Todays's tronix project, LM2596 switcher as a current source.
For the big battery loader would it not be nice to have a current source that was simple, and made from stuff I already have in the box.
The big ebay modules are cheap, but a bit of overkill.
Had once (upon a time) made a little test board for the LM2596-3.3V version, that I actually use for any other volts >= 3,3 with the aid of an extra resistor, so, while plopping down on paper some circuits for the battery whatsit balancing act? anyways, why not muddify that LM standard circuit a bit.
This is what such a circuit looks like... 3.3V (or more) and a few amps, no heat.
Muddified it looks like this:
That is an extra PNP and an extra NPN, normally (say power on) pin 4 is low, (the feedback pin), and the LM starts outputting all it can. In the output shunt Rs , at least when some load is present, will drop some voltage. Say Rs is 1 Ohm, then the NPN will start conducting at about .7 V or 700 mA. This will cause the PNP to conduct too, and the LM adjust pin is pulled high, and it relaxes and goes watch TeeFee while the current remains at say that 1 A.
None of the resisters are critical [1], the base resistor in the NPN is just to reduce possible peak currents (will those ever happen), the 47 k is probably not needed either in normal temperatures where human life forms dwell, and the other sister is (gets out of chair and measures it) 1.6 k (1600 uncles). that is the 2 in series, so total, OK. Hope this helps, else use SOS.
[1] Just grabbed in the used parts box and use whatever came up, give or take a few grabs This is to support my statement that a good designer makes circuit that also work with 20% components.So the circuit if guaranteed free from opti-mice.
PS not sure the circuit diagram is right, I soldered the circuit first, the pictures rule.
Oh well.