In the world of automotive batteries, system testing is checking the condition of your vehicle’s 12-volt (or 24-volt) system. This includes the battery (or batteries), charging system (alternator), and starter motor.
To conduct a system test, you need a system tester. This functions in much the same way as a standard battery tester, in that you connect the clamps across the battery terminals and run the tester. However, it also tests the condition of the starter motor and alternator under different loads.
Learn more about the process and why it’s important on this page.
What does system testing reveal?
System testing is a crucial aspect of ongoing battery maintenance. That’s because sometimes, the problem isn’t the battery itself. Tests may reveal the battery to be perfectly healthy. However, underlying problems with the alternator or starter motor may still lead to 12-volt electrical issues.
For example:
- A malfunctioning alternator may overcharge or undercharge the battery. You need to know this before replacing a poor-performing battery. Otherwise, you’ll find the same discharging problems repeating with the new battery.
- A malfunctioning starter motor may demand too much current or have another underlying fault. As such, even though the battery and alternator may be in good condition, the vehicle doesn’t get sufficient cranking amps.
How do you do a system test?
One of the best products for system testing is the Midtronics CPX-900. It displays simple on-screen instructions and is specially built for comprehensive tests, including on 24-volt systems.
And although system tests vary slightly from vehicle to vehicle, here’s how to use your CPX-900 to carry one out:
Do a battery test
- Connect the test cables across the battery (or battery pack).
- Enter your user ID.
- On the CPX-900, navigate across to System Test and press Select.
- Enter the fleet ID/VIN.
- Select Car/LCV if you’re running a standard car or van 12-volt system. Select Bus/Truck if your vehicle has a 24-volt or higher battery pack system. Press Next.
- Choose the number of batteries in the pack, if prompted.
- Choose the battery voltage. In most automotive cases, this will be 12 V. Then, select the battery chemistry (regular flooded/FLA, AGM Flat, AGM Spiral, or EFB).
- Choose the battery rating unit (EN, JIS, DIN, SAE, IEC, or CCA) and enter the battery’s rating.
- When prompted, point the tester at the battery one more time to take the temperature.
- The CPX-900 then conducts the battery test. You’ll see the results on screen.
Test the starter
- Press Next and continue with the starting system test.
- When prompted, start the engine.
- The CPX-900 provides an immediate result, displaying the cranking voltage.
Test the alternator
- After the starter motor test, press Next.
- Choose whether or not you’re using an amp clamp.
- The unit goes ahead with an alternator test, at idle rpm with no loads.
- When this test completes, hit Next. The screen prompts you to raise the rpm (still with no extra loads).
- Hold the rpm at this speed until the unit gives you your next instructions.
- When prompted, let the engine idle. When the screen tells you, turn on the relevant loads: blower fan and headlights.
- Hit Next and let the unit test your system at idle with loads.
- When prompted, rev the engine to the appropriate speed with the loads still on.
- When finished, let the engine idle, and press Next.
- The tester will continue analysing. You will eventually be told to turn off all loads and then turn off the engine.
Results
You can now view the results of each of your three tests.
The simplest way to do this is via ROBIS. Your CPX-900 has built-in wifi and is compatible with ROBIS. ROBIS makes it easy to store, compare and analyse your system results. Your results can be automatically stored alongside the VIN, technician ID, and date and time.
You can also view your results via a printer. Hit Print on the CPX-900. Ensure your IR port points directly at the printer.
You’ll then have a printed result for this test session, including the results from the battery test, starting system test, and charging system test. Your technicians can read these test results on paper and store the results with the vehicle’s documentation.
Get your Midtronics CPX-900 from Rotronics
Rotronics is your go-to provider for battery maintenance solutions. As 12-volt, 24-volt, and EV battery specialists serving the UK, our line-up of products includes trusted brands like CTEK and Midtronics. We help you develop and maintain an ongoing battery maintenance solution that works for you, reducing downtime and non-starts. All that means your workshop staff can focus on what they do best.
System testing can provide a deeper understanding of a vehicle’s condition. Get in touch with us today to source a from our team of experts. We help fleets to avoid downtime, and help fast-fit and dealership operations to identify underlying issues with customer vehicles, leading to more work and a more comprehensive repair.
