Desired NinjaSCC Specs to have a common frame of reference during design and documentation phase.

NinjaSCC will by default fall into a 12V system. Any other check, charge, equalize and float setpoints can easily be overriden in software to leave more headroom for all kinds of use-cases and many battery types like lead-acid, gel,agm and lithium battery packs in the 12V to 36V range.

Output Current/Voltage ripple and RF noise need to be kept at a minimum, to increase battery lifetime and allow RF sensitive devices, like remote SDRs, to be powered by NinjaSCC as well.

10-bit ARef 5V (Arduino) 12-bit ARef 5V (4 channel external ADC via I2C)

• Short-Circuit [HW]
• Over-Voltage [HW+SW]
• Over-Current [HW+SW]
• Adjustable Current Limiter [HW+SW]
• LVD (Low-Voltage Disconnect of Load) [SW]
• UVLO (Under-Voltage Lock-Out) [HW]
• Uncontrolled Back-Channel DC GND return (High-Side Load Switch) [HW]
• Electromagnetic and Lightning induced extraneous Voltage Transients [HW]
• Local ESD [HW]

• Battery Temperature Monitoring (via external 100k thermistor)
• PV Panel Temperature Monitoring (optional)
• PCB Temperature Monitoring
• Over-Temperature controlled Shutdown
• Fan-Control
• Assembly PU-Coating

Based on real-time assessment of the operating conditions, NinjaSCC dynamically determines the optimal operating mode in order to track the maximum power point of the PV panel, keeping overall conversion efficiency close to 99%.

• MPP Tracking Buck-Only (BK)
• MPP Tracking Boost-Only (BST)
• MPP Tracking Buck-Boost-Interleaved (BB)
• Transit (TR)

Since Arduinos have been around for a while and have a very broad spectrum of documentation, HOWTOs and open-source code to learn from, the AVR ATMega32U4 8-Bit Microcontroller (with built-in USB support so that we can give FTDI the finger) was chosen as the main controller in a fully Arduino-Micro compatible configuration, while adding a couple of protective features to it. This way, NinjaSCC can be used and flashed over USB like any other Arduino-Micro board.

As other USB power sources, like most wall warts and auto adapters, NinjSCC does not enumerate the USB output port. Charging can begin immediately, without any digital communication/negotiation, as defined in the supplementary USB Battery Charging Specification, Rev 1.1, 4/15/2009 (BC1.1).

• Supply 5V up to 1.5A
• DCP mode identified by a short between D+ to D-
• Short-Circuit, Over-Voltage, Over-Current, Over-Temperature protected
• Shares EN pin with Load Switch to maintain LVD ability by default,

but can be selected with a solder bridge/0R

Constantly monitor and collect all relevant system metrics and operating parameters and deliver a high-resolution, real-time metrics stream over USB to be live-viewed and/or shipped into a metrics storage engine like influxdb to achieve full real-time, remote system awareness, gather long-term data to optimize the system even further and have a means to analyze/identify sub-optimal operating conditions which might lead to failure like: Battery temperatures that are consistently above ambient may indicate high ripple, overcharging or internal cell shorting.

Any DC/DC regulation parameter can be overriden in software by remote controlling NinjaSCC over USB, so playing and experimenting on a live, working converter with instant metric feedback will be a great opportunity to study its behaviour while changing parameters and operating modes manually. And of course, a fun and hands-on learning assistance while teaching buck/boost technology to others.

Designed in a built-to-last approach, almost all components have been selected in a range between automotive qualified and up to aerospace/military grade quality. A non-profit approach is the key here, because this way the focus gets back where it should belong: On the product and the component quality it is made of. With attention to detail and without undue compromise.

To further decrease the chance of total system failure, most important system blocks and components have been set up n+1 redundant, wherever possible and reasonable.

NinjaSCC must withstand gale force sub-arctic winds at -40°C while still providing power to the camera you’ve put out there for over a year, to make a movie about glacier calving or you are in a remote desert at +55°C ambient temperature and need power to operate your water pump.

When you’re truely off-grid, this is the device that must not fail (or at last reasonably max out the chance that it does), because murphy dictates: it usually does so at the worst possible point in time.

First concept:

MKI early:

MKI latest: