Found out why my tests were being ruined at the end of discharges:
- the KP184 manual is incorrect/incomplete, and possible firmware bug
- using other programs in between Test Controller sessions that control the KP184 differently
- not knowing there's a difference between the way Test Controller and other programs operate the load
The KP184 manual describes the above as a setting which will turn off the load if the input voltage of the load is lower than the set voltage.
This kind of happens. But what happens first is that milliseconds before that value is reached, the load throttles the current down so it doesn't reach that voltage until it can abuse the cell/pack for a bit. I think it's for testing power supplies and giving it some leeway before it kicks off. If you're testing batteries, you might want this off, entirely. But you definitely want it below your cutoff if you're testing capacity.
How the aforementioned setting got set and stayed set, in my case, was playing around with other programs that change settings differently than Test Controller. When you set the load current in Test Controller, that setting is sent to the load before the test begins, or if you click CC in the setup popup. The cutoff voltage is never sent to the load, Test controller merely sends an "off" signal when the cutoff voltage is detected. When I opened another program while experiencing new-user shock with Test Controller, I spotted the threshold voltage and set it. This "permanently" set that setting as if I were using the panel of the KP184. I used that program again and changed that setting again to a higher voltage in order to escape that low voltage cutoff/throttle issue. But as we now know, if
load threshold is as high or higher than
end voltage(whether set in Test Controller or the front panel itself), current throttling will occur before actual cutoff happens, even if the load is set to BAT mode. Threshold voltage is more of a power supply testing mode which in my opinion should not be in effect while in BAT mode. But that's an issue for another thread.
So maybe a future version of Test Controller would set the voltage threshold to a 0V setting if it can detect it being higher than the selected minimum voltage. Now that I know about it, I don't think it's going to be a problem for me.