I have just ordered a 25 Watt Sunlinq PV solar panel and I am now looking for a solar battery charger device to store the electrons generated by the PV panel. Found this one but its limited for what it can do for the price.

http://www.brunton.com/product.php?id=604



So I'm thinking of designing my own to the following spec to give maxiumum flexibility, with the design being compact and portable and which can be used around the home together with the motor car in mind as well as for general field use.

Any other thoughts as to what might be useful. I would expect the design to weigh less than 1.5 to 2 Kg and be about the same dimensional size as a 0.8 to 1 litre circular cooking pot.



Specifications for a Portable Solar Battery Charger.

Features:

Input Voltages DC source; 4 - 30 Volts DC

Input Voltages AC source; 110-250V AC (Mains@ 50Hz or 60Hz) input.

Output Voltages DC; Continuous 0-24V DC output in 0.1 Volt Steps (quick menu programmable with standard voltages including 1.5V (for external charging of NiMh and NiCd cells) 3.0V, 4.5V, 5.0V, 6.0V, 9.0V, 12.0V,14.4V (for external charging of Deep Cycle Lead Gel Cells) 18V, 22V and 24.0V; Maximum DC power output typically limited to 40 Watts @ 12 V

Output Voltages DC; Double Standard +5V USB (500mA each) output connections.

Output Voltages AC; 200 Watts Mains Inverter (from external DC source) to both UK European (220/240V AC @ 50Hz) and US (100/127 V AC @ 60Hz) with 40 Watts (maximum) when run directly from the 12 Lithium 16850 Cell Array. Output AC (mains) being selected from the microprocessor control software operational interface.

Microprocessor controlled with 3 button Keypad and 2x8 character Alphanumeric back lit capable LCD display for Voltage and Current Monitoring of the Lithium Cell array together with discharge times and charging times and control of the various output Voltage and Current operational modes described below.

Lithium Ion rechargeable Cell Array 12 18650 3.7V 2200 mAhr Cells giving approximately 98 Whrs. Each Lithium Cell is individually replaceable with easy access within the device.

0.5 Watt PV Solar Cell to provide trickle charge to the cell array when no other DC or AC sources available. (possibly an optional within the design as this would be dependent of the form factor)

Operational Modes:

Lighting Mode - incorporating a lighting circuit with 2 heat sinked SSC P7 LEDS with variable microprocessor controlled output. (Light output for a combined output of 10W would be around 800 Lumen with around 9 hrs use – 2 Watts 150Lumen for 45 hrs use. Turbo Mode lighting would generate up to 1600 Lumen for 3-4 hrs)

Direct AC/DC Supply conversion Mode - to allow the 110-250V (Mains @ 50,60Hz) to be converted to the programmable output voltages (Typical 40W maximum @ 12Volts) allowing the device to operate as an accurate programmable DC PSU.

Direct DC/DC Supply conversion Mode – to allow the input DC voltage (4-30V) to be converted up or down to the programmable output voltages (Typical 40W maximum @ 12Volts)

Inverter Mode – to allow for external DC sources such as from Deep Cycle Lead Gel Cells (6V DC, 12v DC, 18V DC, 24v DC) to be directly converted to Mains AC (either US, UK European standards) to power conventional mains powered equipment (120 Watts Maximum).

Direct Mains Conversion Mode - Regulated US (100-127V@ 60Hz) to UK European (220-240V@ 50Hz) conversion and UK European to US conversion (Maximum 100W).

External Battery Charging Mode for Deep Cycle Lead Gel cells - Microprocessor charge (14.4V) and trickle charge control for external Deep Cycle Lead Cells from either Mains AC input or DC input i.e. Solar PV array.

External Battery Charging Mode (NiMh and NiCd)- Microprocessor charge and trickle charge control for NiMh and NiCd (1.5V) and from either Mains AC inputs or DC inputs i.e. Solar 12 V or 24 V Photo Voltaic array.

Double Standard +5V USB power output connections to allow connection of multiple USB powered devices such as Mobile phones, MP3 players etc which would be completely. Independent of any of the above modes.