Solar Driven Charge Station

for Mobile Phones etc

Designed to meet the needs for a small self-contained unit for bulk charging mobile phones, music-players etc. The station uses a solar panel (or small wind turbine) to charge battery to magazine energy so charging can be done on rainy, cloudy days or during night time. The station uses USB as unified power interface. USB is a popular common interface for most devices and telephones and many other gadgets. The station is designed for robustness. Chassis is a rugged aluminum case that also serves as heat sink for the power electronics. The design is based on the latest microprocessors technology. and uses powerful components, including high power FET's transistors for power control and versatile Hall elements for current sensing. The unit can be monitored, debugged and configured via USB. This needs a special cable and terminal program on the host computer. This is only intended for service and expert users. For normal operation the unit works out-of-the-box in an optimal way.

System details

System Components

Charge Station Control Unit
Solar Panel
Battery
Suitable USB cables

Charger Features

Algorithm from latest research in charging technology
MPPT Maximum Power Point Tracking
Temperature compensation via external sensors (0.5C accuracy)
Low-Voltage disconnect protection
Current limit (software settable)
Blocking and reverse protection diode input.

USB Power

Ten (5 * 2) Type A connectors with power (5 Volt)
Each two ports are separated for short circuit protection etc.
USB power is disconnected at low voltage for battery protection
USB power can be dis- and reconnected manually.
Uses selected components for very low idle current
Designed for low idle current not to drain battey
Configurable "sleep mode" to save idle power

Connectors

Battery. Red(+) Black(-) Screw Mount. Nomial 12V. Use fuse 5-10 A
Solar Panel. Brown(+) Blue(-) Screw Mount. Max 25V Volt
USB 10 st type A. More 1 Ampere per pair.
Temperature probe for battery

Monitoring

Two LED indicates battery level and charging activity
Special USB connector for "expert" monitoring

Usage and Operating Environment

Although a rugged design the unit should not be exposed to rain and dust. Also allow for air flow and avoid very high temperatures as this reduces the lifetime for the electronic components as switching capacitors.

System Design Guidelines

Size and power rating of solar panel. (30-100W) Max 25Volt
Size and capacity of battery. Nominal 12 Volt.

Overnight charging, sun hours, availabily etc. This section has to worked out...

Battery Handling

The above recommendations also goes for battery as heat causes problems and shortens lifetime for most batteries. The charger compensates for the battery temperature. The sensor should be mounted on the battery.

Application Hints

In areas where the power grid is available but not stable tha solar panel can be replaced with DC power supply to achieve "UPS-like" function. Recommended voltage is 14-20 Volt DC

Troubleshooting

Monitor LED
Measure battery voltage with multimeter
Measure solar panel voltage
Connect USB monitor cable. Use command "ss" status summary

Service and Repair

The unit contains advanced and expensive parts and might be able to be repaired by an authorized dealer

NOTE. Connect battery poles (+, -) correctly otherwise unit might be damaged. Use fuse for battery. Suiable fuses is micro-fuses used in many modern cars.

Firmware Command Example

A short Example

Price

The charge station is yet only available in small volumes. The volume price is investigated.

Further Research and Development

Need for continued product development and further improvement

Other battery types
Ultracapacitor for storage (1500F Capacitor Picture Here)
Further improved energy design

Cavests, Issues

Ericson phone models has many variants and some needs special cables to charge. The charge station only provides power via the USB connector

Contact

robert@herjulf.net (Robert Olsson)