...
| View file | ||||
|---|---|---|---|---|
|
| View file | ||||
|---|---|---|---|---|
|
Testing Results
TEST SETUP:
(It was a lot brighter than the image shows. Each lamp is a 500W halogen lamp, for 2000W total)
Below are shown the graphs produced form the tests, the tests with single panels were completed with all 4 halogen lights shining on a single panel:
Panel Only
1 Panel, 1 MPPT
2 Panels, 2 MPPTs, Parallel (with regular diodes on outputs of individual MPPTs)
2 Panels, 2 MPPTs, Series
| Condition | Vmpp (V) | Impp (A) | Pmpp (W) | MPPT Power Loss | MPPT Efficiency |
|---|---|---|---|---|---|
| Panel Only | 15.028 | 0.829 | 12.452 | ||
| Panel With MPPT | 14.638 | 0.802 | 11.739 | 0.713 | 94.3% |
| 2 Parallel | 17.727 | 0.732 | 12.982 | ||
| 2 Series | 30.648 | 0.44 | 13.477 |
Notes - there was 'a little' more light for the 2 panel tests since the ambient lights were on both panels as well. During the single panel tests, all the light was concentrated on a single panel, thus giving higher per-panel output in the single panel tests.
SPI Testing
With all of our SPI testing with the power supply as the power source and not much success, I finally decided to just go for testing with the panels. And since we finally have lights that can at least give us some power, we were able to test it.
I swapped in a Nomura with the SPI-GND jumpers cut and probed the registers using Arshan's mppt-spi program. The resulting text file is added below.
With the panel, SPI worked amazing. The weird jumps in the input voltage values that we had seen with the power supply are no longer there. The values were changing almost continuously to maintain the maximum power point. Everything seems to be working well.
We also tested an undervoltage cutoff and restart - We loaded the output until the MPPT went in to pass through mode, then continued increasing the load until the panel voltage dropped below the UVLO voltage where the chip shuts off. At this point, we received all 0's over SPI. When decreasing the load, the MPPT turned back on, starting in pass-through mode, and went into MPPT mode when the input voltage was high enough. It worked flawlessly and went straight in to the MPPT algorithm.
At this point, I don't see what we could have done wrong during FSGP 2019 except for some weird wiring error that was never caught, and I'm starting to think more and more that this was actually the issue.
| View file | ||||
|---|---|---|---|---|
|