MPPSOLAR MPPT BOARD defect

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bergloewe82
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MPPSOLAR MPPT BOARD defect

Post by bergloewe82 »

Hello Community,

Since May 2020 Im running a MPPSOLAR PIP 2424MSD DUAL MPPT Inverter.

In the last week the MPPT Board get problems. They start charging the battery in the morning normally. After they reach about 7A Charging Current they disconnect the PV Array from the MPPT Controller. In this Moment the Voltage increases to 72V and everything else is working. AC-Output, Battery Discharging...

When i restart the inverter the game starts again like described. When I restart the inverter with less sun, he will work for hours, till he reachs the 7A again.

MPPSOLAR support says that the MPPT BOard is defect.

Has anyone a recommendation for me how to find the error!?
PV Array is checked and works fine on another Inverter.

BR and THX for your help
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coulomb
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Re: MPPSOLAR MPPT BOARD defect

Post by coulomb »

bergloewe82 wrote: Mon, 05 Apr 2021, 00:13 In the last week the MPPT Board get problems. They start charging the battery in the morning normally. After they reach about 7A Charging Current they disconnect the PV Array from the MPPT Controller.
Have you checked the temperature of the SCC board? Just reading the reported "inverter" temperature using Watchpower etc should be fine. But 7A battery current isn't much, so real over-temperature seems unlikely.

Do the dual MPPT models literally have two SCC boards? Or one board with two channels jammed onto it? It seems unlikely that both would fail at the same current.

If you're wanting to attempt to fix it yourself, I would suggest a hot gun of some sort, at a low temperature if possible, and try to find an area of the board that seems to be sensitive to temperature. It might be easier once it happens to use a "can of cold" to try to make the problem go away. But it might take a long time for the controller to start producing again, and if it's the microcontroller crashing, it won't recover anyway.

I'd also try to check the shunt resistor (use a current limited power supply and voltmeter), though if the current shunt was high resistance, I'd expect the reported current be higher than 7A.

I have near zero experience with the 24V models, and none with the dual SCC models. Perhaps someone else has.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
bergloewe82
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Re: MPPSOLAR MPPT BOARD defect

Post by bergloewe82 »

Hello,

The temperature visualiced in Watchpower is okay. (30°), also the boards where checked with an IR-Camera. No Hotspots on the visible Boards.

The Current is also correct, (controlled with an clamp)

Yes the inverter has 2 seperate MPPT Boards. Perhaps I crashed the second one after switching to this input.
Thois is the only reason with is possible for me. (Same failure on both boards in short time)

Looking forward for new Ideas....

Are there any Parts inside which are "switched on" in series with increasing Current? If something essential is defect its not possible to "restart" and keep on live with less sun.


BR Stefan
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coulomb
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Re: MPPSOLAR MPPT BOARD defect

Post by coulomb »

bergloewe82 wrote: Mon, 05 Apr 2021, 22:42 Are there any Parts inside which are "switched on" in series with increasing Current?
There are 3-6 MOSFETs in parallel on each channel. It's an interleaved design for these low voltage SCCs. The MOSFETs in each channel would all operate together. But you've jogged an old memory now, I suspect that only one channel is used at low power. If I remember after my appointment, I'll go check if that's true and if so what the threshold is for transitioning to two channels.

So it would be worth comparing the electronics from each channel. You know that one side works, at least at room temperature, and it could well be that the other side is faulty. I dont think that the MOSFETs could be shorted, so perhaps the gate drivers are turning on too slowly, or too long, or are shorting out the power supply when they turn on.

The power supply is driven by the PV input, not the battery. It could be that the power supply is weak, capable of driving one channel, but not two. Maybe it's a capacitor that should be providing most of the peak current for charging the gate capacitance.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
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coulomb
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Re: MPPSOLAR MPPT BOARD defect

Post by coulomb »

coulomb wrote: Tue, 06 Apr 2021, 06:48But you've jogged an old memory now, I suspect that only one channel is used at low power. If I remember after my appointment, I'll go check if that's true and if so what the threshold is for transitioning to two channels.
I can't find that code with a quick search. But I still like the idea that one channel might be faulty, allowing operation up to a point and no further. Why that point might be 7 A, I don't know.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
T1 Terry
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Re: MPPSOLAR MPPT BOARD defect

Post by T1 Terry »

We had one of the stand alone MPPT controllers from the same mob and it would only work in the mornings and late evenings. When we finally got vehicle back to the workshop it turned out to be an over voltage open circuit that was causing the problem. Measuring the open circuit voltage the meter showed 135v, 10v within the maximum upper limit, the problem was the rapid on/off the solar supply by the MPPT controller was causing voltage spikes at around the 155v mark, although probably a lot higher because the meter is a bit slow to register the peak, but I didn't have my CROW available at the time.
I dropped the open circuit voltage down by 20 amps by dropping a panel out of each string using an old towel over the last panel in each string, the problem went away. Meant lifting all the panels to change the number of panels in each series string, but that solved the problem and it never returned.

T1 Terry
Green but want to learn
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