I have a variable voltage/wattage battery and I have heard that some say charge it as often as you can this reduces stress, others say that's bad, some say a combination of long and short cycles but I don't know which is best. My battery's manual said get down to 10% but it doesn't measure it accurately (but I love these batteries so I don't want to change but they are expensive so I want to prolong their life span as long as possible even if that does mean charging them very often.) I do have two so charging often isn't an inconvenience for me if that's what I am supposed to do.