Solar Panel Charging

Basics about solar panel battery charging.

Panels

Monocrystalline panels are regarded as being the most efficient panel technology. Second to Polycrystalline panels.

Common configurations of individual panels:

• 100W - common
• 120W
• 150W - common
• 160W

Arrays are usually build by parallel installation of multiple of the same panel type, e.g. 10x150W panels is a 1500W or 1.5kW array.

Some cheap flexible panels:

• 100W 18V Mono panel - 137USD

Solar controllers

There are two kinds of controllers; MPPT and PWM charging mode, with the former being the preferred one on larger (>50W) setups.

A reasonable decent solar controller starts at 50USD, for a 10 to 30A 12V setup. A 30A controller can handle up to 30 x 12 = 360W of solar panels connected to the input.

• Solar controller 30A 12V - 44USD

Batteries

Using regular 12V or 24V batteries makes it simple to get locally.

Building solar panels

It is possible to build a large solar panel from scratch. You only need to get the individual parts, which is really not that much or hard to put together.

• Solar Cell - photovoltaic module, converts sunlight to electric current, provides approx. 0.5V
• Solar Tabbing Wire - connects modules into strings - multiple cells connected together, e.g. 9 cells provides 4.5V (0.5V x 9)
• Bus Wire - connects the strings into an panel, e.g. 4 strings provides 18V (4.5V x 4)
• Flux Pen - makes it easier to solder the tabbing and bus wire
• Backing Sheet - works as an insulator and protects the back of the panel, usually a multilayer laminate
• Junction Box - connects the two bus ends to screw terminals
• Solar Cable - makes it easier to connect multiple panels together, e.g. in series (higher voltage) or parallel (more current)