Battery Monitoring with Crank-Check™ Technology

 
Today's conventional battery testing technologies, such as load testers and conductance testers, fail to answer the single most important question about a starting battery: How well is this battery performing the specific job of starting this engine? Conventional conductance methods produce an absolute value that does not indicate how effective the battery is at doing its job or when the battery will stop doing its job. This limitation led to the development of our Crank-Check™ technology, which uses the actual engine starting sequence to evaluate battery performance.

Crank-Check captures the voltage profile of the battery during the starting sequence. Figure 1 (at right) shows a typical voltage profile of a normal, healthy battery during the engine starting sequence. P1 indicates the floating voltage of the battery; P2 shows the point of solenoid engagement; P3 indicates the point of starter motor engagement; P4 shows the engine being cranked by the starter motor followed by the engine start; and P5 refers to the point after the starter motor is disengaged and the battery is starting to be charged by the alternator.

By comparing various points on this profile, Crank-Check determines the health of the battery performing its job or cranking the engine. Of particular importance to starting performance is the difference between P2 and P3. Figure 2 shows the profile of a weaker battery with respect to its starting load. Figure 3 shows a very weak battery. This profile indicates an imminent cranking failure situation.

An important point to realize about using a voltage profile analysis of a starting battery is that you do not need to know the battery specification, rating, or size. Nor do you need to know anything about the motor. The voltage profile indicates the relative performance of that battery starting that engine at that time. This means that a voltage profile analysis can be used on any size battery or engine. Gone are the days of conversions or looking up reference values.

The Crank-Check voltage profile analysis provides a highly accurate and relevant snapshot of battery performance. The result immediately and directly answers the question posed above: How well is this battery performing the specific job of starting this engine? The AA series of battery test tools combine Crank-Check testing with Large Pulse Resistance (LPR) [link to LPR test technology] testing to provide a comprehensive analysis of battery and starting system health.

Battery Monitoring with Crank-Check

Crank-Check has proven to be a great starting battery test technology, and it is even better when used to monitor a battery over time. Batteries naturally lose capability as they age and are used (and perhaps abused). As they lose capability, their starting voltage profiles change. By monitoring a battery's starting performance over a period of time, we can calculate how fast the profile is changing and predict when in the future that battery is likely to experience a cranking failure. Figure 4 (below) shows how failure can be predicted by measuring how P3 is changing over time. This capability can be invaluable in fleet or mission critical vehicle applications, where preventative maintenance has a high value.

The Battery Bug Starting Battery Monitor (BB-SBM) series uses Crank-Check to evaluate the performance of the battery at every start. All BB-SBM models display the cranking health and remaining life of the battery at all times, and will sound an alarm when it is time to replace the battery. To learn about our starting battery monitors, look more closely at the BB-SBM Series.