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BQ34110: Using BQ34110 for 24V 12Ah Lead Acid Batteries

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Part Number:BQ34110

Hello,

I want to measure the SoC and SoH of two 12V 12Ah Lead Acid batteries (connected in series to make 24V) using a micro controller like Arduino.

I have a few queries regarding the above configuration.

1) The reference design provided for BQ34110 and BQ34110EVM has BAT+, BAT- and PACK- connections. I assume BAT+ is the positive terminal of the 1st 12V battery and BAT- is the negative terminal of the 2nd 12 V battery. May I know which is the PACK- terminal connection?

2) I have a 24V lead acid battery charger. Which terminal should I connect them in the circuit to measure the charging current, etc.?

3) Do I need to have a external relay in the circuit to turn on the charger?

4) I was reading that the IC has to be configured and calibrated. Do I need to purchase the evaluation board to do the configuration/calibration process or is there any script that can used to do the configuration/calibration using the IC only?

5) Is there any Arduino library or any API using which can be used to get the SoC and SoH measurements?

Any sample circuit measuring SoC & SoH of 24V Lead Acid Batteries will be really useful.

Thank you!


BQ78350: high serial cell count + BQ78350

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Part Number:BQ78350

Hi

Is it possible or is there a FW version (or FW version that is planned to be released in the upcoming future) of the BQ78350-R1 controller that supports addressing several AFE in parallel (e.g. in case of working in a multi-cell configuration that contains more than 15 serial cells and requires working with two BQ769x0 components)?
Thanks!

BQ40Z60: BQ Studio Interface to end hardware

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Part Number:BQ40Z60

First, I'm new to BQ Studio, BQ40Z60 and even Li batteries.  The capability of this IC is a bit overwhelming, but it appears to be a cost effective solution for my project, so I am designing it in, planning to ignore about 75% of the capabilities of the chip.  Specifically, what I am doing is managing 4S generic 26650 LiNiMnCo cells.  There will be a wall transformer charge/power input and a permanently attached switchable load.  The portions of the IC that I need are: SMPS charging, including CC and CV and end of charge voltage/timer; cell balancing and fuel gauge.  I will also use the basic protection circuits, although things like overcurrent aren't real likely (the load is a PCB that the BQ40Z60 is on, and draws C/10.  Charging will probably be C/3).

Now to the question.  I see significant value in BQ Studio to help design and test the solution as well as program ICs for production.  But my board will be managing the I2C (OK SMB) bus itself, so that doesn't seem to bode well for using something like EV2300 or EV2400 to communicate with BQ Studio.  The product will contain (among other things) a USB based virtual COM port with a command parser.  How easy would it be to interface BQ Studio to that?  I have a fair degree of freedom in tailoring commands to the BQ40Z60.  The interface doesn't seem like it would be very hard.  The IC is a bunch of memory mapped registers, so if my parser understood a read and write command that got passed through to the IC from BQ studio, I would think that would cover everything.  Alternately, a command that did an SMB read and one for write, would be another way.  The only issues would be how data was represented, ASCII HEX, raw binary, etc.  I'm sure there is already a similar interface/protocol for the EV2300 or EV2400.

Maybe most of this has been done, and I just need to meet an interface standard or tweek a plug-in.  I'm not crazy about writing/modifying Windows code, as my tools are limited.  OTOH, I can do just about anything on the device side.  There is an ARM Cortex A9 at my disposal.

BQ40Z50-R1: What's the battery voltage accuracy of BQ40Z50-R1?

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Part Number:BQ40Z50-R1

Hi,

 

I have a question regarding BQ40Z50RSMR-R1: what's the battery voltage (total cells voltage) accuracy of BQ40Z50-R1 (after calibration)?

Please advise.

Thank you very much!

Joy

 

BQ40Z50-R1: Manufacturer Data/Info

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Part Number:BQ40Z50-R1

Hi,

Can someone confirm that the below are the same (in that I can read and write as desired) and that their values have no effect on the operation of the IC?

  1. 0x4040, Manufacturer Info A Length
  2. 0x4041-0x4060, Manufacturer Info Block A01-A32
  3. 0x4062-0x4065, Manufacturer Info Block B01-B04

Also, the subclass for #1 and #2 above is "Manufacturer Data" whereas that for #3 is "Manufacturer Info B". Is there a difference?

