Morningstar MPPT grounding problem

I attached my wiring diagram

Here's the original story. I have a Morningstar MPPT-45. I did not have the system grounded, but the system worked great for a while until I tried hooking up my Battery Sense wire to my charge controller. The positive lead touched the case and started frying the board of the controller (it produced a nice buring smell). The two welds where I plug in the TS-M2 digital metering device are scorched, but the metering panel still works fine. SO after this incident, I bought a Midnite Solar 63amp GFP (the little green square on my diagram, the squares with "##A" on them are breakers) and wired it to the directions. But am still am having problems. I don't know if I need to send the controller in to get the board fixed, or if I wired it wrong.

I am having three problems right now.
1. The charge controller continuosly restarts. I disconnect the battery sense wires, but it is still doing the same thing

2. When I was testing the controller over the weekend I was recieving the "Overcurrent" fault even though I only had one panel of about 8 amps feeding the controller.

3. When I turn on my modified inverter with the GFP in the "ON" position, the GFP buzzes.

If more info is needed, let me know!



  • BB.
    BB. Super Moderators, Administrators Posts: 33,491 admin
    Re: Morningstar MPPT grounding problem

    Question about the MSW inverter---Did you parallel the AC output with the TSW inverter?

    Is the MSW inverter AC output "floating" (grounding the "neutral" and grounding the battery bank can let out the magic smoke on many MSW inverters).

    You should also check the manual on the TSW inverter--Many can support a Grounded Neutral system--But there may be some that cannot.

    Grounding the battery bank and grounded MSW inverter AC output could be a change that is causing problems.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Morningstar MPPT grounding problem

    I think, that most of the time, when the magic smoke comes out of the circuit board, things are generally broken, till the wizards at the factory, fill the charge controller with new magic smoke.

    And it sounds like there are 2 problems - the other, BB addresed about the grounding.
    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 ||
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