Constant current source?


I’d like to use my Otii as a constant current source. In particular, I want to write a simple script to charge a capacitor/battery at a constant current until it reaches some max voltage setpoint.

I thought I could do this by modifying one of the constant current discharge scripts, essentially setting the power regulation mode to “current” and giving the device a positive (rather than negative) current setpoint. The outcome of my simple attempt is zero current.

Can anyone suggest what I might be doing wrong here?


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Hello Jay

Unfortunately the current regulation mode only handles negative currents at this point, i.e. discharging a battery. It’s however something we desire to improve in an upcoming firmware.

You might be able to write your own simple current regulation by looping in your script, reading current and adjusting voltage. It will of course not be as fast as the one native to the firmware though. Might work, might not, depending on battery chemistry.

If you are interested in beta-testing current regulation for positive currents please create a case and we’ll attach a new firmware there as soon as it’s ready for evaluation.

Thanks Christer,

I suspected that might be the case. I will try looping and adjusting the voltage setpoint.


I’m interested into that feature as well! Is there any news?

This functionality will be included in an upcoming firmware release, we’re looking into whether to make current limiting the new default in voltage source mode instead of the cutoff used today. Current limiting would make the voltage source mode behave like a CV/CC output which suit the use-case mentioned above. Test firmware is available now.

I’d like a copy of the test firmware please.