A solar panel is a collection of solar cells. Lots of small solar cells spread over a large area can work together to provide enough power to be useful. The more light that hits a cell, the more electricity it produces, so spacecraft are usually designed with solar panels that can always be pointed at the Sun even as the rest of the body of the spacecraft moves around, much as a tank turret can be aimed independently of where the tank is going.
How to Wire Solar Panels in Parallel or Series
When connecting multiple solar panels in a 12-48 volt off-grid system, you have a few options: parallel, series, or a combination of the two. In this article, we’ll give you the basics on wiring solar panels in parallel and in series. Let’s start off with a quick comparison of parallel circuits and series circuits.
Parallel circuits have multiple paths for the current to move along. If an item in the circuit is broken, current will continue to move along the other paths, while ignoring the broken one. This type of circuit is used for most household electrical wiring. For example: when you turn off your TV, it doesn’t also turn off your lights.
When wiring solar panels in parallel, the amperage (current) is additive, but the voltage remains the same. eg. If you had 4 solar panels in parallel and each was rated at 12 volts and 5 amps, the entire array would be 12 volts and 20 amps.
Series circuits have only one path for current to travel along. Therefore, all the current in the circuit must flow through all the loads. A series circuit is a continuous, closed loop – breaking the circuit at any point stops the entire series from operating. An example of a series circuit is a string of old Christmas lights – if one bulb breaks, the whole string turns off.
When wiring solar panels in a series, the voltage is additive, but the amperage remains the same. eg. If you had 4 solar panels in a series and each was rated at 12 volts and 5 amps, the entire array would be 48 volts and 5 amps.
Remember: just like batteries, solar panels have a negative terminal ( – ) and a positive terminal ( + ). Current flows from the negative terminal through a load (current consumed by a piece of equipment) to the positive terminal.
Wiring Solar Panels in a Series Circuit
- Connect the positive terminal of the first solar panel to the negative terminal of the next one.
- eg. If you had 4 solar panels in a series and each was rated at 12 volts and 5 amps, the entire array would be 48 volts at 5 amps.
Wiring Solar Panels in a Parallel Circuit
- Connect all the positive terminals of all the solar panels together, and all the negative terminals of all the panels together.
- eg. If you had 4 solar panels in parallel and each was rated at 12 volts and 5 amps, the entire array would be 12 volts at 20 amps.
How to Charge a Battery with a Solar Panel – Components of a Solar Power Battery Charger
It’s easy to capture and store the energy freely provided by the sun in a battery. Because it only requires a minimum of equipment, you’ll be able to have safe and clean power wherever you need it. This article is about how to charge a battery with a solar panel.
Many online stores, as well as local hardware stores, have the required equipment to charge a battery with a solar panel. A small system is both efficient and portable. It can be installed in your yard, near a tent, on a boat or in any location that has direct sunlight.
Four pieces of equipment are required for this solar power system to work:
1. A Solar Panel
Select a solar panel with the highest possible power rating while still being easy to carry and handle. Solid panels are more rugged and produce more power than the flexible ones, but are not as portable.Most panels are rated at 12 volts and are fairly inexpensive. For better performance, a 16-volt panel will produce more current and will charge the battery faster.
For do-it-yourself types, you can also build your own solar panel.
2. A Charge Controller
For smaller systems, a charge controller is not necessary, but the relatively inexpensive cost more than justifies the added performance and protection. These units will automatically disconnect the battery from the solar panel once the battery is fully charged. A unit with a maximum power point tracking (MPPT) circuit will also maximize the energy from a solar panel. Make sure that the controller can handle more than the peak amount of current from the solar panel. If more than one panel is used, make sure that it can handle the total amount of current from all of the solar cells put together.
3. A Battery
The larger the battery, the more energy it can store. Look for a 12 V deep cycle battery that can withstand the numerous charge and recharge cycles. These batteries were designed to be fully discharged and then replenished without any damage to the electrolytes or internal plates. Car batteries are not designed to be repetitively drained and will soon fail to hold any charge if used in this manner.
4. An Inverter
The DC voltage of the battery is 12 V but most household appliances run at 120 V AC. An inexpensive inverter, similar to ones that plug into a car’s cigarette lighter, can be used to make the stored energy in the battery usable to your household devices. The current rating of the device should be enough to accommodate your load. Look for one with the number of sockets you will need.
How Long Does It Take To Recharge A Battery?
Depending on the size of the battery, it will usually take a minimum of 5-8 hours to charge a dead battery from a solar panel that produces 1 Amp of current. In order to most effectively charge a battery with a solar panel, you need to maximize the amount of current by keeping the panel pointed directly at the sun. Try different locations in your yard or repositioning the panel every few hours to maximize the amount of sunlight. If you really get into solar power, there is even a device called a solar tracker that will automatically turn your solar panels to the sun for maximum effectiveness!
Here’s a handy little video that shows you the basics – we plan to produce our own soon, but in the meantime, this covers it.
Charge controllers can be slightly different from the one shown, but all have the same basic connections – usually an input pair of wires (from the solar panel), battery pair of wires, and load (ie items that need power) pair of wires.
The most important thing with 12V DC solar is ensuring you always maintain the correct polarity, i.e. that positive wires go to positive connectors and so on.
