Electrical modifications (Part 2 of 5)

General best practices:

  • Always try to run any additions directly to the battery. Why?
    • This way you don’t tamper the stock wiring
    • Warranty won’t be void this way
    • This way debugging is easier
    • If something goes wrong, your stock is untouched and will still work
  • Use body ground at the same point where stock electrical are connected. Most modern vehicles have this. Its not a good idea to terminate -ve connections to battery
  • Use a voltmeter (DMM) for trouble shooting. Watch out for polarity in all connections

    Use a volt meter

  • Always find out how much current your modification is going to draw, and use the appropriate wire gauge (thickness) (AWG or SQM)
  • Always use an inline fuse on the +ve line
    • Fuses come in 2 types
      • Blade fuse – widely used in cars & imported bikes. Holders are expensive and high quality. We sell them here
      • Glass fuse – very easily available in India, but the holders are cheap and of low quality


  • Always use overlap joins. If possible use quick connectors, posi tap etc. We sell them here
    • Electrical tapes almost always become loose after few months, and are the major cause of electrical failures
    • Better option is to use spade terminals. These come in male female metal contacts and also rubber sleeves
    • Some expensive Superseal connectors are available. These are truly waterproof and help in quick removal and installation. We sell them here
    • Use modern connectors like super seal, no tap, twist lock, press lock. We sell them here


  • Always consider how to waterproof joins.
    • Silicon gel is a cheap and effective way of waterproofing most things provided they won’t come in contact of heat
    • Heat shrink tube is a cheap and effective way of weather proofing joints. This is used by all OEM’s in electrical wiring
  • Keep new wiring away from hot zones like engine or muffler areas. If unavoidable use heat resistant materials and shrink wrap to prevent abrasive damage

Electrical Power

  • Golden rule: Budget the electrical power before any mods
    • A bikes generator will provide a certain amount of power out of which majority will be used by stock parts like fuel pumps, lights, ECU, BCU etc.
    • Before doing any electrical mod, it’s good to know how much spare power is available – google helps in this. E.g.: Ninja 650 generates 336W peak power. Budgeted spare comes to about 80W. Meaning accessories which will draw not more than 80W peak power can be added, but a safe range will be 50-60W. So additional lights (55W HID or LED) can be added along with 12v charger accessory or extra horns. But care should be taken not to use all of them at once. Small spurts of simultaneous use should be ok, as power will be supplied by the battery but prolonged use will drain the battery quickly.

      Plug in volt meter

  • Using a plug in volt meter can help you keep an eye on power consumption. We sell one here which can be very handy to avoid drained batteries on your tours!


  • Golden rule for high current accessories: Use relays, not switches
    • A simple on off switch will be rated for 2A current. Any more current and the switch WILL get hot, WILL create sparking and may melt and malfunction creating a hazard. For devices using more than 0.5A current, relay circuits are the way to go. In India these are called as cut outs.
    • The relay can be driven from pilot lamp or tail lamp connection via a switch to control the connected load. This ensures trouble free, spark free operations. Automotive relays are expensive and big in size and very old school. Sugar cube relays are cheap and compact. But the correct rating must be chosen. Data sheets will show specifications for such relays. The most important aspects are holding current, max contact current and mechanical hold specified in G. The last one indicates how much long the relay will hold its position while going through the crater like potholes on very bad roads.
    • So ignore the helpful fitter who says switches are fine, and insist on a cut out or automotive relay modules
      Relay harness wiring diagram
  • We sell a high quality Relay Harness here. This can form the base of all your electrical modifications. We also love to recommend how to do electrical mods using this harness kit, so feel free to contact us for advice


  • Most automotive switches or small size switches are used to switch accessories/loads using a relay. They are designed for very small currents in mili-Amperes (mA). DO NOT use them for high current by connecting them directly to the load like lights, horns etc. See point 1 in Relay topic above
  • Use high quality switches which are weather proof. Panel mounted switches come with rubber boots for weather protection, but these are very expensive and need drilling into a panel and expert mounting – an expert level DIY task
  • Avoid push pull switches available in local markets as they are not weather proof. The create small sparks due to their construction and generally rust in few months due to the materials used
  • A better and easier option is to use handle bar mounted switches which are weather proof and offer ease of use. These can be easily swapped using the snap lock connector. They are rust resistant too. We sell them here

12v cigarette ports / receptacles

  • Many automotive accessories use a standard 12v cigarette ports or receptacles
  • On a motorcycle, these ports should be weather proof. The one we sell here is water proof
  • These ports should be properly connected using a relay harness to provide the required current for high power accessories like laptop chargers, air pumps etc
  • Remember to turn high power accessories only when your bike is running. Keep other loads like LED lights etc off if your power budget does not allow it.
Hope you found this topic useful. Do let us know if you have any specific questions by leaving your comments please.