Support for the BITE3 battery impedance tester
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This means that the battery system has internal noise.
What you can do:
The system can still be tested with the BITE3 using the optional CT. In the BITE3 settings menu, set the CT for “Impedance” mode. Connect the CT to the BITE3 and around any suitable location within the string being tested. The BITE3 will use the measured current through the CT and the voltage drop caused by the system noise, measured via the BITE3 probes, to calculate the correct impedance.
This is what is expected. This message indicates the ripple current is low and the batteries are in float mode. If this is the case, click YES to proceed with the impedance testing.
Note: If the ripple current exceeds 5 A per 100 Ah battery capacity, then you have found a problem that needs to be corrected.
Note: If the float current reads high then stop the testing; the batteries are not fully charged and the readings you get will be misleading.
The BITE3 can automatically detect the difference between a cell and a strap. If the unit displays “Confirm Strap”, this means the unit does not recognise a cell or a strap. If you are measuring a strap then just pull the trigger. If you are measuring a cell, you do not have a good connection.
This can be an indication of a fundamental current on the battery string. The BITE3 automatically detects cells and straps by measuring the floating voltage on the BITE probes. If the voltage goes high, this indicates the probes are across a cell. If the voltage goes low, this indicates the probes are across a strap. If enough noise or fundamental current is on the string, then the unit may not be able to identify if the probes are across anything.
What you can do:
Place the unit in the “spectrum analyser” mode and place the probes across a strap (you may need to place the probes close to one another on very noisy systems). If the spectrum analyser indicates fundamental current is present on the string, stop. Turn the charger off and see if the problem clears up. If it does, then the charger has an open rectifier and needs repair. If it does not, there is a short that is allowing fundamental current to get on the string. This must be corrected as it will lead to overheating of the batteries.
The unit automatically detects the type of lead set connected. If this message appears, first check the lead connection to the unit. If this is good, then try a different set of leads, if available. If this does not work, contact customer service.
The Reverse Polarity message indicates that the probes are backwards.
What you must do:
Reverse the probes! DO NOT PULL THE TRIGGER until you have reversed the probes. Pulling the trigger will blow the fuse in the unit.
This is usually the result of a blown 1 A (Slo Blo) fuse in the side panel. To test for a blown fuse, place both BITE probes on the same terminal of a battery. This will act as close as possible as a zero ohm connection and should yield a very low impedance measurement. If the measurement indicates out of range impedance values, it is very likely that the protective fuse has been blown.
There could be two causes for this:
- the leads got across >19 V
- the two field-effect transistors (FETs) on the power board have shorted.
What you can do:
It may be possible to replace the fuse, but if the FETs are shorted, the unit will need to come in for repair. If FETs are shorted, it’s more likely that you just won’t be able to read battery impedance.
There may be several reasons why you’re not receiving a reading or the reading is erratic:
- the impedance value you are trying to measure is too high
- the fuse in the unit is blown
- there is damage to the lead tips
What you can do:
- Check the fuse and replace it if it is blown
- If the fuse is ok, clip the leads of the unit together and take a measurement. If the “out of range” error is displayed, there is a problem with the BITE3 and you will need to contact the authorised repair centre. If the unit does take a measurement, the impedance of the cell you were originally trying to measure is too high.
- Finally, lead tips can break off inside shafts on the 36616 lead set, and often remain stuck in the shaft and not visible as damage. If this is suspected, please return the instrument to the Megger Repair Department.
If you see a “system error” when powering up, it’s likely that there is damage to the processor.
What you can do:
The PC104 module, where the firmware is located, has probably been damaged, likely by heat. The unit must be sent to an authorised repair centre for repair.
Interpreting test results
The real value in battery testing lies in the trending of data to determine if problems are imminent or farther out. The following table offers general guidelines to evaluate impedance and strap resistance measurements. Over time, BITE3 users will establish their own percentage deviation warning and alarm values. It’s strongly recommended to use the software provided with your equipment to keep all the historical data for each of the strings under test. The software includes several charts - including warning and alarm criteria - that will facilitate the trending and analysis of the data.
