This could be of help when we are checking our beloved bikes before and during riding. 1) QUICK BATTERY TEST: Turn on the motorcycle electrical system. Switch headlights on to high beam; owners of enduro motorcycles should turn on their stoplights to load the battery. Start the motorbike, turn on your signals and then sound the horn for about 5 seconds. If the headlights dim/engine stalls/horn volume decreases, the battery cannot supply enough current to power the ignition system/headlights/horn and it should be charged. If the starter motor cranks slowly/cannot turn the engine over and you hear the starter solenoid click, then the same applies. Owners of motorcycles with kickstarters should start the motorbike and sound the horn as described above. 2) CHARGING THE BATTERY: Idling your motorcycle will not charge the battery. The best way to charge it (if you do not have access to a charger) is to take your motorbike for a long run, keeping the revolutions of the engine in the midrange. Ensure that your headlights are set to low beam or "parking mode" to reduce the load on the battery. However, don't get caught travelling with your lights off! If you do have access to a battery charger or DC variable power supply, use the following quick guidelines to charge your battery at a moderate current delivery rate: a) If the battery voltage is 12V, the charge voltage SHOULD NOT EXCEED 15V. If the battery voltage is 6V, the charge voltage SHOULD NOT EXCEED 7.5V. b) Charging current SHOULD NOT EXCEED 1/10th OF THE BATTERY'S RATED CAPACITY. c) You should be done charging the battery in about 10 hours. To establish the battery's state of charge, use a battery electrolyte hygrometer; a fully charged battery will have an electrolyte specific gravity of about 1.28 (the actual figure varies with temperature). Alternatively, if you do not have access to a hygrometer or if you use a sealed battery, remove the charging current and let the battery sit for about 10min. Check the terminal voltage; if it is between 12V to 13V, your battery is fully charged. 3) Establishing what is wrong with the charging system: there are two general cases that can be considered, overcharging and undercharging or no charging. Before assuming that the charging system is at fault we must first ensure that all electrical connections are sound and the battery cables are properly connected. a) Battery 'dies' after being used in motorcycle despite repeated chargings and upon operation of motorcycle at all speeds. Upon checking the battery sulfation is found on the plates: The charging system is not supplying the battery with sufficient current and the battery is being discharged excessively. b) Battery 'dies' after being used in motorcycle at moderate to high speeds; examination reveals a cracked case, low electrolyte levels or reddish deposits on the battery plates. Cables may also be melted: This implies that the motorcycle charging system is overcharging the battery. In case (a): This could be a fault of the rectifier or the generator. Testing takes two parts: testing the rectifier and testing the charging system AC voltage output. In case (b): This is definitely a problem with the rectifier's voltage control/current control circuit. Testing will involve checking the rectifer's resistance values. In both instances, the manufacturer's manual must be consulted to determine the proper test procedure. However, there is a quick way to check if the charging system is charging the battery and at what engine speed this occurs. NOTE: In the interest of safety: PLEASE CARRY OUT THIS TEST ONLY IF YOU ARE FAMILIAR WITH MOTORBIKE ELECTRICAL SYSTEMS. If you're not familiar with motorcycle electrical systems or lack the proper test equipment, please ask a knowledgeable friend for help. You could also email me and I will see what I can do to help you. EQUIPMENT NEEDED: 1) A good multimeter with a DC volt range of AT LEAST 0-20V and a DC current range of AT LEAST -10A to 10A. 2) A set of electrical jumper cables, with good, thick wiring and solid crocodile clips. 3) A pair of rubber gloves to protect you from shock. THE PROCEDURE: This is a 3-part test. PART 1: First, you have to determine the system draw, or how much current your motorbike consumes with the main systems on (headlight and brake lights, for example). Turn off the ignition. Put the bike in neutral. Remove the negative battery cable; TAKE CARE TO ISOLATE IT. Hook up your DC ammeter in the following manner: attach the negative lead to the battery's negative terminal and the positive lead to a good ground point. Turn on the ignition, BUT DO NOT START THE MOTORCYCLE! The reading shown on the ammeter is the amount of current that your motorcycle is drawing with it's main systems on (headlight on high beam). The charging system must therefore output AT LEAST this amount of current in order to sustain the motorcycle electrical system. If the system draw is too high, this will indicate overloading of the electrical system or an electrical short. Zero system draw indicates a broken circuit, probably a blown fuse or a broken wire. My bike draws quite a bit of current with a 110W headlight installed. PART 2: This second part of the test will determine the break even point of the charging system, or the point (in engine revolutions) at which the charging system starts to supply enough power to charge the battery and support the system draw. FOR OWNERS OF KICKSTART BIKES: Kickstart the motorcycle, leaving the ammeter in place. Let the engine idle and note the reading on the ammeter; slowly increase the engine speed and watch the meter for the point where the current draw changes to negative; this will indicate that the charging system has carried the basic load and is now charging the battery. The RPM at which the charging system starts to charge the battery is the break-even point. FOR OWNERS OF ELECTRIC START BIKES: Do not attempt to start the motorcycle with the ammeter connected; the large amount of current drawn by the starter could easily exceed the safety limts of most ammeters, damaging them beyond repair and causing a fire or shock hazard. Instead, temporarily disconnect the negative lead of the ammeter; touch the negative battery cable to the negative battery terminal. Start the motorcycle, remove the negative battery cable and reconnect the ammeter. Follow the same steps as above to obtain the break even point of the charging system. An unusually high break even point indicates that the charging system might be having trouble coping with the system draw; remember, when you're running the motorcycle, you need to add the power consumed by the CDI system to the system draw, and this could mean that your charging system is inadequate for the job. After ascertaining that all connections are sound and that there is a good grounding of all electrical components, try removing some electrical accessories and note the effect this has on the break even point. It is generally not very good to have a high break even point; this will mean that you might find yourself with a discharged battery in stop-and-go traffic, where engine speeds are typically very low. PART 3: The third part of the test simply involves analysing the charging system output at speed; rev the engine up to about 3000rpm and check the ammeter. There should be a good charging current output. Again, if the output at this speed is too low, the charging system may be faulty or overloaded. Shut off the engine, turn off the ignition and disconnect all cables STARTING WITH THE LEADS CONNECTED TO THE NEGATIVE TERMINAL OF THE BATTERY. Re-install the battery leads, ensuring that the terminals are covered with grease before buttoning up everything. I hope this short primer helps you all; I performed these tests to extablish if I could run a 110W headlight on my Honda Steed. So far, everything seems to be going fine; the only change I noticed was that the break-even point of my charging system was *slightly* higher than normal. I don't really need to worry anyway as the Steed's alternator is rated for a nominal output of 345W. If you happen to find any errors in my method or logic, please let me know so I can learn from my mistakes! If you do intend to carry out the tests described earlier, do so with care. Certain motorcycle manufacturers may choose to wire their charging systems in a different manner so use your discretion when deciding how to make your instrument connections. Yap Hui 94 Yamaha GTS1000
