Installing a voltmeter

A modification that will give you instant feedback on the status of your battery and charging system is a voltmeter. This is especially handy if you are running any accessories, as the EX250 doesn't have a lot of electrical headroom.

There are many different kinds of gauges available, but if you ask anyone who ever drove an old American car, the digital ones are much easier to use. Your local auto parts store may have what you need. You can also look at JC Whitney, or search the internet. This installation uses a Datel voltmeter. Another version is shown close to the bottom of this page.

The first step with the installation of your meter is to find a suitable location. Put everything on your bike that you usually carry, such as a tank bag, and find a good place. Take careful measurements, because you only get one chance to not screw up your fairing. Ensure that you can see the voltmeter with a quick glance. On this Ninja 650R the meter was mounted low and to the left, but on the 250, due to a different tank bag, it was determined that up near the windscreen was better.

The first step is to place masking tape over the fairing and outline the necessary rectangular hole. The masking tape helps keep the fairing paint from splintering when drilled.

Four corner holes are drilled just inside the corners, with a small drill bit of your choice. Then, holes are drilled around the perimeter.

Note that this is only a procedural guide; you may have tools that you find will work better for you.

We take this opportunity to again stress the importance of taking your time and not rushing the drilling. Fairings are expensive expensive expensive!!

The next step in this installation was to attempt to use a heated and sharp razor blade to cut through the holes. Unfortunately, the fairing was flexing too much, and this effort was abandoned. Instead, a new, sharp drill bit was used as a saw. This works well, though slowly.

With the interior gone, it's time to smooth out the edges. Break out the file.

After one round of filing, there's still a ways to go.

The Datel voltmeter is constantly checked against the hole to determine where the hole needs to be enlarged. Then, you keep on filing.

The display has a 2-3mm lip that is wider than the body. This holds it in place from above. On the backside there is a metal rectangular retaining clip that holds the body against the mounting surface. There is also a trim piece held by four screws, but it's doubtful that most people would choose to use it with a sportbike.

The wiring on the unit is quite simple. You run two wires; one to positive and one for ground. Add a 3A or 5A inline fuse. Use a power source that is hot only when the key is on. The aux/accessory wires get power ALL of the time, even when there is no key in the ignition. Don't use them. A good location to tap into is the battery side of the horn button. (If you put it on the other side, it'll only work when you honk your horn.) Another option is to get your power from an electrical distribution block. Whatever you do, running the new wires along OEM wires will usually keep them out of the way.

The connections to the meter should be well protected from the weather by the fairings, but if you're concerned you can coat them with dielectric grease.

The finished product is shown here.

Another choice

This five-function meter from CA Sport Touring is larger than the Datel one. It mounts with Velcro. It not only gives you the voltage, but also the time and temperature. It has a pickup in the case and another on a wire suitable for taping to the windscreen with a couple of strips of electrical tape, or a bit of RTV under the suction cup. The temp gauge is nice to have. If you run heated accessories you can readily tell by the voltage whether the battery is charging (13v or so) or discharging (11.4v) or everything is happy, happy, happy (14.7v).

You can mount it between the gauge cluster and the windscreen using a couple of small L-brackets and double-stick tape - - no drilling or anything permanent. Put tape around the corners so it won't scratch the inside of the windscreen. This offers some rain protection in case the bike gets left out in the rain (this unit does not appear to be waterproof). It hooks up three places: ground & battery (front accessory leads for these two), and a switched power lead, such as a tap into the horn or instrument lighting wiring. The switched lead mainly only activates the LEDs and back lighting. The display is on constantly, as is usual for LCDs.

The nighttime illumination is not that good, but it gives you three LEDs: red, amber, and green to indicate roughly less than 12.3v, between 12.3 and 12.7v, and over 12.7. You typically get all three when moving, two when stopped without the heaters or brake on, and only the red with either load added. You can't read the display well at night, and the LEDs are invisible in the daylight, so both display methods have merit.