TORKEL900 series battery discharge test systems
High discharge capacity
Discharge up to 220 A, offering the possibility to shorten test times. With additional TORKEL units or extra load units (TXLs), higher currents are available.
A complete standalone discharge test system
When used in conjunction with the BVM battery voltage monitor, the TORKEL will measure battery capacity as well as individual cell voltage data throughout the entire discharge test.
Real time monitoring of test results on screen
With BVM connected you can spot weak cells and prepare in case they need to be bypassed to continue test.
On-line testing
Eliminate the disruption of taking the battery out of service, discharging, re-charging, and returning to service, no need for a backup battery bank.
Safety in all details
Automatic detection of blocked airflow to prevent overheating, spark-free design, and emergency stop all contribute to make sure the discharge test is performed as safely as possible.





About the product
The TORKEL900 series of battery discharge test systems are Megger’s fourth generation of battery discharge analysers. Discharge testing is the only test method that provides a comprehensive insight into battery capacity, and is therefore an essential part of vigorous battery maintenance programmes.
Tests with the TORKEL900 series can be conducted at constant current, constant power, constant resistance, or in accordance with a pre-selected load profile. What’s more, if you connect the BVM battery voltage monitor to a TORKEL900 unit, the TORKEL becomes a complete standalone discharge test system.
With the TORKEL900 series, you won’t need to disconnect the battery from the equipment. The TORKEL900 units use a DC clamp-on ammeter to measure the total battery current while regulating it at a constant level. If the voltage drops to a level slightly above the final voltage, the TORKEL issues an alarm and if there is a risk of deep discharging the battery, the TORKEL stops the test. All results are stored in the TORKEL and can easily be transferred to a PC via a USB drive.
Additionally, testing times are much shorter with the TORKEL900 series, thanks to their high discharge capacity. Discharging can take place at up to 220 A, and if higher current is needed, two or more TORKEL units or extra load units (TXL) can be linked together.
The TORKEL900 series has three models available: 910, 930, and 950, depending on the maximum current (up to 220 A), voltage (up to 500 V), and functionality required.
Technical specifications
- Data storage and communication
- Internal memory
- Data storage and communication
- USB
- Power source
- Mains
FAQs
A load/discharge test is the only definitive way to assess a battery’s capacity. When used regularly, discharge testing can be used for tracking the battery’s health and actual capacity and estimating the remaining life of the battery. During the test, we measure how much capacity the battery can deliver (i.e., current multiplied by time, given in Amp-hours (Ah)) before its terminal voltage drops to a level signifying that the discharge is complete. This terminal end voltage equals the battery cells’ end of discharge voltage x the number of cells. For example, suppose the end cell voltage is 1.75 V, and the battery has 60 cells. In that case, the test stops when the terminal voltage reaches 60 x 1.75 V = 105 V. Throughout the test, the current is maintained at a constant value. If the battery reaches the end of discharge voltage at the same time as the specified test time ends, then the battery’s measured capacity is 100 % of the rated capacity. Conversely, if the battery reaches the end of discharge before 80 % of the specified test time has passed (e.g., within less than 8 hours of a 10-hour specified time), you should replace the battery.
At least a couple of times during the discharge test, you must measure the individual cell voltages. The most critical time for these voltage measurements is at the end of the discharge test to find the weak cells. It is also imperative that the time, or the current, during a discharge test is adjusted for the battery’s temperature. A cold battery will give less Ah than a warm one. Temperature correction factors and methods are described in the IEEE standards.
Batteries can also be tested in a shorter time than their duty cycle, for instance, in 1 hour. If you elect a reduced test time, the current rate has to be increased. The advantage of this approach is that a battery’s remaining capacity is greater at the test’s conclusion than that for a full-length test. A battery with less capacity is inconvenient and possibly very expensive to rectify in time, resources, and money.
IEEE Recommended (Maintenance) Practices cover the three main types of batteries: Flooded Lead-acid (IEEE 450), Valve-Regulated Lead-acid (IEEE 1188) and Nickel-Cadmium (IEEE 1106). Generally speaking, maintenance is essential to ensure adequate backup time. There are differing levels of maintenance and varying maintenance intervals depending upon the battery type, site criticality, and site conditions. For example, if a site has an elevated ambient temperature, then the batteries will age more quickly implying more frequent maintenance visits and more frequent battery replacements.
Battery systems are designed to provide backup supplies during power outages. Since a discharge test is nothing other than a simulated power outage, there is no risk of battery damage. Batteries can normally be deep discharged (that is, discharged to the manufacturer’s end-of-discharge voltage) between 100 and 1000 times, depending on the type of battery. Using a few of these discharge cycles for capacity testing has a negligible effect on overall battery life. Nevertheless, there is no reason to carry out discharge testing more frequently than recommended by the relevant standards.
Yes, with the optional CT, the TORKEL will automatically sense and regulate the discharge current even when the batteries are connected to their normal load. Most users choose to make an 80 % discharge test if the battery is to remain on-line, thereby ensuring that there is still some backup capability remaining at the end of the test.