User guides and documents
Software and firmware updates
Since it's original release, the BITE 3 has seen 3 different variations of processor board. This complicates the update process just a bit. Before downloading an update, please turn on your instrument and navigate the menus to "System", "About". The first entry is Version. The First field of the Version of you instrument must agree with first field of the download version. i.e. Your instrument currently is at Version 188.8.131.52 then you would use update "Firmware 184.108.40.206". The download file will have the name "BITE220.127.116.11.2.update". Each update begins with "BITE3" a period and the update version number in this case "18.104.22.168" a final period and the word "update".
Save the download to a place that you will be able to easily navigate to. Then use PowerDB to update the BITE3.
For more information, please contact Andy Sagl ([email protected]) at Megger Valley Forge at 610-676-8528. PowerDB software for the PC now supports BITE 3.
BITE3 Excel Upload Utility
The BITE3 is fully supported by the PowerDB Software. The PowerDB Lite software is provided at no charge and can be downloaded from this web site. However, if you choose not to utilise PowerDB Lite for your data maintenance and analysis needs, a Microsoft Excel template file is provided that will allow you to upload test data in the BITE3 to the spreadsheet. Once the data is uploaded to the spreadsheet, you are free to use any tool in the Microsoft Office suite to analyze, archive, and/or export your data.
We have noted that some versions of Microsoft Internet Explorer rename the update file to a dot zip file extension (.zip). Mozzila FireFox works correctly leaving the file extension as "dot update" (.update). If this happens to you, please modify the file extension from (.zip) back to (.update) before saving. Thank you for your understanding.
Yes, Megger offers a variety of probes and other accessories for the BITE3 to make your testing easier. Check the BITE Accessories data sheet or contact Megger to find the best fit for your application.
The probe tips are spring-loaded to penetrate oxide coatings and No-Ox greases to make a solid connection. Even though the tips are designed with ruggedness in mind, spare tips have been included with the instrument. Should a tip become damaged, simply pull the tip using pliers and replace it with a new one. The tip should be snug, not loose or overly tight.
Even though the correlation between battery capacity and impedance is not mathematically perfect, an increase in impedance is an excellent indicator of battery health. Megger has found that, for flooded lead-acid batteries, a 20 % increase in impedance generally indicates that the battery capacity has declined to about 80 % of its initial value. For valve regulated lead-acid (VRLA) batteries, the corresponding impedance increase is closer to 50 %. When these increases are observed, cell replacement is justified.
To review the readings, simply scroll up/down the screen. To return to testing, scroll to the last readings and start taking measurements.
Yes, there are many tests that can be performed on a battery string. Specific Gravity and discharge testing are two prime examples of additional tests to perform. The truth is, no single test can be used to determine if a string is good or bad. To find out more about additional testing and maintenance, check out the Application Note: Recommended Battery Maintenance Practices.
In short strings (e.g., less than 40 cells), it’s advisable to replace the entire battery when between three to five cells have been changed. For longer strings, whole battery replacement is advised when more than 10 % of the cells have been changed.
When performing an impedance test, or any ohmic test, the batteries must be fully charged. An impedance test is a relative test. It is comparing the present measured value to past values. If the batteries are not fully charged, then the measured value will not be the same as that for a charged battery. Therefore, you cannot compare the present value to past values, because there is no common state of charge of the battery.
To retest a cell (sometimes called a jar) or a strap, simply scroll to that cell or strap and press the right side of the cursor control pad. Retest the cell or strap. To return to the normal test mode, press the left side of the cursor control pad and scroll to the last cell or strap and continue testing.
The best frequency for impedance testing depends on the battery type, the site conditions, and previous maintenance practices. The IEEE 11888 standard for VRLA batteries recommends, for example, that a baseline impedance measurement is made six months after the battery has been put into service, and that further impedance measurements are made at quarterly intervals thereafter. For NiCd and flooded lead-acid batteries, Megger recommends impedance testing at six monthly intervals. Impedance measurements should also be made immediately before carrying out every capacity test.