Tristar mppt 60 charging current

sdad46

The amount of current that the controller sources can be very different from what is being delivered to the battery for charging, depending on load draw.  Other manufacturers implement a shunt sensing circuit to see how current is actually getting absorbed by the battery. How does morningstar deal with this issue? 

mike95490

I expect they measure Voltage drop across one of the output elements.

Photowhit

Until recent charge controllers by Midnite and Schnieder, charge controllers used their internal shunt and the batteries own nature in limiting the amount of current it will absorb to monitor charging. Charge controller can still sense when the voltage is 'running away' which it does at 80-85% full, and then it changes from a bulk to an absorb cycle and usually they either time them with a standard often 1-2 hours (which can be much too short) or as a percent of the time it took in Bulk. Most charge controllers still work this way. 

I think more advanced charge controllers will also drop back into Bulk if a load is present for a long enough time to drop the voltage below a set point, I think system voltage is used. They can also reset the timer for absorb... Some you can also set the amount of time you want the charge controller to be in absorb, and even end amps at the charge controller.