Can the LTC2941 or LTC2942 be used with a 3-Cell Series NiCD?

Hello.

I'm looking at using the LTC2941 (or 2942) for use as a gas gauge for a 3-Cell In Series NiCD Pack for general gas gauging. The datasheet mentions it's designed for Li-Ion but the operating voltage checks out (even under my charger, a PowerStream PST-3P10-N0508 which is 1.6V/cell and peaks at 5.25V).

I'm still relatively new to the fuel gauge space, but I'd imagine there's no chemistry limitations here since this is a fuel gauge and not a charger IC. So I suppose I'm looking for any underlying asterisk so I don't get burned.

Any advice is appreciated.

Thanks.

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  • 0
    •  Analog Employees 
    on Apr 26, 2018 9:30 PM

    Hi,

       The LTC2941 does work with battery types other than Li-ion, as long as the terminal voltage stays between 2.7V and 5.5V, including charging voltage. You have to have enough juice to power the device, but not enough to damage it. If the Vsense+ voltage dips below the UVLO threshold (< 2.7V) then the device will enter reset, but with a stack of 3 NiCd cells (1.2V x 3) you should be reasonably far from that under most conditions. You can read the status register to determine if the device has entered UVLO at any point.

    The coulomb counter is fairly generic, and just integrates current flowing in the sense resistor, regardless of battery chemistry.

    Thanks!

Reply
  • 0
    •  Analog Employees 
    on Apr 26, 2018 9:30 PM

    Hi,

       The LTC2941 does work with battery types other than Li-ion, as long as the terminal voltage stays between 2.7V and 5.5V, including charging voltage. You have to have enough juice to power the device, but not enough to damage it. If the Vsense+ voltage dips below the UVLO threshold (< 2.7V) then the device will enter reset, but with a stack of 3 NiCd cells (1.2V x 3) you should be reasonably far from that under most conditions. You can read the status register to determine if the device has entered UVLO at any point.

    The coulomb counter is fairly generic, and just integrates current flowing in the sense resistor, regardless of battery chemistry.

    Thanks!

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