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DC930A unexpected behaviour

Morning!

I am looking to integrate the LTC4001 into a new product and am seeing some unexpected behaviour on the DC930A eval board.

When I try and charge a battery that has been deeply discharged (terminal voltage < 3V), I find that the charger trickle-charges the battery up until a terminal voltage of ~3V, then stops and raises a fault condition. Is this expected behaviour from the LTC4001?

Also, when I try to charge a 5.5mAh battery that has been discharged, I find charging continues for ~5hrs, until the battery is almost, but not completely charged (charge voltage = 4.2V, charge current = ~350mA). I would have expected charging to terminate after ~1.3hrs as the DC930A has a 100nF cap on its timer. Any ideas why the timer does not go off after 1.3hrs?

Any help you can provide would be greatly appreciated.

All the best

Dan

  •  Hello,

    What size is the deeply discharged battery and how long did it take until it reported the failure?

    A 5.5mAh battery is really small. What is the ESR? What was the JP1, JP3, and JP4 settings?

    Is there an ammerter between the battery and the demo board?

    Is there anything on the TIMER turret like a scope probe or multimeter?

    What is happening with the C/10, /CHRG, or /Fault pins during these effents?

    What does the PROG pin voltage when the timer is running for 5 hours?