This is a good subject. I'm not an expert on this subject but I have done a bit of research on it. NiCad(nickel/cadmium) batteries do not like to be recharged when partially drained. If you like to keep them topped off, you must allow them to discharge almost fully about every 3rd charge because they tend to develop what is referred to as a memory. If you recharge them at the same level all the time they will develop a memory and as soon as they reach that level they will quickly drop to dead. With that said, they also don't like to be drained to absolute dead because they can reverse polarity and then you have a big problem on your hands. Now, moving along to the newer and better Nickel/Metal/Hydride batteries. They hold a charge longer and don't develop a memory. However, you should not keep them fully charged at all times because they also don't like being topped off everyday. They will last a lot longer than NiCads and when they are ready for a recharge, they will rapidly drop in voltage. Pay attention because that's when you need to recharge them. Next is the latest and greatest. The Lithium battery. There are 3 versions of the Lithium battery and the latest version is the best. Lithium batteries will hold a charge for years without the internal resistance causing them to slowly die. You can charge them any way you want and they don't care. I chrge my Handi-Talkie lithiums whenever I see the indicator showing anything that is less than full. As a side note. Lithiums hold their voltage right up to the last minute and then die all of a sudden. Here's the rub. Lithiums have a lifespan of about 10 years and it doesn't matter how well or how bad you treat them. When their time is up, its up, and they stop taking and hold a charge. Basically, Ni/Cads are the only recharge that need special care and handling. Lead/Acid car batteries need to be kept fully charged at all times. They deliver a really high amount of current but die quickly. They should be charged up whenever they reach anywhere near 50% or they won't live a long life. Deep Cycle Lead/Acid batteries deliver a lot less current but can take a long time to drain to empty and can be drained down to about 33% before needing a recharge. Letting either of the Lead/Acid type batteries reach zero is not a good idea. Am I an expert? Nope. I just got tired of listening to all the wives tales and misinformation so I did a little bit of research.
