• Looking for turn-key BMS system

    From Klaus Vestergaard Kragelund@21:1/5 to All on Wed Oct 2 15:12:22 2024
    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh battery modules, which each has a BMS controller, that monitors and balances 12
    lithium ion cells (4 series connection of 3 parallel cells). Each of the modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low volume.

    I am looking for a supplier of finished batteries with BMS and also BMS controller. Perhaps one of you guys has worked with this? (need a stable supplier)

    Client is based in the EU.

    Thanks

    Klaus

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  • From john larkin@21:1/5 to klauskvik@hotmail.com on Wed Oct 2 07:58:43 2024
    On Wed, 2 Oct 2024 15:12:22 +0200, Klaus Vestergaard Kragelund <klauskvik@hotmail.com> wrote:

    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh battery >modules, which each has a BMS controller, that monitors and balances 12 >lithium ion cells (4 series connection of 3 parallel cells). Each of the >modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low volume.

    I am looking for a supplier of finished batteries with BMS and also BMS >controller. Perhaps one of you guys has worked with this? (need a stable >supplier)

    Client is based in the EU.

    Thanks

    Klaus

    I have a list of future projects which includes a battery monitor. I
    figure it might have a wire per cell (+1 at the end of the string) and
    snoop voltage, ripple, and estimate cell impedance, something like
    that. Measuring string current would help.

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  • From Bill Sloman@21:1/5 to john larkin on Thu Oct 3 03:20:49 2024
    On 3/10/2024 12:58 am, john larkin wrote:
    On Wed, 2 Oct 2024 15:12:22 +0200, Klaus Vestergaard Kragelund <klauskvik@hotmail.com> wrote:

    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh battery
    modules, which each has a BMS controller, that monitors and balances 12
    lithium ion cells (4 series connection of 3 parallel cells). Each of the
    modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low volume. >>
    I am looking for a supplier of finished batteries with BMS and also BMS
    controller. Perhaps one of you guys has worked with this? (need a stable
    supplier)

    Client is based in the EU.

    Thanks

    Klaus

    I have a list of future projects which includes a battery monitor. I
    figure it might have a wire per cell (+1 at the end of the string) and
    snoop voltage, ripple, and estimate cell impedance, something like
    that. Measuring string current would help.

    Measuring the core battery temperature is a good idea. Measuring surface temperature of the battery is useful additional information.

    Battery output voltage depends on temperature and the state of charge
    (not to mention the current flowing through the internal resistance).

    It you have enough current flowing through the battery to create thermal gradients, life can get complicated and you'd need to do a bit of
    thermal modelling on the fly.

    I got asked that question at a job interview - I didn't get the job.
    Maybe the interviewer thought that I was over-complicating the task.

    --
    Bill Sloman, Sydney

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  • From Lasse Langwadt@21:1/5 to Klaus Vestergaard Kragelund on Thu Oct 3 00:31:25 2024
    On 10/2/24 15:12, Klaus Vestergaard Kragelund wrote:
    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh battery modules, which each has a BMS controller, that monitors and balances 12 lithium ion cells (4 series connection of 3 parallel cells). Each of the modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low
    volume.

    I am looking for a supplier of finished batteries with BMS and also BMS controller. Perhaps one of you guys has worked with this? (need a stable supplier)

    Client is based in the EU.

    Thanks

    Klaus

    https://www.victron.dk/ ?

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  • From Klaus Vestergaard Kragelund@21:1/5 to Lasse Langwadt on Thu Oct 3 11:17:28 2024
    On 03-10-2024 00:31, Lasse Langwadt wrote:
    On 10/2/24 15:12, Klaus Vestergaard Kragelund wrote:
    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh
    battery modules, which each has a BMS controller, that monitors and
    balances 12 lithium ion cells (4 series connection of 3 parallel
    cells). Each of the modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low
    volume.

    I am looking for a supplier of finished batteries with BMS and also
    BMS controller. Perhaps one of you guys has worked with this? (need a
    stable supplier)

    Client is based in the EU.

    Thanks

    Klaus

    https://www.victron.dk/ ?

    Looks good, they have a lithium battery with internal BMS at resonable
    price.

    No State of Charge (SoC) though for the battery. Is it possible to get
    rough SoC from a lithium battery by voltage sensing only?

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  • From Klaus Vestergaard Kragelund@21:1/5 to Klaus Vestergaard Kragelund on Thu Oct 3 12:32:01 2024
    On 03-10-2024 11:17, Klaus Vestergaard Kragelund wrote:
    On 03-10-2024 00:31, Lasse Langwadt wrote:
    On 10/2/24 15:12, Klaus Vestergaard Kragelund wrote:
    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh
    battery modules, which each has a BMS controller, that monitors and
    balances 12 lithium ion cells (4 series connection of 3 parallel
    cells). Each of the modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low
    volume.

    I am looking for a supplier of finished batteries with BMS and also
    BMS controller. Perhaps one of you guys has worked with this? (need a
    stable supplier)

    Client is based in the EU.

    Thanks

    Klaus

    https://www.victron.dk/ ?

    Looks good, they have a lithium battery with internal BMS at resonable
    price.

    No State of Charge (SoC) though for the battery. Is it possible to get
    rough SoC from a lithium battery by voltage sensing only?

    A number of hits online says that SoC is difficult to determine for a
    Lithium battery purely from the voltage.

    But for the cell I am using, the datasheet seems to disagree (if
    compensated for temperature)

    https://electronicsdesign.dk/tmp/ur18650.pdf

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  • From Theo@21:1/5 to Klaus Vestergaard Kragelund on Fri Oct 4 12:04:25 2024
    Klaus Vestergaard Kragelund <klauskvik@hotmail.com> wrote:
    Hi

    One of my clients is looking for replacing existing HW, 2 200Wh battery modules, which each has a BMS controller, that monitors and balances 12 lithium ion cells (4 series connection of 3 parallel cells). Each of the modules has SOC output in the form of LEDs.

    Beyond that, the overall system has a BMS controller that is powered
    from either 24VDC (grid connected) or from the batteries. This BMS
    controller also has SOC, with a connected display.

    The client would like a turn-key solution, so minimal NRE due to low volume.

    I am looking for a supplier of finished batteries with BMS and also BMS controller. Perhaps one of you guys has worked with this? (need a stable supplier)

    Client is based in the EU.

    Victron has been suggested, who are a good start for turnkey options.

    In the DIY home storage and EV (electric bike, car) community there are a
    bunch of 'smart' Chinese BMSes in use: (in roughly descending order of usefulness)

    JK BMS (Jikong)
    JBD BMS (Jiabaida)
    Daly BMS

    which operate via Bluetooth, having their own phone apps but also a protocol via RS485. They come in versions from about 20A to 300A (although I
    wouldn't run one near its maximum rating).

    Then there are vendors who make rack-mount LiFePO4 batteries with BMSes designed to talk to solar inverters:

    Pylontech
    Seplos

    Usually those rack batteries are in 2+kWh configurations so perhaps less
    useful to you, but maybe the BMSes are.


    Probably not the kind of supplier or level of integration you want to deal with, but it's useful to be aware of the communities using them. More info
    on various forums, eg: https://diysolarforum.com/forums/bms-battery-managment-systems.23/

    Fogstar as mentioned are just resellers of the Pylontech and other
    batteries.

    Slightly more integrated-ly, there are LiFePO4 'leisure' batteries that have the BMS included. Some of those offer a display or bluetooth app that might give you enough information.

    Theo

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