24/7 Power for your remote projects

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 locate 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.

Smart Features Make your Job Easier

Auto-shutdown/Restart with Alert

Too deeply discharging a battery will significantly shorten its life. makerPower Solar automatically shuts off power when, for the rare case of insufficient solar charging, the battery is low and 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.

Watchdog Timer

Reliability of remotely located systems is paramount. 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.

Night-only Mode

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.

Two Digital Interfaces

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. 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.

Power and data direct to a Raspberry Pi.

Simple switch for night-time LED lighting.

Cost Efficient Power

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.

Solar Panels

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.

Battery Chemistry

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. makerPower Solar provides temperature compensation for the charge voltage level to maximize battery life.

[Inexpensive] power enough for days...

Use Cases

Remote Webcams

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.

Enclosure design documented on Github.

Sensing Applications

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. makerPower Solar makes it easy to power them.

Radiation Monitor with Particle Photon.

Remote Power

Sometimes you just need some remote power and makerPower Solar has you covered there as well.

Light the way to your favorite joint.

Specifications

Dimensions
- 85 x 56 mm (same size as Raspberry Pi 3)
- Mounting holes align with Raspberry Pi boards (including Pi Zero)
12 V Operation
- Designed for 36-cell solar panels (typ 25-40 W)
- Works with sealed AGM lead-acid batteries (typ 7-18 Ah)
35 W MPPT Charger
- Dynamic Perturb & Observe algorithm
- Three state charge: BULK, ABSORPTION, FLOAT
- Temperature compensation
Dual Outputs
- 5 V 2 A (10 W) managed output available from USB Type A socket for plug&play with many devices or from a 0.1” header for direct connection
- Fused and current monitored 12 V (3 A maximum) battery output available from a header
Digital Interface
- I²C slave interface
- Alert logic signal to notify of impending power-down
- Night logic signal asserted when solar panel is dark
Detachable temperature sensor for battery temperature monitoring

Comparisons

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	$40	$45	$29	$17	$45	$33

Support & Documentation

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.

Manufacturing Plan

Board assembly is being done by our contract manufacturer in China using parts sourced through American distribution. We have been working with this manufacturer since 2016 to manufacture other designs. They will 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.

Fulfillment & Logistics

All orders will be delivered to backers using Crowd Supply’s fulfillment service. Delivery within the US is included in the listed price while delivery outside the US will incur the shipping surcharge listed for each pledge level. For more information, please see Crowd Supply’s Guide on ordering, paying, and shipping.

The battery offered during this campaign is only available to ship within the USA at this time.

Risks & Challenges

The makerPower Solar design is finished and has been validated with over a year’s worth of operation in several locations across the USA. Supporting documentation and code have been written. The manufacturing flow, including the test and programming fixture, has been established. The manufacturing partner has been used for a previous product.

As with many electronics devices, the primary risk has to do with component shortages. makerPower Solar was designed with manufacturability in mind. Substitutes exist for many parts on the board. Orders for parts will be made when the campaign launches.