Tristar mppt 60 charging current

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
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    I expect they measure Voltage drop across one of the output elements.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • Photowhit
    Photowhit Solar Expert Posts: 6,004 ✭✭✭✭✭
    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.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former, 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.