The "little box" to which you're referring is one of two things, both of which are designed to get warm (but not burning hot) when your flashlight is recharging. The first, obviously, is the battery; it will naturally warm as it recharges. The second, and perhaps what you're referring to, is a voltage regulator designed to make sure that the battery is getting proper voltage. That second box is also designed to get warm, but over time, as heat sink compound shifts and/or components inside start to age, that can get much warmer while still properly functioning.
Neither of these components is user-serviceable, though either can be replaced if it is defective. A hot battery indicates the possibility of some internal short-circuiting, though if the lamp continues to work, it could simply the be result of increased internal resistance in the battery due to lead plate sulfation.
The bottom line is that you might as well keep using the light as-is until it stops working. At that point, if it's the battery that's been getting hot, you might want to see whether you can get an affordable replacement battery for your light. Otherwise, sad to say, the unit has reached the end of its useful life. I hate throwing items like this away, but without the availability of affordable replacement parts (replacement batteries sometimes cost more than an entire new light!), that may be the only reasonable way to go.
Answers & Comments
The "little box" to which you're referring is one of two things, both of which are designed to get warm (but not burning hot) when your flashlight is recharging. The first, obviously, is the battery; it will naturally warm as it recharges. The second, and perhaps what you're referring to, is a voltage regulator designed to make sure that the battery is getting proper voltage. That second box is also designed to get warm, but over time, as heat sink compound shifts and/or components inside start to age, that can get much warmer while still properly functioning.
Neither of these components is user-serviceable, though either can be replaced if it is defective. A hot battery indicates the possibility of some internal short-circuiting, though if the lamp continues to work, it could simply the be result of increased internal resistance in the battery due to lead plate sulfation.
The bottom line is that you might as well keep using the light as-is until it stops working. At that point, if it's the battery that's been getting hot, you might want to see whether you can get an affordable replacement battery for your light. Otherwise, sad to say, the unit has reached the end of its useful life. I hate throwing items like this away, but without the availability of affordable replacement parts (replacement batteries sometimes cost more than an entire new light!), that may be the only reasonable way to go.
Good luck!