I first came across Texas Instruments BQ24074 while looking at Adafruit's Universal USB / DC / Solar LiPo charger, which replaced their earlier MCP73781-based charger. It's relatively inexpensive ($0.81) and has an input voltage of up to 10V. Unfortunately this chip was out of stock when I ordered my board for SMT assembly,. Analog Device's LT3652 is used in Sparkfun's Sunny Buddy(MPPT Solar Charger), but it's a lot more expensive (around $5) than other chips and was also out of stock at the time of. Consonance Electronic's CN3065 is used in Seeed Studio's LiPo Rider boards, as well as many low-cost solar battery charger boards on eBay.
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What is solar to battery charging efficiency?
The solar to battery charging efficiency was 8.5%, which was nearly the same as the solar cell efficiency, leading to potential loss-free energy transfer to the battery.
What is a solar charger and how does it work?
Solar chargers are increasingly gaining momentum with government agencies pushing towards a greener solution through the use of energy derived from renewable sources. A solar charger mainly functions on the principle of harnessing the energy from the sun and utilizing it to supply electrical energy to devices or for charging batteries.
These solar cells should be able to charge one 1.2 volt, battery, or two 1.2 volt batteries in series at a rate of 20 mA for 200 mAh battery, 30 mA for a 300 mAh battery, or 60 mA for a 600 mAh battery. The charging circuit for these batteries is simple, a solar cell connected to a diode then connected to a NiCad battery.
In our case, the solar cells will not overcharge the battery. These solar cells should be able to charge one 1.2 volt, battery, or two 1.2 volt batteries in series at a rate of 20 mA for 200 mAh battery, 30 mA for a 300 mAh battery, or 60 mA for a 600 mAh battery.
Solar panel 130W in full sun Provide system with 1.3 kWh charge in 10 hours Battery Two 12V@55AHr Storage capacity for 1.3 kWh of charge Lighting 2x5W@6hrs 60 Wh (assumes 6 hours of light) 12V@2A 24W 576 Wh (assumes 24-hour usage) Solar MPPT Battery Charger for the Rural Electrification System AN2321
Are solar chargers portable?
Although the solar charger industry has been plagued by many companies manufacturing solar chargers, most of these are based on the concept of traditional grid infrastructure with permanently installed units. Very few have ventured into portable solar units.