DIY REWIRING & EXPANDING SOLAR PANELS; CHARGING CELLULAR OR 5V DEVICES VIA USB;
MATCHING THE OUTPUT POWER OF A WALL CHARGER VIA SOLAR PANELS DIY ASSEMBLY & INCLUDES BASIC SOLDERING TIPS”
The ebay link below is a great recourse for purchasing quality hand made solar cells. This article is based on these specific solar cells, or solar cells of a similar design.
Each solar panel unit is 5V, 0.55A, 2.75W, (8.8″ x 3.4″ Inches) with a USB2.0 plug for power.
Each Solar Panel comes equipped with the ability to individually charge your cell phone or power bank; via USB. A single solar panel listed above is rated at [5V, 0.55A,] and will charge significantly slower than a standard USB [5V, 2A] wall outlet charger. However if you want to modify your solar panels to match total output of a standard USB wall outlet charger; you will need to expand the total capacity by wiring “4” solar panels together in parallel.
(See attached DIY_SOLAR_ EXPANDING_ASSEMBLY.pdf for visual instructions to the following article)
Tools And Supplies Needed:
Solar Wiring Specs:
Connecting solar panels in “parallel” will increase the total solar panel capacity or amperage(A) while maintaining the same voltage(V). Parallel wiring essentially connects a positive terminal from one panel to the positive terminal of the consecutive panel. The same rule applies for the negative terminals; negative terminals connect in succession to the neighboring negative terminal. Think of parallel wiring as; each solar panel working in a “team” of passing current to the next panel. If one panel in the unit “fails” the current will pass over the faulty panel to allow the others to still output power.
“(Example): (4) 5V , 0.55A solar panels wired in parallel have an output of 5V, 2.2A; a total of 11W of power; instead of 2.75W that only 1 panel provides.
5 x 1 = 5V (Voltage stays the same because parallel wiring creates a single solar unit rather than 4 individual solar panels.)
0.55 x 4 = 2.2A (Amperage increases because we are multiplying the amperage of a single panel by the amount of panels used in the group.
2.2A x 5V = 11W (Total power)
Connecting the leads properly in “parallel” is crucial to an intentionally functioning solar panel unit. Be aware to not wire your panels in “series” for this specific application. Accidentally wiring in series would result in multiplying the voltage and will overload the device you are charging. Wiring in “series” would require the positive terminals to connect to the negative terminals of the neighboring panel. However for this specific application; it is crucial that series wiring does not happen.
Basic Soldering Knowledge:
Before you start the wiring process; it is important to have some basic knowledge on soldering. Be aware that soldering irons can be dangerous and harmful if not handled properly. Never hesitate to research for assistance if you are not comfortable using a soldering iron.
> Pick a well ventilated and dry workstation with no flammable debris. Soldering irons can reach temperatures of +800°F and can easily burn or cause fires if not handled carefully.
> Smoke from soldering can be harmful if inhaled. Please use proper ventilation, eyewear, and face-mask when soldering.
> When using a new soldering iron or installing a new soldering tip; It is important to “pre tin” your soldering tip before its first use. In high temperatures: soldering tips are easily oxidized when exposed directly to the air. Immediately applying soldering flux and solder to a new heated tip will adhere and cover the soldering tip to prevent oxidation and long-term damage.
> Pre tinning the soldering iron tip is a necessary routine for every time the soldering iron is in use. Pre tinning the soldering iron will also allow the direct soldering process and solder to adhere to whatever you are soldering.
For further tips on soldering; please visit this youtube Link. This video and YouTube Channel are great resources for electronics assembly knowledge. One of the top soldering iron manufacturers: “Weller” has detailed read along resources available on proper soldering procedures: Weller Recources
See; “DIY_SOLAR_ EXPANDING_ASSEMBLY.pdf” for visual examples to the following steps.
Take 4 solar panels and desolder the leads directly connected to the USB port using a soldering iron. Only the usb ports should be removed. When desoldering the USB port terminals; use a quick amount of applied heat from the soldering iron tip to the terminal joints. This will quickly liquify and disconnect the previously made solder joint. Solder has a quick melting threshold and should liquify the previous connection very quickly. Be sure to apply direct heat from the soldering tip. Be aware: unnecessary and long term applied heat may damage electronics. Once detached; set aside and save the usb ports. One of these USB ports will be re-soldered and used to complete the project. Be sure to keep note of which terminals on the USB are positive and negative. This is crucial information to know when re-soldering the USB back on. Be aware: wires directly connected to the solar panels should not be desoldered. “ONLY DESOLDER THE USB CONNECTIONS”.
Flip the 4 solar panels so that the glass is facing down and the back of the panels are facing up to view the back wire leads. Place the panels in an orderly row; touching side to side so that all negative and positive leads are on the same side as each other. Example; all positive leads should be on top, and all negative leads should be on the bottom. (The red wire is the positive lead, and the black wire is the negative lead). With kapton tape; adhere the panel edges so that all 4 panels are held together with tape.
Now that all panels are side by side; cut off two strips of solar busbar ribbon; about 3/4 the length of the 4 solar panels. The length of the busbar ribbon does not need to be an exact measurement. The solar busbar wire ribbon will act as an electrical bridge that unifies all the negative leads together; as well as separately all the positive leads.
Take the negative lead end of the first solar panel, and the end of a cut solar busbar ribbon, and place them on top of each other. Prep the two areas by applying flux to the busbar and the negative bare wire to ensure a good adhesion when soldering. Flux prevents oxidation and allows copper to adhere by flowing a filler metal in between the connection. With a hot and pre tinned soldering iron; touch the soldering iron tip to the negative lead that is stacked on top of the busbar ribbon end. The heated area will quickly flow with metal and form a smooth connection. This will adhere the negative lead to the end of the busbar strip.
By continuing to solder the positive ends to other positive ends is essentially what parallel wiring is. For all parallel wiring applications; do not cross solder the positive and negative leads together. The positive bus bar and wires connected should be unified and separate from the negative busbar and leads. Connecting the positive and negative leads and or busbars together can cause an accidental boost in voltage or an electrical short.
Continue to solder the rest of the negative leads to the same busbar wire using the same soldering techniques. The rest of the negative leads should be spread out evenly across the rest of the negative busbar wire. Be sure to leave at least 1cm of room at the end of the busbar . This same application method and busbar wiring should be a applied for the positive lead connections as well. At this point there should be two parallel busbars running across the back of the solar unit with all corresponding leads connecting to them.
Take a desired amount of 24awg wire and strip the silicone coating off of each end to expose the bare wire. Twist and tin the tips of each bare wire end. Solder new leads from the end of each busbar directly to the corresponding positive or negative terminal on the USB unit. The end result should essentially be a 4x version of the original solar panel with a [5V, 2.2A] output.Like (0)