The poster has some questions, let me answer them one by one
Q: When you use a 9V solar panel to charge a 3.7V 800mah lithium battery, what type of voltage stabilization should be added between the two?
A: It's very simple if the requirements are not high. It is acceptable to divide the voltage directly across two resistors. High school level using Ohm's law is sufficient.
Q: The voltage input of the solar panel voltage stabilization module is unstable. Can the voltage stabilization module output 5V stably?
A: If the solar panel in the poster is a qualified product, the output should be 9V, not 5V.
Q: Is 5V suitable for charging 3.7V lithium battery?
A: This is not suitable in theory, but there is no problem in actual use. Many mobile phones now use chargingnt USB 5V.
Q: What is the approximate voltage fluctuation range of my 9V charging board?
A: This question requires checking the specific operating parameters of your battery panel, so it is difficult to answer directly. If you have an oscilloscope, you can measure the voltage floating range of the power supply yourself.
Q: Is the 9V charging board suitable? If not, how can I replace it?
A: It is not possible to charge a mobile phone. 9V is too higher than the charging voltage of a mobile phone battery and is not safe.
Homemade solar panels?
There are ready-made ones on Taobao. I will give you the card and the original model. Take a look.
This circuit combines boost output, solar charging, charger charging, with functions such as battery function display and a pratic, users can change the settings and even the size according to their actual needs. The USB output port is more suitable for universal data cables. USB + DC dual port design, more combination options.
Typical parameters
Input voltage: 0.9V-5V, suitable for use with lithium-ion batteries, nickel-hydrogen nickel-chromium rechargeable batteries, lead-acid batteries and various dry batteries. batteries
Constant voltage output: 5.6V
Output current: MAX800MA
Battery display: red 0-50% energy, orange 50-85% energy, green 85-100% energy
You can change the resistance value of R5/R6 to set the energy display percentage according to your personal preference p>Conversion efficiency: MAX 88%
Dimensions: 20*45MM
Charging method: solar charging + DC port transformer, DC port USB charging
p>
Typically made of monocrystalline silicon or polycrystalline silicon cells, regardless of the size of the single-chip battery in the sun. The power generation voltage is about 5V, and the voltage decreases when the light dims.
Material preparation: two transparent acrylic sheets (1-3mm thick), mobile phone size< /p>
Multiple battery slices (batteries connected in series according to the voltage you need slices to determine the number of slices. Determine the size of each piece based on the power required, usually around 1.7 W/decimeter square)
Two power cords and several electrodes for soldering the battery parts
Transparent glass glue or electric glue stick (after the battery piece is welded, place -the face down in the middle of the acrylic The first and last two welding rods protrude from the acrylic plate, p.then the sealant is aligned and compacted with another piece of acrylic)< /p>
The process will not be detailed, you know
It is recommended to purchase small cells cut with soldering tapes, which are cheaper and more practical
that I made. two, and there are a lot of cells for sale (the quantity you want is only about ten or twenty yuan. If anyone makes solar cells in your city, they can give you free samples) < /p>
It takes 11 -12 cords to charge a cell phone. Each piece can be 5 to 10 square centimeters. The soldering wire is connected in series through the wire and the mobile phone adapter and can be used to charge the mobile phone directly under the sun.