MEGGER 246002B BITE2 BATTERY IMPEDANCE TESTER 120V 60HZ

Megger BITE 2 Description

Determines the condition of lead-acid and nickel-cadmium cells up to 7000 Ah. An advanced feature set has been developed that includes Pass/Warning/Fail calculations based on a user-entered baseline value, advanced printing functions and more. The instrument works by applying a test signal across the battery string while on-line, then calculates impedance based on simultaneous measurements of current and resulting voltage drop of each cell/jar. It also measures dc voltage and interconnection (strap) resistance to help determine the overall condition of the entire battery string's electrical path from terminal plate to terminal plate.

In addition, it measures ac ripple current which, if too high and over an extended period of time, can damage the battery by heating it (an increase of battery temperature by 18°F/10°C will halve the life of lead-acid batteries). Battery manufacturers generally recommend a limit of 5A of ac ripple current for every 100 Ah of battery capacity. The first measurement that the instruments take is ac ripple current which should be trended.

The receiver stores the readings in its internal memory. These measurements, along with other maintenance data such as ambient and pilot cell temperatures and ac ripple current, assist in determining the overall condition of battery systems.

Unlike load cycle testing that involves substantial downtime and repeated discharges, using this instrument requires no battery discharge, nor does it stress the battery in any way compared to other techniques. With a test time of less than 15 seconds for each cell and intercell connector, one person can easily, quickly, and precisely measure internal cell impedance, dc terminal voltage and intercell connection resistance without taking the battery system off line and evaluate charger condition also.

Features

• Determines condition of lead-acid and NiCd cells up to 7000 Ah
• On-board Pass/Warning/Fail indications
• Robust, repeatable instrument
• On-line testing
• Checks charger condition by measuring ac ripple current
• On-line testing requiring no downtime
• Enhanced printing and memory functions
• Calculates impedance automatically and stores results for on-site review
• Requires no battery discharge
• Receiver can download stored data to PowerDB software for quick, easy analysis
• Reduced test time: less than 3 seconds for each cell
• Measures impedance and dc voltage values for all lead-acid and nickel-cadmium cells up to 7000 Ah
• Stores more than 2000 sets of readings in up to 300 tests
• Checks charger condition by measuring ac ripple current
• PowerDB LITE allows data to be stored and allows custom reporting (ideal for NERC & FERC requirements)

Specification

Receiver

The battery-operated receiver incorporates the potential leads, clamp-on current sensor, and data storage capabilities. It stores more than 2000 sets of data (cell impedance, cell voltage and interconnecting strap resistance, date and time stamps) in up to 300 tests. It also allows for printing the active test for easy review and retest. Selective printing of any test and deleting oldest tests are now included features to maintain in memory the most critical tests. At any time while performing a test, the operator can review the current test results by using arrow keys and scrolling back through the active test screen.

One additional feature of the receiver is that if you are called away while in the middle of the test, simply shut down the instrument and it will remember where you left off in the test.

The clamp-on current sensor is connected to the receiver during testing and clamped around a convenient intertier or intercell connection within the loop created by the transmitter's current source leads and the battery string. If the intercell or intertier connection consists of more cables than the diameter of the clamp-on current sensor can encompass, the receiver has a split-strap function.

Transmitter

The transmitter provides the capacitively coupled ac test signal to avoid transients on the dc buss and applies it to the cells under test via the source leads. The BITE2 transmitter has an LCD and built-in receiver charger. Data, measured and stored in the receiver can be exported to a PC.

Test Procedure

The BITE2 works by applying a capacitively coupled ac test signal across the battery string while on-line. The receiver and potential probe are placed at the cell terminals to measure the signal and resulting voltage drop for each cell/jar. During each measurement, impedance is calculated following Ohm's Law, displayed on the LCD and stored. The instruments also measure, display and record dc voltage and interconnection (strap) resistance to help determine the overall condition of the entire battery string's electrical path from terminal plate to terminal plate. The also measure ac ripple current, a charger parameter.The receiver stores the readings in its internal memory. These measurements, along with other maintenance data such as ambient and pilot cell temperatures and ac ripple current, assist in determining the overall condition of battery systems.

Interpretation of Readings

Data produced by the BITE2 can be interpreted in several modes: instantaneous, short-term and long-term time frames. PowerDB makes data analysis fast and easy.

Instantaneous Interpretation

The operator can enter a baseline value from either the impedance measurements obtained at commissioning. The percent changes from baseline for warning and fail levels are entered, but 20% and 40% are the default settings. The LCD on the receiver will display the status of the cell for a few seconds before proceeding to the next cell. The status of each cell/jar will be printed on the Battery Analysis Report.

Short-Term Interpretation

Impedance readings for individual cells can be used in the short term to compare with the average impedance readings for the entire battery string. Individual cell values with deviations of more than ±15% for flooded lead-acid, ±35% for VRLA, and 50% for NiCd cells from the battery string average typically indicate a problem with that cell.

Long-Term Interpretation

Impedance readings for the entire battery can be used in the long term to determine replacement criteria. Battery cell impedance values should be recorded and compared to previous readings to determine the position of the cell on the curve of impedance versus cell life. Based on experience, a variation of ±20% from baseline for flooded lead-acid, ±40% for VRLA and 50% for NiCd cells indicate significant change in the electrical path to warrant serious evaluation of the condition of the battery system.

Applications

• Electrical power generation plants
• Substations: utility, railroad, industrial
• Telecommunications facilities: CO, Wireline, Wireless, MTSO
• UPS systems
• Railroad: signals and communications, substation
• Aircraft power supplies
• Marine, military