I am referring to Table 14-1 in the bq40z50-r1 Technical Reference, SLUUBC1C, http://www.ti.com/lit/pdf/sluubc1

Thanks,

Kwun

BQ78350-R1: General Questions on BQ78350-R1

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Part Number:BQ78350-R1

Hi,

I have been looking at the BQ78350-R1 gas gauge and BMCC to interface with either the BQ76930 or 40 series monitor. So to my understanding both of these IC’s work together for their intended use.

 

I wanted to build a prototype pack consisting of 18650s, and 8-10 cells would be ideal. A ~30 V nominal pack around 3Ah capacity is what I wanted to build and qualify with. As far as management options have gone I decided to go with this series of controller and monitor after researching what I could find on the website.

 

I first wanted to ask about guidance in selecting the best IC’s to do the job, if you have any other recommendations besides what I have listed I would appreciate hearing your concerns.

 

Furthermore, both data sheets for the IC’s layout examples of applications. So I see a schematic of something that looks like it should work but maybe is not guaranteed? For example in the R1 spec sheet I see on page 15 and 16 values for discrete components, resistors, capacitors, diodes etc with listed values with a BOM listed as well. Are these the exact components I need to implement such a battery monitoring system or are these values purely examples and are only for reference? If this is how it is supposed to be done that makes ordering and PCB layout easy or does a much deeper design need to be done?

 

Also what is the use for an EVM? Is this a pcb that is laid out with the IC’s already on and I can plug and play into my battery pack and go through the whole learning procedure? Just wondering what the usefulness of the EVM is and why to justify purchasing one. Say once I use an EVM to qualify I can monitor a pack, what are the next steps? Go about a ground up PCB design for permanent use using the same IC’s?

 

Also, I see in a reference design at  http://www.ti.com/tool/tida-00792 there is a microcontroller as well. So is a microcontroller something I need on top of these IC’s in the full management system for multiple chips to talk or is the microcontroller just to program over I2C or whichever protocol?

Thanks,

David

BQ27531-G1: Bq27531 program df.fs fail

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Part Number:BQ27531-G1

Dear all:
         I face a issue which can't re-program Bq27531EVM and my steps as below.

1. Use bqEVSW to program .senc default file and the resault is successful.
2. Use Bqstudio software to program customer's df.fs file. After this step that I can't re-program, it seems Bq27531 latch.

Althought change I2C address 0x16 or 0xaa via bqEVSW software, I read data at "Read I2C Data Block" and show error code=772.

May I have a solution to un-latch Bq27531?

Thanks!

BQ27531-G1: Bq27531 programs df.fs fail issue

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Part Number:BQ27531-G1

Hi Expert,

I am facing a issue which can't re-program Bq27531EVM and my steps as below.

1. Use bqEVSW to program .senc default file and the result is successful.

2. Use Bqstudio software to program customer's df.fs file. After this step that I can't re-program, it seems Bq27531 latch.

Although change I2C address 0x16 or 0xaa via bqEVSW software, I read data at "Read I2C Data Block" and show error code=772.

How can I recover the Bq27531EVM? Thanks!


BQ40Z60: Device documentation

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Part Number:BQ40Z60

I'm experiencing difficulty with the documentation.  Admittedly there is a lot to cover.  The data sheet focuses more on the hardware details and the TRM focuses more on registers and configuration, but there are gaps between the two that aren't covered.  Both documents sometimes read more like marketing pieces describing the extensive safety features (most of which I don't need).

The best part is section 9.2.2 of the data sheet, which gives design decisions and formulae.  However it is incomplete.  Here are some noticeable omissions:

1. ACP is connected to the external power through a resistor.  No mention is given as to appropriate values or why one would pick a value or whether this could be used for threshold detection.

2. ACFET has a 10 M resistor S to G in the worked out example, but not in the simplified one.  Presumably that prevents accidental turn on of the FET.

3. VFB (also called just FB some places).  I get it that at maximum charge voltage it should have about 1.22 volts on it, but is there a hard coded comparator involved, or is it just a matter of getting it in range and then setting registers appropriately?  I'm sure I will know the answer by the time I'm done, but I sort of need a board before I dive into the registers too far.

