In a real world test of a MISO unit, conditions beyond those specified in the data sheet for the Power Integrating module with Pulsed Driver were encountered. If you recall, the POWIM-PD is recommended to be operated with 15 V DC maximum at the inputs. In this test our POWIM-PD encountered voltages above 20 V DC and survived it.
The test involved a power system comprised of a 3000 W generator and a set of solar panels. The problem that the MISO was being used to solve was in the wiring requirements of this hybrid power system. The solar power system is permanently wired to the storage batteries to provide charging current. However, when it is operating the generator can also be used to charge the batteries. To capture this extra energy, it was necessary to manually connect the generator into the charging circuit before starting it up, collect the charging energy, and then manually disconnect the generator from the wiring when it was shut off. The reason for this was that the generator is rarely used, but when it is used it would be inefficient to waste the opportunity to make use the of costly gas for battery charging. The MISO could solve the problem by switching the generator into the charging circuit when it is running and switching it out when it is not running.
The generator battery charging circuit is essentially an alternator and it is rated at 13.5 V DC. The solar panels are rated at 15 to 20 V DC. On this day however, the generator was providing 25V DC and the solar panels were providing more than 20 V DC. Obviously, the generator is out of spec but this was not known about the DC charging output until after the MISO had been connected and the test initiated.
The generator was connected to the Main Input of the MISO and the solar panels were connected to the Secondary Input. The Output of the MISO was connected to the batteries' charge controller. When the generator was started, 25 V was measured at the the output of the MISO and the generator was effectively charging the batteries. When the generator was shut off, 20 V was measured at the output of the MISO and the batteries were being solar charged. The test involved cycling the generator on and off several times and during the test the MISO switched to the generator battery charging circuit every time the generator was on and switched to solar panel panel battery charging whenever the generator was off.
Through this test the POWIM-PD circuit inside the MISO has proven that it can function outside of its specifications and that it can survive some tough conditions in the real world. The MISO unit came through the stress still functional. 8 Amps is the maximum current provided by the generator charging circuit and perhaps this condition was responsible for the MISO's survival. MISO inputs are rated for 12 Amps. It is the power, the product of current and voltage, that determines how stressed a device truly is. At the power level encountered in the test the MISO could possibly have stayed in this out of spec battery charging circuit for a long time without being burnt out.