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BQ24610EVM: Suggestion regarding selecting a charger Module EVM

Part Number: BQ24610EVM
Other Parts Discussed in Thread: BQ34Z100, BQ24610, BQ25713, EV2400, BQ25713EVM-017, BQ25713B

Hi,

We are conducting academic research related to electric drivetrains and want to be able to charge Li-ion battery packs using a small DC generator of sorts. The DC output from it would need to be fed into a charger first, to charge the Li-ions correctly.

  • We are considering buying one of your charger EVMs (such as BQ24610EVM) considering multi-cell capability and high ranges of voltage input/output seem appropriate.

  • However I am unable to find (apart from the std. user guide) any reference on how to make these connections to actually charge the batteries for evaluation and powering our Load parallely. 

  • The user guide says says something about changing some 'R25 or R28' values. Does this mean physically adding/removing resistors on the PCB or is it a jumper setting? We are looking to eventually evaluate different packs (1S, 2S, 3S and 4S); so it is a bit unclear if the same module (which is a multi-cell charger) is able to help us do the evaluation of all our Li-ion packs.

  • We are using the BQ34z100 EVM as our fuel-gauge to log data such as SOC, voltage etc. And the charger is supposed to go across the (BAT+,PACK-).

Are there any other appropriate suggestions of a product we could purchase instead?

Best,

Shrey KALRA
(Research Engineer)
NTU - Singapore

  • Hi Shrey,

     BQ24610 has direct powerpath, so load can be connected at SYS node, and will be powered by adaptor when adaptor is present, or by battery when adapter is absent.

    The charge regulation voltage is set through resistors which form a resistor divider with the midpoint tied to VFB (section 9.3.1 Battery Voltage Regulation of the datasheet). From the schematic on the user guide, R25 and R28 are these resistors. On the EVM there is no jumper configuration to set charge regulation voltage, and will have to be soldered/de-soldered. BQ24610 can support 1S-6S configuration so it should satisfy all your requirements.

    For BQ34z100 EVM you will have to create a separate post with that part number in the title, and the expert supporting those parts will be able to answer your question.

    Which features in BQ24610 are lacking for your system considerations, and based off of that I can recommend other charger products if need be.

  • Hi Kedar,

    Thanks for the helpful response. So we can in fact, utilize the BQ24610 for all battery packs (from 1S-6S) but for each test we must replace resistances and modify the board; Right?

    1. Going by specifications the BQ24610 seemed fit, but can we find any other module/EVM that has similar multi-cell capabilities BUT does not require soldering/de-soldering every time? That is something we would rather like, for ease of conducting tests.

    2. Considering the voltage regulation, would it be fine to feed-in direct DC (say 8-15V) to the charger from a small DC generator source (instead of an adapter)?

    3. Also part of our study is to be able to configure the power path itself in different modes (such as: (a) load powered by battery alone, (b) load powered by secondary source while the battery gets charged, (c) load powered by both battery+secondary source etc.). There may not be an exact module that does all of these things, but we hope to find a combination of modules that fit together are able to do so.

    This should convey a clearer idea of our requirements, hopefully you can make some suggestions in this regard. Thanks again.

    Best,

    Shrey KALRA

  • Hello. Any follow up?

    Best Regards,

    Shrey KALRA

  • Hi Shrey,

    1.     You can look at using the BQ25713, however you would need a host to configure all the registers, and it doesn't go up to 6S. With regards to the host, if it is just for evaluation/feasibility study you can use the EV2400 with the .bqz file.
    2. This part is a buck charger, and buck battery charers have limitation of not operating at 100% duty cycle, so they require an input voltage higher than output voltage. With your 8V-15V supply you will not be able to charge for 4S/5S/6S.
    3. This part has direct powerpath however it does not have supplement mode.
      • a) can be achieved just by removing the input adaptor, and then battery will supply system through the PFET driven by BATDRV
      • b) The SYS has a direct connection to the adapter, so as long as input current limit is not hit, then the adapter can supply both SYS load as well as charge current
      • Not possible, as ACDRV and BATDRV operate complementary to each other.

