February 2010, Plane Space Design

The Multiple Input Single Output (MISO) device continues to amaze as it has provided one of its most surprising and unexpected results to this day. The device has caused LEDs that were no longer working in the system that they came packaged with, to come alive. It happened when testing solar powered spotlights that had ceased to function. Two of the lamp units had been burned out due to causes that were not known, but it looked as if a power surge was to blame. After testing the rechargeable batteries and the solar charger and controller it was discovered that these parts were working fine. This was evidenced by the the fact that the third lamp in the 3-lamp system worked when plugged into the power source. Two of the lamps would not work when they were plugged into the same power jack alone. They appeared to be dead to the system that they were packaged with.

Then the MISO came to the rescue. A proposed test of the pulsed driver in the MISO as a source of power for residential solar lamps was already being considered when the lamps failed. Suspecting that the solar illumination kit's batteries were at fault or the charge controller was broken, the MISO was connected to one of the lamps to see what would happen. The lamp came on; but it was later discovered that the kit's batteries were good, the charge controller worked just fine, and the lamp that the MISO had lit up was one of the two dead lamps.

The solar spotlights are made from three bright white LEDs per lighting unit. There are three lighting units, or spotlights, in a kit. Three rechargeable NiMH batteries charge from sunlight in the daytime and at night they power all three of the spotlights. The total battery voltage is about 3.6 V and it is connected across all three of the spotlights in parallel. Because two of the lamps are burned out, none of the lamps will work when all three are connected to the solar power unit. Remove the two burned out spotlights from the power and the remaining spotlight comes on, proving that the power unit is in good shape.

The MISO was connected by wire leads to a 12 V outlet on a solar panel charge controller. The MISO unit was operated single-sided with  the 12 V source connected to the Secondary input terminals. Long lead wires were connected from the pulsed driver screw terminals to go to the lamps. When the burned out spotlights were powered from the MISO pulsed driver output they began to glow at about half of the brightness they had before they burned out.

Why this is happening is not yet understood. Perhaps the LEDs in the spotlights are not completely burned out, but only weakened below the threshold for operation by the kit's solar charger and batteries. Whatever the cause, to the kit they came with these lights are dead, but the MISO has given them a new life in which they can shine on. A surprising and very exciting discovery.