4. No mention is made of the gate resistor values for the non-SMPS FETs.  The worked out example uses 5.1 k, and I suspect it isn't critical, but are resistors even needed at all?  These are FETs.

5. Nothing is said about the BAT pin, other than it powers the IC unless the batteries are so low it can't (which wouldn't have been my preference.  I'd have rather powered the IC from the adapter any time it was present).  The example shows a 10 ohm resistor and a shottkey diode, with a note to replace the diode with another 10 ohm resistor in single cell applications (presumably because of voltage drop), but no mention as to why either is needed or how to determine the value.

6. There is a lot of information in various documents about charge balancing, ranging from using just the internal (200 ohm) FET resistance to 100 ohm series resistors or 1000 ohm or even 10K or forcing quick balancing with FETs (which adds complexity).  But there really isn't much that says what is necessary in typical usage.  So I have 5 AH cells that will charge in about 3 hours.  Given the cell to cell variability I would typically encounter (or some tolerance spec) what formula would suggest an appropriate value.

7. Related to item 6, there are comments about filtering the feedback that comes through the VC pins.  Obviously if there are no resistors (a tempting option for a minimalist solution) no filtering is possible.  One source (for a different IC) suggests a time constant for such filtering, but the BQ40Z60 does not nor give any guidance.  I'm assuming the 100 ohm resistors and 0.1 uf capacitors in the example are appropriate.

8.  For both SHR and SR, there is mention of 0.01 ohms.  There are also some ranges and limits mentioned.  It appears that these differential sensing circuits are used in some cases scaled by register values, but may also be used in other cases with fixed limits, so the size of the resistor should be application specific.  However, I can't find any specific information about such, or even appropriate scaling constants for the registers.  I'm sure the latter exists, but it is buried beneath information on how to protect the cells from events that won't happen in this design.  It would be helpful if a paragraph were devoted to the things these two sensors are used for and how to compute an appropriate resistor value and set related registers--all in one place.

9.  The TS lines can be used to drive LEDs (with or without thermistors).  I probably won't use thermistors in this design, as my charge and discharge currents are below 1C.  Can I use the pins to directly drive LEDs?  Or must I buffer them with FETs as shown in the example?  That adds significant complexity to the design (you get the idea that I'm looking for a minimalist solution?  That's why I chose a single do-everything IC).  I couldn't find any information about the drive strength or even polarity of the pins as outputs for LEDs.  I did manage to find some information in the TRM about configuring registers to support LEDs.

The material in 9.2.2 is excellent as far as it goes, but it really needs to extend to about every pin and component on the board.  The example schematic is not the best help, either, as it is for the eval board, which incorporates almost every possible feature one could imagine, many of which are never talked about.  There are even FETs in it for purposes I don't even know.  Alternatively, maybe there just needs to be a third document, like the TRM, but focused on hardware design decisions.  A tutorial that says here is how to use this IC in a minimal configuration (like the simplified schematic, but with enough parts to work), and here is how to add features, one at a time.

Thanks,

Wilton

BQSTUDIO - I want to either disable autodetect, or switch between connected devices easily

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BQSTUDIO - I want to either disable autodetect, or switch between connected devices easily

I have both a TI Power Management device bq25895M, and a fuel Gauge, bq27742-1, working and sharing the I2C bus in a new design. 

To switch between them in bqStudio, I must relaunch BqStudio with the usb disconnected. This blocks the auto-detect, and then I re-plug the USB after manually selecting the target device.

Questions: 

1) Is there an easy way to switch between target devices, once bqstudio is running

2) Is there a way to disable auto-detect in bqstudio launch?

Most gratefully,

Michael B

Amp Hour tracking

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I would like to add tracking of charging/discharging in a new design via USB. Basically, instead of relying on tracking the voltage of batteries with an integrated battery charger, I would like to track the voltage/current to an external battery bank to track energy level. Is there a device made by TI that could be implemented to track battery levels via USB charge and discharge? The battery level could be via LED's, LCD display or via available I2C communications. ANy ideas would be great. Thanks!

