Introduction: Solar Portable 12v Charger

About: I'm retired so now I work for my wife.

Reading many of the
builds on this site has inspired me to utilise some bits and pieces bought for other projects but never used i.e. a solar cell and solar regulator to make a 12v portable battery supply. While my build is not a new concept it is designed around my needs and the build is always open for changes as I learn more about this subject.

I don't intend on listing every nut and bolt used or have a mini tutorial on how to drill holes as I think everything is self evident from the photographs but I am always open to questions.

Main parts are

12V 10W Solar Cell

Solar Regulator

12V 7AH Battery

“Really Useful” 245 x 180 x 160mm 3L Box

Waterproof car sockets

2.5mm Power plug and socket

Step 1:

I've positioned the 2
waterproof sockets on the right and the power connection from the solar cell to the left. The position of the sockets means I will be able to use some internal space to store cables and spare fuses etc. I have also reinforced the socket to box connection with epoxy resin as I didn't have a hole cutter exactly the right size.

Step 2:

The wiring comes from
the solar cell on the left and into the solar regulator. The middle wires are fitted with plug and socket type connectors. The right hand wires go to the top outlet socket via an inline fuse holder (5amp).

During normal usage the internal battery will be online but when I need to connect to the car battery I disconnect the socket on the 7ah battery supply and connect the plug to the bottom socket socket. A connection to the car battery is then made with a cable fitted with 2 car cigarette lighter plugs connected to the bottom socket. In this configuration I can trickle charge the car battery and use a voltage inverter safely as the input and output voltages are controlled through the regulator.

Step 3:

I fitted the socket
part of the connector to the battery side as this gives better protection against accidental short circuiting and the battery terminals have been taped up for the same reason. I would have also liked to have made a better shelf to to place the regulator on but that will have to wait for another day.

Step 4: Circuit

I'm not very skilled in
this department but here's a diagram for the circuit.

PV1&2 Solar cell

A to F Solar regulator

V1 internal 12v battery

V2 Car 12v battery

F1 Fuse

OUT 1&2 12v out socket

OUT 3&4 12v car in/out socket

Green Electronics Contest 2016

Second Prize in the
Green Electronics Contest 2016