This is a portable battery pack that is charged using solar energy. It features a built-in light and USB sockets for phone charging. It can be used when camping, living off-grid or during power cuts.
This pack uses a 7 Ah sealed Lead Acid battery which has an energy capacity of 42 Watt Hours - allowing the battery only to discharge to 50% of its rated capacity. Typically this could charge a mobile phone 3 times or keep a 5 Watt LED light continuously on for 8 hours.
A 10 Watt solar panel would comfortable recharge this battery in about 8 hours ie 2 summer days or 3 to 4 winter days. A 20 Watt panel would recharge the battery in half that time.
Solar Power Pack - how to connect the devices together
Solar Panel
These come in various power ratings from tens of Watt right up to hundreds of Watt. For this project we will mainly be using 10 Watt or 20 Watt panels. The panels typically output more than 12 V and are designed to charge a 12 V battery.
Always take care to connect the solar panels the right way round. The positive side is usually coloured red. Here are a couple of links - but shop around for your panel.
20 Watt panel (about £30)
Battery
Batteries come in different sizes and technologies. For this project we will be using 12 V sealed lead-acid batteries of 7 Ah capacity. This has a (7 x 12) 84 Watt hour capacity. The recommendation is only to use 50% of this before recharging. That gives us 42 Watt hours - enough to run a 5 Watt led light for 8 hours continuously or charge a couple of phone. The 10 Watt solar panel will recharge this battery in about 4 hours if placed in full sunlight.
Batteries need handling with care as they have a lot of stored energy. The one shown here has a 10 Amp fuse to protect against shorting.
7 Ah 12V Sealed Lead Acid Battery (about £20)
Charge Controller
The left 2 wires connect to the solar panel, the middle 2 to the battery and the right 2 to the load. Always connect to the battery first. Never connect a solar charge controller to a solar panel before connecting to the battery.
12/24V, 30A Solar Charge Controller with Dual USB Port (about £10)
This is the type of 12 V low-power LED light that can be plugged into the charge controller output directly.
12V LED Lamp (about £10)
It is always useful to know how the battery is charging or how much power is being taken by the load. A Watt Meter is an easy way of measuring this.
Wiring the components together
This shows the solar pack all wired up.
Step 1: Connect the battery with fuse, to the charge controller. The display should light up and the battery voltage will appear on the top right.
In-line 10 Amp fuse holder
10 Amp 20mm glass fuse
Battery
Batteries come in different sizes and technologies. For this project we will be using 12 V sealed lead-acid batteries of 7 Ah capacity. This has a (7 x 12) 84 Watt hour capacity. The recommendation is only to use 50% of this before recharging. That gives us 42 Watt hours - enough to run a 5 Watt led light for 8 hours continuously or charge a couple of phone. The 10 Watt solar panel will recharge this battery in about 4 hours if placed in full sunlight.
Batteries need handling with care as they have a lot of stored energy. The one shown here has a 10 Amp fuse to protect against shorting.
7 Ah 12V Sealed Lead Acid Battery (about £20)
Charge Controller
The life of batteries can be greatly extended if one takes care when charging and discharging them. A charge controller is a way of connecting the solar panel to the battery to prevent it over-charging. It also connects the load to the battery to avoid flattening the battery.
The charge controller below can be bought as a 10, 20 or 30 Amp versions. Just multiply by 12 to see what the maximum size of solar panel that can be connected. For example, the 10 Amp version can be used for solar panels of up to 120 Watts output.
The left 2 wires connect to the solar panel, the middle 2 to the battery and the right 2 to the load. Always connect to the battery first. Never connect a solar charge controller to a solar panel before connecting to the battery.
12/24V, 30A Solar Charge Controller with Dual USB Port (about £10)
12 V Lamp
This is the type of 12 V low-power LED light that can be plugged into the charge controller output directly.
12V LED Lamp (about £10)
Watt Meter
It is always useful to know how the battery is charging or how much power is being taken by the load. A Watt Meter is an easy way of measuring this.
12V Watt Meter
Wiring the components together
This shows the solar pack all wired up.
Step 1: Connect the battery with fuse, to the charge controller. The display should light up and the battery voltage will appear on the top right.
Step 2: The Solar Panel is connected through the Watt Meter to the Charge Controller. Once the panel is moved into the sun the Meter will display charging current, voltage and power.
Step 3: Connect a LED light and see it working.
Step 4: Move the Watt Meter between the Charge Controller and the LED light to see how much current and power it takes.
Other Components
Cable
As the battery is fused with a 10 Amp glass fuse, this is the maximum current that can flow in the cables. So all cables used in the pack needs to be capable of taking at least 20 amps.
12V 30Amp 2.5mm cable
Connectors
Fuse holder
In-line 10 Amp fuse holder
Fuse
10 Amp 20mm glass fuse
No comments:
Post a Comment