Current Hero Honda Splendor headlight is very dim. So I want to put LED for headlight . Is there any effect on battery by doing this?
There are a few things to consider when changing lighting:
1) Draw on electrical system
The draw should ideally be equal to the existing bulb. If it's greater, then you need to make sure the wiring is of a sufficient gauge to handle the load. Drawing more than the existing wires can handle is dangerous. Best case scenario you'll blow a fuse and your new bulb won't work. Worst case is you will overload the wiring, causing it to heat up and catch fire. If the wiring isn't sufficient, you'll need to run larger wire and use a relay to trigger the circuit. You'll also need to make sure the charging system on your bike is sufficient to provide the extra load.
Any energy not turned into light gets turned into heat. For this reason, the efficiency of the bulb is just as important as the draw. If you use a bulb that runs hotter than the stock bulb, you can run the risk of melting any plastic in the headlight assembly.
3) Legal Requirements
Different types of bulbs are meant for different enclosures. For example, HID bulbs are really designed to be used in projector housings that appropriately focus the beam. If you were to use an HID bulb in a housing meant for halogen bulbs, you can blind oncoming traffic. There are likely laws in your area dictating how much light is too much, how much is too little, and how it needs to be focused. How the bulb change affects other drivers and understanding local laws are your responsibility.