Battery discharge/charge application question

Hi @mliberty,

I would like to monitor the battery charge/discharge performance for my PCB and wanted to double check if this is something I can do with JS? The reason for asking is that it will require bi-directional current, to monitor both when the battery is charging and also when the battery is powering the device. Obviously, not at the same time :wink:

Hi @SidPrice,

The JS110 is primarily intended as a 1 quadrant device (+current, +voltage), but it does measure into the -voltage and -current ranges for some 4-quadrant capabilities. The fast current autoranging only works with +current. However, it does autorange slower on negative currents, and battery charging does not normally have fast transients. You have a few options:

  1. Use Joulescope as normal with your target device. The negative current maximum design threshold is -1.8A, so as long as your negative current does not exceed -1.5A or so, Joulescope will easily measure it. Do note that the autoranging on negative currents is much slower.
  2. Use Joulescope to measure discharge into your target device, and reconfigure your setup for charing. To measure charging, connect your “target” device to Joulescope’s IN and the battery to Joulescope’s OUT.
  3. Tell me that I should start developing a full 4-quadrant Joulescope immediately.

Check out this reply which contains information on Joulescope’s designed ranges. Note that 0.5.0 fixed the negative current autoranging oscillation.

1 Like

@mliberty … well of course #3 :wink:

Seriously either #1 or #2 would work I think. I can set up to monitor the charge and discharge tests separately, not an issue. My concern was possibly doing damage to the JS at the “turn-around” points, e.g when discharge changes to charge. Currents for charge are max of around 500mA.

Thanks, Sid

1 Like