As he said, the dicharge rate is not controllable, and it too uses a POT.

Any charger that uses a "DIAL" or knob to control the charge rate, uses a POT and is prone to innaccuracies.

I'm NOT telling you that you cannot use these, however because you are looking for your new "main workhorse" charger, investing in one with finer controls and capabilities is a good idea.... e.g. a computer controlled one.

A quick field charger is called a "Field" charger for a reason.

If you can opt for one that will do more to start with, so you will not need to later purchase a more capable device, when you could have been using one all along.