danjuliodesigns
Power Management
makerPower Solar
An intelligent solar power system for the internet of things
danjuliodesigns
Power Management
The makerPower Solar is a combination intelligent solar battery charger and 5 V power supply. It allows technical professionals and hobbyists to take their embedded systems and Internet of Things devices off the grid and run them anywhere. It can operate as a simple stand-alone power supply or as a peripheral capable of fully reporting power conditions. A true maximum-power point (MPPT) algorithm extracts every joule of energy from all solar conditions.
Discharging a battery too deeply will significantly shorten its life. The makerPower Solar automatically shuts off power when, in the rare case of insufficient solar charging, the battery is low and it automatically restores power after the battery is charged. It provides an alert sixty seconds before power down to allow the user’s attached system to properly shut down (to prevent file corruption, for example). The shutdown and restart thresholds are configurable, allowing the user to make trade-offs between maximum depth of discharge and battery life to fit their requirements.
Reliability of remotely located systems is paramount. The makerPower Solar includes a watchdog timer that can be enabled to power cycle the attached system if it does not periodically reset the timer. The system is given a sixty second alert warning, so it can properly shut itself down before power is removed, if possible.
Interesting things sometimes happen after nightfall. Whether you want to take photographs of things that go bump in the night, or keep the dark away by powering a light or sign, makerPower Solar’s optional night-only power setting has you covered.
The included I²C interface provides access to status, control, measurements, and parameters allowing the power system to be part of the user’s application and data collection. The makerPower Solar also provides Alert and Night status signals that can be fed into GPIO pins or can even used to directly control circuitry, such as a switching transistor.
The makerPower Solar is designed to work with ubiquitous and inexpensive 12 V solar panels and sealed lead-acid batteries, enabling low-cost but high-performance power systems.
Standard 12 V solar panels include 36 cells and typically generate the maximum amount of power when operating at 17-19 V. Originally designed to be directly connected to 12 V batteries operating at the battery voltage, these panels are more efficiently used by the makerPower Solar’s MPPT charger that keeps them producing as much power as they can over the full range of illumination levels. The MPPT charger works by controlling panel current so that the panel voltage is kept at the optimum level (output power is maximized). It constantly makes small adjustments to the panel current to keep it tracking the maximum power transfer point as light levels change. A switch-mode voltage converter efficiently converts the varying higher voltage from the panel to the lower voltage and higher current used to charge the battery. The makerPower MPPT charger provides an additional 20-25% charging energy over directly connecting a panel to the battery and allows continued extraction of energy from low-light conditions when panel voltage would have collapsed for a direct connection.
While lead-acid batteries often compare poorly with more modern battery technologies in specification comparisons, they still remain an ideal choice for this class of solar system. The Absorbent Glass Mat (AGM) battery is commonly used by commercial uninterruptible power supplies, which means it is inexpensive and available in a variety of capacities. Running a system like a Raspberry Pi 24 hours a day from solar energy requires far more capacity than inexpensive lithium batteries can provide. Large capacity lithium batteries are much more expensive than comparable lead-acid batteries. For example, a 9 Ah 12 V LifePo4 battery is five times more expensive than the equivalent AGM battery. In addition, lead-acid batteries are better suited to outdoor operation over a larger temperature range. Lead-acid batteries can charge over -20°C - 50°C while lithium batteries are limited to 0°C - 45°C. The makerPower Solar provides temperature compensation for the charge voltage level to maximize battery life.
Use a remote webcam for security or to watch wildlife. makerPower Solar provides enough power for a Raspberry Pi-based camera plus communication mechanisms including Wi-Fi, cellular, and even satellite modems.
Exciting new communication technologies such as LoRaWAN® and inexpensive cellular network development boards (like the Particle Boron) make it easier than ever to remotely locate all kinds of sensors. With makerPower Solar, it’s easy to power them.
Sometimes you just need some remote power and makerPower Solar has you covered there as well.
The makerPower Solar came about as the result of feedback from a previous intelligent solar power product. Customers wanted true 24/7 solar operation at a cost-effective price-point. Implementing the charge controller in firmware on an inexpensive micro-controller instead of dedicated and expensive silicon allows the makerPower Solar to provide a high level of functionality at a great price.
| makerPower | PiJuice Solar | SunDuino | LiFePO4wered/ Solar 1 | SunAirPlus | Morningstar SG-4 | |
|---|---|---|---|---|---|---|
| Maximum Power Point Algorithm | Dynamic - adjusts for panel and light level | No | Fixed at one level | Fixed at one level | Linear MPPT Approximation | No |
| Max Charge Capacity | 40 W | 9 W | 15 W | 10 W | 6 W | 51 W |
| Max Battery Capacity | 317 Wh | 44 Wh | 230 Wh | 48 Wh | 24 Wh | 500 Wh |
| Battery Type | SLA | Li-Ion / LiPo | SLA / Li-Ion / NH | LiFePO4 | Li-Ion/LiPo | SLA |
| Temperature Compensation | Yes | Yes | No | Yes | No | No |
| Max 5 V Out | 10 W | 12.5 W | 10 W | 10 W | 5 W | - |
| Auto Shutdown/Restart | Yes | Yes | No | No | No | No |
| Computer Interface | Yes | Yes | Yes | No | Yes | No |
| Software Support | Yes | Yes | Yes | No | Yes | No |
| Remote Monitoring | Yes | No | No | No | Yes | No |
| Price | $42 | $45 | $29 | $17 | $45 | $33 |
The makerPower Solar board is well supported with documentation, software, and example integrations. You can even gain insight into its design by reading the project history.
Board assembly is done by our contract manufacturer in China using parts sourced through American distributers. We have been working with this manufacturer since 2016 to manufacture other designs. They assemble and test the boards using a manufacturing test and programming fixture that verifies board functionality and performance, loads firmware, and performs calibration.
The manufacturing test fixture provides a print-out with diagnostic information that can be used by technicians to investigate and repair failing boards.
All orders are delivered using Crowd Supply’s fulfillment service. For more information, please see Crowd Supply’s Guide on ordering, paying, and shipping.
The battery offered is only available to ship within the USA at this time.
"The idea of using lead-acid batteries is that they are much cheaper that Li-Po or Li-ion batteries, and can function in nearly any inclement weather and temperature ranges without failure."
"If you are considering building a solar project you might be interested in a new intelligent solar power system designed specifically for the Internet of Things"
Produced by danjuliodesigns in Boulder, CO.
Sold and shipped by Crowd Supply.
One makerPower Solar Board. Comes with a spare fuse and a 6-pin header.
This wiring kit includes nine 20 cm female-female Dupont wires, two 20 cm battery wires, and a header to make the temperature sensor remote.
From the Crowd Supply Basics project.
One 9 Ah battery.
Boulder, CO · danjuliodesigns.com
I currently design embedded systems. In the past I designed ASICs for computer graphics systems and computer servers as well as ASIC verification software.