  • Hi Kedar,

    Yes it is a feasibility study at this point. Appreciate your suggestions regarding our setup and pointing to the BQ25713.

    1. We already do have an EV2400, which can be used to configure the device registers I suppose. We also have a separate host (micro-controller) for I2C communications/ read-data after configuring. So do you think the BQ25713EVM-017 module would suit us then ? ( it is up to 4S but that is fine ). Once fully configured, we can unplug the EV2400 and let the device work on its own independently?

    2.  Do BQ25713 and BQ25713b have any difference? 

    3. As you elaborate in Your 3rd point for the BQ24610, is the same power path logic also applicable to the BQ25713 as well ?

    4. Could you please explain what you mean by (.bqz) file and what is it exactly?

    Thanks for your helpful responses !

    Best regards,

    Shrey KALRA

  • Hi Shrey,

    1.   The issue with the BQ25713 working independently is that it is intended to run with constant host support. This part does not handle termination, and this is to be taken care of by the host or the gauge in the system. Moreover any POR would result in the registers being reset to their default settings, which by default is to have 0A charge current and the CELL_BATPRESZ resistor setting. The BQ25713 is probably overkill for your application, but if it is for ease of use, then this part would be better (if you are ok with up to 4S) as long as you keep the host (EV2400 with .bqz file) connected so you can monitor. This allows you to change the charge regulation voltage through I2C for your multiple configurations
    2. The I2C address is different, so customers who have other devices in their overall system with same I2C address as the charger have option to choose between these 2 I2C addresses.
    3. BQ25713 has added benefit of supplement mode: Battery Supplements System When Adapter is Fully-Loaded
    4. You use the .bqz file that TI uploads as part of the BatterManagementStudio GUI, which allows you to easily configure different bits in the registers without the need to write your own full host control code. Allows for easy evaluation of the part, which for your feasibility study will probably be helpful. Available for free download here: https://www.ti.com/tool/BQSTUDIO

  • Hi Kedar,

    Your responses are quite helpful to our case, thanks for your time:

    1. Seems like the BQ25713 is not independent at all. Well, we eventually want to remove the EV2400 and use our own host (such as a PXI or similar DAQ) to run the system. As you said, is there a way for the BQ25713 registers to be "taken care of by the host or the gauge in the system" since we already have our gauge (the BQ34Z100 evm) or ONLY our EV2400 can be used as a host and MUST always be hooked up in the loop along with the PC? What are our options in this regard?

    2. If you think BQ25713 would be " an overkill " would you be able to suggest another module/EVM for us that can be much more suitable to our application? Since by now you have a much clear understanding of what our team is trying to do. If not then we may have to go with the BQ25713EVM for the meantime.

    Best regards,

    Shrey

  • Hi Shrey,

       1. BQ25713 is not intended to be independent as it is an extremely feature rich part. I don't understand the rest of your question? The termination is to be taken care of by gauge or host. I think there is some misconception here.

       2. With regards to your application, I understand it is a "feasibility study" and the aim behind it, however I am not sure if you are trying to evaluate different battery cell count to narrow down which one you want to use, or if you need the charger to handle multiple cell counts on the fly even after your study is done. If you have 4 or 5 different battery cell counts you want to test, and then you narrow down to 1 specific cell count, I would recommend BQ24610 for ease of use. If you wish to have a final product with flexibility to charge different cell counts, then I would continue with BQ25713.

    With respect to it being overkill, there are still elements of your system I don't know. However as this is a buck boost charger, with this charger you can use your 8V-15V generator source as input to BQ25713 and then test all cell counts from 1S to 4S.

  • By recommending BQ24610 for the specific use case, it would be easier to get it set up and running. So if you need only one cell count in the final application, I would recommend to solder/desolder the resistors used to set charge regulation voltage and proceed with testing using BQ24610.