BQ34Z100-G1: Charge termination - Accumulated change in capacity calculation

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Part Number:BQ34Z100-G1

BQ34Z100-G1 charge termination indication is explained in SLUSBZ5B as revised July 2016, section 7.3.11 but 1(b) gives a puzzling description of how the threshold for accumulated change in capacity can be calculated. The reference to 0.25 mAh presumably refers to whatever value is stored in flash starting at subclass ID 36 and offset 2 which is labelled “Min Taper Capacity” and said to have a default of 25 mAh (not 0.25 mAh). The reference to Taper Current Window must refer to the flash location of the same name (subclass ID 36 and offset 6) for which the unit seems to be seconds (not hours). A worked example of a calculation for any accumulated change in capacity threshold would therefore be helpful, especially to people not using the evaluation hardware or software. Could anyone spare the time to provide one, please?

BQ35100: BQ35100 SOH value drops to 0% within a few hours when using SOH mode but the batteries are still full

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Part Number:BQ35100

Each time we take a SOH measurement the value drops by 2% of full scale, but the batteries have not actually drained by 2%.

We are using the BQ35100 chip.

The chip is loaded with the default BQ35100 image from Texas Instruments v1.02 bld10, but with the following changes...
1)  The CC offset, Board Offset, Current, and Voltage are calibrated for our board.
2)  The chem ID 0607 is loaded into the device.
3)  The gauge is configured for EOS mode.

Our system consists of two pieces. 

1)  A battery pack containing two Tadiran TL-5930 cells in parallel for a total of 36000mAh of capacity.  The nominal battery voltage is 3.6V, but may dip as low as 3.0V at cold temperature.  In series with the batteries there is a 200milli-Ohm resistor inside the battery pack that is part of a separate protection circuit.

2)  A circuit card that sits in another enclosure, apart from the battery pack.  Our card will function properly with input voltage from 1.8V to 5.5V.  The BQ35100 REGIN pin is sourced from a constant 3.3V that comes from a Texas Instruments TPS63030.  The BAT pin is tied directly to the output of the battery pack.  We are using a 100 milli-ohm sense resistor.  The peak current is around 50mA, and our sleep current is under 1mA.  The system is deisigned to momentarily support loads of a few hundred mA, but that is not happening during this test.


The circuit card normally sleeps for around 8 seconds.  Wakes up for 200ms, and then goes back to sleep.  The process repeats indefinitely.

Here is the software process we are using to read the SOH values.
1)  Assert the GE pin.
2)  Wait at least 4 seconds.
3)  Send GAUGE_START
4)  Wait for at least 10 seconds.  The circuit card will have been asleep and awake for at least part of those 10 seconds.
5)  Send GAUGE_STOP
6)  Wait at least 4 seconds.
7)  Poll the G_DONE bit at a rate of not more than once every 4 seconds for up to 1 minute.
8)  Wait at least 4 seconds.
9)  If the G_DONE bit is set within one minute then read the SOH value from the gauge.


If I put a new set of batteries into our pack and send the NEW_BATTERY command.  The SOH measurements read 98% after the first measurement cycle, but falls to 0% within a few hours.  With the above specifed power useage profile the batteries should last over a year.

Using the same set of batteries.  If I send the NEW_BATTERY command again.  The process will repeat.  The gauge reports 98% and then slowly decays to 0% in a few hours.

Here are my questions...

1)  Will the 200mOhm resistor affect the accuracy of the EOS algorithm?
  a)  If so is there any sort of settings change that could be made to either calibrate it out or minimize its effect on the measurements.  Many practical systems will include some resistance due to cabling or fuses that must occur prior to the gauge, there must be some way to calibrate them out.

2)  Given the above information, is there some setting in the image file that I should be changing?

3)  Assertion of the GE pin is not in any way synchronized to peak current draw.  We guarantee that both high and low current draw will occur during the measurement cycle, but we don't guarantee which one will occur first.  Is this a problem?

As a side note:  its too bad this chip doesn't have a register where I could program a time between measurements and a measurement duration and then just have the chip automatically wake up and take the EOS measurements.  If it did then we could just read the SOH values without all the extra work of managing when to turn the gauge on and off (I could live with the extra 15uA of standby current).

BQ30Z554EVM: Unseal bq30z554

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Part Number:BQ30Z554EVM

Dear community,

We are repair service for laptops and have an Asus N550J in the repair.

Until we have been waiting for the spare parts for this laptop, the battery C41-N550  has discharged and will no longer start.

