How often does the battery go dead? I wonder why? There must be many Sunday mechanics who have had such experiences. When you have such a feeling, it is important to check the actual measurement of the charge system output. In general, measuring and checking the battery voltage is well known and practiced by many users. However, what is the status of the AC output of the alternator, the generator on the engine side? What is the condition of the DC voltage and current after passing through the regulator rectifier? Surprisingly few users have ever measured these values. Unless these power output conditions are good, the battery condition will not be stable.
In the past, there was a lot of work practice to measure static battery voltage, battery voltage at idling, and battery voltage at engine speed increase with a general circuit tester. However, nowadays, "clamp testers" are easy to buy, so it is possible to check not only the voltage = volts, but also the current = ampere value.
Clamp testers used to be expensive, now they're affordable
Nowadays, clamp testers are sold by various tester manufacturers and by original tool stores. In the past, clamp testers were quite expensive, but nowadays, more and more products are available at relatively affordable prices. The clamp tester I used this time was purchased a few years ago at a price of 10,000 yen, and it can be switched between AC and DC to measure the voltage as well as current.
Checking the battery voltage in the V (volt) range
The V=Volt range is used when checking the battery voltage. Select the V range with the dial and connect the red lead to the + terminal of the battery. When the black lead is connected to the - terminal, the LCD letters "DC" will appear on the left side of the LCD display, indicating DC 12.90 volts DC when measured at idling. When the engine speed was increased to 6000 rpm, the battery terminal voltage showed 14.11 volts DC.
Checking the power output value in the V (volt) range
The three wires rising from the inside of the engine (stator coil) are the three-phase AC output wires in the case of this model. Let's call the three output wires A/B/C, and measure the output data between A and B, A and C, and B and C. When the engine is idling, they all show around 16.8 volts AC, and when the engine speed is increased to 5000 rpm, they all show around 61.5 volts AC. If we increase the engine speed further, the AC output value will increase even more.
Check "DC-A" with a clamp tester
Check the "+-" clearly marked on the clamp part of the clamp tester, and select the dial to the 40A range. Since the battery size is 14AH (ampere-hours), this range should be sufficient. Clamp the lead wire that is tightened to the + terminal of the battery, with the + side of the clamp side display facing the battery side. If you clamp it upside down, the data displayed will be "-/minus". When idling, the display showed around 2.05 amps DC-A, and when the engine speed was increased to 5000 rpm, it showed around 8.04. If the engine speed is increased further, the displayed current = DC-A will increase further. The data measured at the battery terminals is affected by the battery condition. Specifically, if the battery is weak, the voltage and current will increase in an attempt to charge the battery, but on the other hand, if the battery is fully charged, there is no need to increase the voltage and current, so the readings will be suppressed. Of course, this is assuming that the regulator rectifier is working properly.
- Point 1: Let's use the high-performance clamp tester which is now available at a reasonable price.
- Point 2: Let's measure not only the battery voltage but also the AC output when the engine is performing. If it's three-phase AC, it's correct to get the same output data for three systems.
- Point 3: Measure the DC-A amperage at idling by putting a clamp tester between the positive red lead. Let's also measure the DC-A amperage when the engine speed rises.
In the mid-1980s, the moped class shifted from the 6V era to the 12V era. In the mid-1980s, mopeds shifted from the 6V era to the 12V era, and the moped class quickly became more and more electric. In this article, we will check the power generation functions of a Suzuki GS1000 from the late 1970s, which was introduced at a time when the electrical systems of large models were almost completely established.
Before we begin the work practice, let's briefly review the history of the power generation system. Nowadays, the current voltage generated in large quantities is rectified (AC to DC) by a "regulator-rectifier" and the voltage is controlled, but even among the 12-volt models, some models before the early 70's did not have a regulator function (voltage control function), just like the 6-volt models. In the case of single-phase AC power generation, the electricity that passes through the rectifier (rectifier = selenium rectifier was used before the 60's, and later diodes were used) is rectified from AC to DC, and then the voltage is adjusted by the regulator (voltage control device). In the case of 12-volt specification, the voltage is controlled at around 12.8 to 14.5 volts. The controlled voltage changes depending on the engine speed range, and the design ensures that the battery is charged without excess or deficiency (in the case of the 6-volt model, the voltage is controlled at around 6.4 to 7.2 volts).
As mentioned above, many of the older moped class motorcycles were not equipped with regulators, so when the battery condition dropped, the electricity that was supposed to be recharging the battery would flow to the harness side of the motorcycle, causing problems such as the headlight bulb suddenly becoming bright and then suddenly going out while driving at night, and similarly the tail lamp and In the same way, the taillights and indicator bulbs also went out one after another. If the battery condition had been good, the electricity generated would have been kept in balance with the charge consumption. The electrical circuit design should have been such. However, there is a trouble that the light bulb breaks frequently. Many of these problems were caused by the low battery condition, i.e., "insufficient battery liquid". Battery condition was especially important in this era of motorcycles because if the battery fluid was insufficient, it would boil during charging and the fluid would easily dry up.
It's hard to imagine on a modern motorcycle with better electrical management, but there was a time when you had to check the battery level before or after every ride, and that was routine for riders before the 70s.
Three-phase alternating current (AC) power generation is a system that uses a set of three large-capacity generating coils to generate AC power, with the three coils having different generating phases. The three coils are phase-shifted for stable power generation while the engine is performing, and then rectified and voltage controlled through the regulator rectifier. This system then charges the large battery. Here, the battery terminal voltage is measured to determine the condition of the battery, and the "AC voltage" rising from the AC generator during engine operation and the "DC current" after passing through the regulator are checked to see if they are outputting properly. I would like to check the performance of the generator itself. The measurement of voltage (volts) for both AC and DC can be checked with an ordinary tester, but the measurement of current (amperes) requires a special device, and it was not easy to measure before. In recent years, however, clamp testers that can measure current = amperes have become widespread, making it easier to judge the quality of the power generation system in this way. When you have a chance, please measure it.
