged battery in a TENS device will fail fairly quickly. These Tenergy low self-discharge batteries lose their charge. very little power when not in use. They even last up to a full year according to the manufacturer. In my own daily use, which can drain the battery completely, a charged Tenergy battery will keep you fresh for days when not in use. I can keep multiple batteries on hand for long periods of time and always have a fresh battery when I need it. Tenergy also makes a simple dual-cell charger that fully charges batteries in less than two hours. When I travel I always have it with me along with another Tenergy 9V low self-discharge battery and together with my TENS unit they are literally always ready.