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BQ34110EVM-796: BQ34110

hedley davidson
Prodigy 50 points
Part Number: BQ34110EVM-796
Other Parts Discussed in Thread: BQ34110, BQSTUDIO, EV2400, , BQ34Z100-G1

1. We procured the EVM

2. It now seems as if we have to purchase the TI 2300 or 2400 USB-> I2C interface to work with the eval software

3 Question -

(A) Can any USB-> I2C interface be used ?  and if not 

(B) How will we get our final application to talk to the BQ34110 in the final product . ? 

as if not we would be forced to purchase your interface for each end product which blows the price point out of the water

Regards

Hedley Davidson

CEO

Cynaps Technologies 

hedley@cynaps.co.za

  • 0
    TI__Mastermind 25955 points
    Hi Hedley,

    The EV2300/EV2400 will allow you to communicate to the gauge with a Windows based PC using bqStudio.

    In your final product, a microcontroller/host processor may be utilized to talk to the gauge via I2C. The EV2300/EV2400 is used for development and configuration of the gauge with your batteries. The EVM and EV2300/EV2400 are not intended for use in your final product.

    Other USB -> I2C interfaces may be used, but this is not recommended for development. The EV2300/EV2400 + bqStudio provides a graphical user interface for device programming and logging.

    bqStudio may be downloaded here: www.ti.com/.../bqstudio
    The EV2400 may be found here: http://www.ti.com/tool/EV2400
    The BQ34110EVM-796 includes a user guide that describes the use of both bqStudio and the EV2400 with the bq34110EVM found here: http://www.ti.com/lit/sluubi

    These tools will enable you and your engineers to configure and optimize the gauge for your application. Once your gauge is configured and optimized, a golden image may be created with these tools. That golden image may then be used to flash your gauges in production.

    Sincerely,
    Bryan Kahler
  • 0 in reply to Bryan Kahler
    Prodigy 50 points

    Thanks for comprehensive reply and confirming that the toochain is primarily to get the golden image to load into  target devices in production . We will roll our own as Mouser places these little PCBs into a large box so the shipping is $ 65 per board and the boards are also overpriced . Whilst a small input cost all other vendors over the last 30 years price the  dev boards agressively with the goal of selling chips . TI seem to do the opposite. I don’t know if it is because the battery chargers and gauges are low volume or old parts .

    In our use case the product with charger and gauge is clipped on / retrofitted to existing batteries in the field so is thier any point in profiling the golden image at the factory when we just need a default for a “ typical “ SLA or lithium ion.

    ??.

  • 0 in reply to hedley davidson
    TI__Mastermind 25955 points

    Hi Hedley,

    EVMs from TI are intended to allow a customer to evaluate the particular device. The EVMs are not intended as a 'breakout board' to be placed in a product, but instead as a testbed for the customer to evaluate the part over a range of configurations.

    This approach can be readily seen with the bq34110EVM-796 as the EVM supports up to 5 V single cell and 16, 32 and 48 V multi-cell configurations.

    Although TI does support legacy parts (that are not recommended for new designs), the BQ34110 does not fall into the legacy category.

    For multi-chemistry system side or pack side strap-on-gauges, the BQ34110 and BQ34z100-G1 are recommended for new designs.

    All batteries are different - the correct chemID or CEDV parameters will need to be utilized with the existing batteries, and an optimization cycle and learning cycle run to ensure the most accuracy when gauging, especially when connecting to old batteries that no longer match their rated capacities.

    Sincerely,
    Bryan Kahler

  • 0 in reply to Bryan Kahler
    Prodigy 50 points

    Thanks Bryan 

    If I understand correctly - Our Add on module containing the TI charger ( BQ 24450 ) and the Guage ( BQ 34110 ) with back end micro and comms could not be plugged onto an existing battery in the field as an optimization cycle and learning cycle would have to be run first so that each module is " matched " to a specific SLA battery . If correct ,  this would mean on battery replacement the optimization and learning cycle would have to be repeated which is a lengthy process in the field . 

    We have thousands of installed battery backup units which support " critical" systems where we guarantee the end user 99.9% system availability so were designing a module to " plug onto " existing batteries so that they had real-time and SNMP traps indicating battery status and or need to swap out. 

    If my understanding of your response is correct the parts above will not do the job , so  can you suggest alternate parts for our use case eg impedance tracking . 

    Basic requirement - a plug on charging and gauge that can be affixed to any battery in the field and provide feedback to a control room . If battery must be replaced the swap out time in the filed must be under 1 minute. 

  • 0 in reply to hedley davidson
    TI__Mastermind 25955 points
    Hi Hedley,

    If starting with brand new cells in the factory, a 'golden image' may be used. The board may be 'calibrated' in the factory. Starting out, when properly programmed, the gauge will know what a brand new healthy cell will look like.

    Running the learning cycle will update the impedance values of the battery with respect to the depth of discharge of the gauge.

    For the most accuracy, this would be done as an intentional charge/discharge step in the factory either individually or as part of the 'golden image'

    Without a priori and a posteriori knowledge, there is no way for any gauge, by any manufacturer, to fully characterize the parameters of an unknown cell at an unknown state.

    However, the gauges are constantly learning, and may also update naturally over the charge/discharge of the battery. Depending on the field procedures and device design, with a SNMP trap, this data may be reported back to home base after a quick installation in the field.

    Section 2.11 End-of-Service-Determination in the TRM ( http://www.ti.com/lit/sluubf7 ) may be of interest for your application.

    Sincerely,
    Bryan Kahler
  • 0 in reply to Bryan Kahler
    Prodigy 50 points
    Thanks again .

    Our devices are installed at many international airports , where they provide backup power to electronic access control . Failure to open a door can mean > 300 pacs cant board a plane so the impact is large . Currently the SLA ( 12VDC 7AH ) are trickle charged but we have no idea of the state of health until there is a power interruption and the wheels fall off in grand style. The load draws ~ 1.8 Amps. The primary power is reasonably reliable but each time there is an incident the client wants to know why " just when they are needed the batteries are flat ? "

    Basically as we are not scratching for uA of current and very high accuracy I thought we could calibrate the board at the factory on a typical new battery . Once installed on an in service battery the charger would make best attempts to charge to full state and the gauge would then have a starting point which we could use to " offset " the factory parameters.


    Regards\