I'm having a headlight problem on my Honda 125cc bike. My problem is that I don't have a battery on my bike and every time I connect a bulb, it blows up within 5 mins. As of this moment I can't afford a battery. I know the bulb is directly connected but I want to know that there is some way I can fix this issue. My mechanic said he'd try maintaining the current, but he blew up the taillight as well. How can I maintain the current?

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    My real suggestion is to not run the bike until you can afford the battery. Not trying to be snippy, I just believe until you get a battery to buffer the current output, you'll keep burning up bulbs, whether on the front or the back. Sep 5, 2014 at 19:27
  • You could start trying to add a resistor into the circuit, maybe add a capacitor too but you're going to need a multimeter plus a fair bit of mathematics to work out what you need. As @Paulster2 says, simply saving up and fitting a battery would be preferable. Surely you can find one second hand at a local vehicle dismantler / scrap / salvage yard fairly cheaply. Jul 15, 2015 at 9:20
  • Please help me., I've decided to buy a indicator for Honda shine bike online..there are two variants available I believe 12.V & 12.5V ..I'm confused what to buy! Kindly reply ...whether buying indicators online is a good choice.
    – jagan
    Dec 28, 2016 at 16:46

3 Answers 3


The voltage regulators on honda bikes are not well built . When you have a battery attached, it gets charged causing a voltage drop. Without it, high uncontrolled power flows through. There is a simple fix, if only the lights are the problem. You can attach voltage regulators on the line the headlight and tail light are attached. They are easy to install. But first check your voltage . For 6v use 7806 For 12v use 7812 The following circuit is commonly used : circuit

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    The 7812 can handle a maximum current of 1.5A, which is just 18W. I don't know the headlight used for this honda, but I guess it's more than 18W. And even if it's sufficient, you'll need a very very big heat sink, as you have to dissipate several watts. Finally, most 7812 need a minimum input voltage of 19V, which is quite much. If the generator doesn't provide this voltage all the time, the light may not be on all the time. There are some versions out there which need just 14.5V.
    – sweber
    Nov 12, 2015 at 9:59
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    Thanks for pointing out the problem, you can use multiple voltage regulators connected in parallel to provide the sufficient wattage. I personally use 7812 manufactured by st and they work fine with a voltage of 12.7 + . And about the heat , the voltage regulators can be screwed on any metal part of the bike with a dab of thermal compound .
    – Arka Patra
    Nov 12, 2015 at 14:03

I had a 70cc honda scooter that did the same thing. The voltage regulators on some of their bikes were pretty screwy... the lower the battery voltage, the higher the output voltage from the gen. I measured mine one time without a battery at over 20 volts output!

The only solution is to get a battery, or try to find a more appropriate voltage regulator. When I looked I never found any off the shelf that I could just bolt on, and I was going to make one, but then I sold it.

If you get a battery make sure to maintain the voltage with a charger when not riding it for a long time.


Without knowing if the bike is 12v or 6v, assuming you don't want to buy a battery, get an LED bulb, they are less apt to blow.

Also, does the bike have a voltage regulator?

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