Microcontroller bq30z554 is sealed and  can not be calibrated. 

It would of course be easy to order new battery, But for engineers it is not an option :)

The battery has only ran 81 cycls ...

I would like to know there is a way to unseal the controller, or we should order new IC?

With default unseal code it does not work,

I have heard there is a master code for such cases?

Any help is welcome.

Thank you in advance!

BQ27742-G1: I2C Communication without level translator

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Part Number:BQ27742-G1

Hello,

I am using BQ27742-G1 fuel gauge for monitoring a battery pack of two 18650-25R cells. The fuel gauge is directly powered by the batteries whose potential may be at different levels from 3.2V to 4.2V. However the I2C communication from the host is at only two levels i.e. 0 V and 3.3V . I was using a level translator (TSX0102DQER) for converting the voltage levels and for protecting the fuel gauge when battery is not present and 3.3V is present, or vice-versa.

However I am planning to eliminate the level translator and directly connect the I2C lines to the gauge even though the voltage levels maybe different. So my question is will communication be successful in this way? And will there be any damaging effect to the gauge in a situation when the battery may not be present so the gauge is not powered but the I2C Clock and Data pins will be at 3.3V level? I am doubting it because the gauge is not powered, yet there is 3.3V potential at its input pins. Please help.

Thank you.


BQ34Z100-G1: Datasheet recommends an unusually high resistor for the voltage divider at the BAT input

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Part Number:BQ34Z100-G1

Hello. We have an issue when measuring higher voltages with this chip. On the BQ34Z100-G1 datasheet (p.36) the following is recommended for the external voltage divider: "The bottom leg of the divider resistor should be in the range of 15 KΩ to 25 K, using 16.5 KΩ". This results in a high resistor value for the upper leg as well. However, with so high resistor values, we face problems with humidity and electrical noise. Thus we would like to use much smaller resistors for the external divider, in the range of hundred Ohms (current consumption is not an issue).

So the question is: is it ok with this chip to use, eg. 100 Ohm for the bottom leg of the external divider that drives the BAT input?

Thank you in advance

BQ20Z45: .senc file and exporting data flash image for production

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Part Number:BQ20Z45

I have a bq20z45 EVM and using the bqEZ tab of the EVM software.  I have done all the calibration and cycle (charge discharge).  I got to the last step and the .dfi file was created and downloaded with no errors.  Max Error is at 1% and cycle count went back down to zero.  Hoever I am not sure what to do next.  The manufacturing golden pack instructions say to write 0f00 to word 00 but I get an error when doing that write - VBUS_BAD_PEC.  also not sure where the .senc file is stored or how to access it (along with chemical ID).  this is referring to doc SLUA334b sheet 2 section 3, step 5. 

BQ34Z100-G1: Gas Gauging 'Quit Current' setting when trickle charging?

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Part Number:BQ34Z100-G1

Hello,

We have an application with 6S1P NiMH 12000mAh. When charge termination is detected,~100mA is applied. Should we set 'Chg Current Threshold' below the trickle charging rate so that the gas gauge thinks it is still charging while trickle charging? Should 'Quit Current' be above 100mA so that it will go into relaxation mode when trickle charging for OCV readings and Qmax updates?

Sometimes the pack is trickle charging for 2-3 hours past charge termination. If the pack does not enter relaxation mode this long after charge termination, could this have detrimental effects on Qmax and RA tables?

Thanks,

Allan

BQ27520-G4: put RC filter between BAT pin and PACK+

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Part Number:BQ27520-G4

Hi Team,

My customer considers to put RC filter between BAT pin and PACK+ of Li-ion battery.
He said battery voltage dropped when heavy load transient was occured in his system and wants to damp the voltage variation from gas gauge.
Is it reasonable approach?
I would like to have your comments.

Best Regards,
Yaita / Japan disty

BQ27220: Configuration of BQ27220

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Part Number:BQ27220

Hi E2E Team,

Please find the attached configuration file for BQ27220. Please go through it and let us know if any other changes required before taking the logs.
Below mentioned is the current consumption of our device.
Inline image 1
 We need to take charging and discharging logs at 5°C, 30°C and 45°C  for different values of current correct?
(Please visit the site to view this file)

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