Two 100W monocrystalline solar panels are installed on the roof. The MPPT voltage is 18V*2=36v. The nominal no-load value is 21V and the actual value is 25.2V. Two modules reach more than 50V. The ordinary DCDC is not enough to meet my needs. I browsed on Taobao and the circuit module of LT8705 seems to be very NB-looking, and it is very expensive. With that kind of money, it is better to buy a finished MPPT controller. So let’s make one. LT8705 is also not easy to worry about. There are more than 69 new products. It didn’t meet my DIY requirements, so I bought 3 disassembled ones. Yes, all 3 are good. Love it, love it.
Features
■ A single inductor can achieve V IN higher, lower, or equal to V OUT
■ V IN range: 2.8V ( requires EXTV CC > 6.4V) to 80V
■ V OUT range: 1.3V to 80V
■ Quad N- channel MOSFET gate driver
■ Synchronous rectification: efficiency up to 98%
■Input and output current monitoring pins
■ Synchronizable fixed frequency: 100kHz to 400kHz
■ Integrated input current, input voltage, output current and output voltage feedback
ring road
■ Clock output can be used to monitor chip temperature
■ Available in 38-pin (5mm x 7mm) QFN and TSSOP packages
(where the TSSOP package has been modified to improve high voltage operation)
Application
■ High voltage buck-boost converter
■ Input or output current-limited converter
describe
The LT®8705 is a high-performance buck-boost switching regulator controller.
Can operate when the input voltage is higher, lower or equal to the output voltage. the
Device features integrated input current, input voltage, output current and output voltage
Feedback loop. With a wide 2.8V to 80V input and 1.3V to 80V output
range, the LT8705 is compatible with most solar, automotive, telecom and
Pool powered system.
The SRVO pin of LT8705 indicates which feedback loop is currently working.
Under light load conditions, the MODE pin can
Mode®), discontinuous or continuous conduction mode. Other features
Includes a 3.3V/12mA LDO, a synchronizable fixed operating frequency
rate, built-in gate driver, adjustable UVLO, and programmable maximum
Input and output current monitoring functions.
This is my solar panel. Two 100W monocrystalline panels are fixed with stainless steel fasteners and explosive screws.
First of all, when I came back to make a sample, I saw that the color of the board was quite good and beautiful.
Start patch soldering components
The board also needs a powerful cooling system. Large aluminum block and cooling fan.
The double-sided thermal conductive tape used on the back of the PCB is very sticky.
Put into use after final debugging
Since two lithium batteries with different capacities are used, the LT8705 is used to step down the voltage by 20V and then connected to two CN3722 control boards for charging.
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