Post Go back to editing

LTC4079 input resistor

Hey everyone,

I have a power source providing a primary load with a lot of power, so like 300W(solar panel), the panel operates at 40V, from this source I'd like to pull a bit of power to charge a set of batteries.

The battery pack's charged voltage will be 16.4 volts, so the drop over the LTC4079 will be big ! This will definitely push the temp of the device and I don't wan that. to avoid this, I want to place a series resistor(as recommended by the datasheet)

To spec the resistor, I'd like to know what the input current to the device is so I can determine the resistors required power dissipation? I might be missing it from the datasheet.

I wanted to use this energy harvester as the panel will be at MPPT and if a considerable amount of current is drawn it wouldn't be good for the panel.

Thanks in advance for any help!

  • Hello,

    The input current is not a constant value, which is why it can't be specified in the datasheet. For a linear charger, the input current will be equal to the output current. So, if you want to reduce power dissipation, all you need to do is reduce the battery charge current.

    If you're concerned with heating and power loss, why not using a switching battery charger instead of a linear one?