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Push Button Fuel Gauge for 12.8V LFP 4 Cell Battery Pack

Other Parts Discussed in Thread: BQ20Z65

HI, I am needing a simple Push Button Fuel Gauge for a 12.8V 4 cell Lithium Iron Phosphate Battery Pack.

What are my options? I would love to just have a board that you can connect to the + & - of the battery and then you can simply push the button see the battery capacity.

What are my options?

I am designing portable solar power systems and I am interested in building systems with data displays like shown here http://www.batteryspace.com/Touch-Screen-Color-LCD-Monitor-for-Smart-Battery-Systems-SBS.aspx but am not really sure if there other options out there for us to work with other than the Victron Battery Monitors. 

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  • Hello

    we have a number of device that you can use to develop a board with push button state of charge display.

    have a first look at bq20z65.

     

     

  • Thanks for the reply.

    I am not a electrical engineer, so what type of person or company should I look toward to help me build a board with the LED's and Push Button that I can use in my product? I have no idea where to even begin looking so any help is great.

  • Is there a engineer that I could talk with over the phone to get a better idea of what exactly I need to accomplish my goals?

    If so please let me know who I should be talking with, I read through all the documentation and have a good understanding but want to talk with somebody who knows you products better than I so I can be 100% sure what I need.

  • Ryan,

    The example system that you linked to is designed to talk to a "smart" battery pack that has a fuel gauge inside already.  It basically reads the standard SBS commands from the gauge in a battery pack and displays all the information on the LCD screen.

    The first question is whether the LiFePO4 pack that you are wanting to interface with already has a fuel gauge inside or not.  If it does then you could use the system you linked to or ask that company or a similar one to create a simpler version that just had LEDs.  Or you could ask any developer who can program microcontrollers to make a simple board with a microcontroller, a pushbutton, and LEDs that will talk to your smart battery pack using SMBus (like I2C).

    If you have bare LiFePO4 cells with no electronics on it then you really need a fuel gauge.  The same company you linked to also has such a board already made: http://www.batteryspace.com/Smart-Battery-Systems-SBS-with-SmBus-V1.1-support-for-12.8V-LiFePO4-batte.aspx

    It already has LEDs on it, too.

    Or, as BatteryBorne suggests, you can make your own board from scratch using a newer gas gauge from TI like the bq20z65.

    If this doesn't make sense, please just post with the answer to this:

    Does your pack have a fuel gauge inside already or not?

    If you have a link to your pack it might help us understand what you are trying to work with.

  • Thanks for the reply!

    The PCM with Smartbus and LED Fuel Gauge built in is not currently available and and more importantly maxes out at 7 amps. We need 15 Amps minimum. 

    We are using this 16A PCM with Cell Balancing. http://www.batteryspace.com/pcmprotectioncircuitmodulefor4cells128vlifepo4batterypackat16alimited.aspx

    There is no SmBus on this board. All I need is a simple push button fuel gauge based off Voltage I guess.

    I can not find any PCMs with SmBus built in that is able to handle over 7 Amps, we need 15 Amps Minimum.

    Thanks for the help.

     

     

     

  • Hi Ryan,

    I suppose you can either ask that company to customize their product for your application, or you might be able to modify it (change the sense resistor and dataflash configuration) yourself, or else design your own from the ground up.  I'm sorry I can't point you to one off the shelf that works for you.