back to constructing my own

3 adjustable current draw:


I'm in the process of ordering several components to upgrade my current test jig. This includes a "current
shunt monitor" IC that can be placed across a shunt on the high side of the load (at any voltage) and will
also siphon power off that to run the chip. It produces a fixed 20x voltage gain on the shunt, which I should
be able to feed into an op amp network that combines with a selectable voltage from a control knob to drive
the gate on the mosfet(s) to achieve the selected current.

This should also have the benefit of making the control knob linear with respect to load current. (I found
that mosfet current does not rise linearly with increases to gate voltage)

I had another inspiration today. I had been trying to develop a way to divert power going to a battery from a
solar controller. The idea was to sample the power going back from the controller to the battery, and use that
to adjust the load. The problem that presents is it doesn't create any "differential" that can be adjusted with
feedback. My new idea is to add a second current detector going to the load. This would allow me to compare
power coming from the controller with power going to the load, and create a feedback signal (to the mosfets) to
equalize those two currents. It will probably be necessary to have some small fixed load ahead of the mosfets,
to insure there is always a small amont of current drawn even when the solar controller isn't proving power, to
make the mosfets default to fully off.



2025.06.02 solar load ideas:



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