Embedded techniques engineer Juan Flores has constructed a compact little board designed to make it simpler so as to add solar energy to your subsequent construct: the Photo voltaic Buck-Enhance module.
“This mission is a module that permits charging a Li-Po [Lithium Polymer] battery from two completely different vitality sources and offers a continuing output voltage unbiased of the battery voltage, with minimal losses to make sure long-lasting operation in low-power purposes,” Flores explains. “It really works accurately with a photo voltaic panel, therefore its identify.”
The compact board, which has a USB Sort-C connector at one finish, a battery connector on the high, voltage output pins on the different finish, and a screw terminal for a photo voltaic panel on the backside, is constructed round two core units: the Consonance Electronics CN3063 lithium-polymer charging chip and a Texas Devices TPS63020 for dealing with voltage regulation on the output.
“This element may be very attention-grabbing,” Flores writes of the TPS63020, “because it permits configuring the output voltage based mostly on the voltage divider related to the suggestions pin (pin 3). The datasheet already provides some values for a 3.3V output, which is what I used to be initially in search of, however we might mainly go away the 180k resistor and alter the 1M resistor to acquire completely different voltages, equivalent to changing the 1M resistor (R4) with a 1.6M one for a 5V output.”
The charging circuit acts as an N-type MOSFET with the drain related to the photo voltaic panel and the gate to the USB enter: if energy is current on the USB connector it’s robotically used to cost the battery, and if not the photo voltaic panel is used as an alternative.
Flores has launched KiCad mission information for others to construct their very own photo voltaic modules. (📷: Juan Flores)
“It will work with photo voltaic panels from 4.5V to 6V, however ideally, a most of 5V needs to be used,” Flores writes, for the straightforward motive {that a} photo voltaic output larger than 5V would take precedence over the USB connection.
“Additionally, the charging pace will depend on the panel’s energy. The one I exploit is 0.2W at 5V, that means it generates 40mAh at full efficiency, so it could take 10 hours in full solar to cost a battery just like the one in [my] video (500mAh).”
The complete mission write-up is offered on Hackaday.io, with KiCad mission information and schematics out there on GitHub beneath an unspecified license.