50w Solar Panel Setup to Charge Phones Batteries

Jesus Luzon edited this page Oct 5, 2017 · 4 revisions

IMPORTANT: While this is a simple and easy to implement setup, this is an electric system and you have to be careful. Proper safety measures and caution should be taken to avoid a potential fire. If you connect anything and start to feel any wire get hot or smell burning, disconnect immediately and ask for help. Make sure it is kept away from children as they might get hurt or cause damage to the system that could cause a fire or worse.

I’ve been trying to get a Solar Setup running in order to help my family be able to charge their devices throughout the crisis after Maria. The goal here was to be able to build a system that is accessible to people in PR leveraging the resources left available after the hurricane. Because of this I have sourced all parts from Amazon in order to make it simple for anyone trying to do this themselves to receive at their doorstep as USPS starts operating again. The only parts you will have to source locally are the battery and some tools. Any car battery can be used with the proper precautions being taken.

A solar setup is a lot simpler than I had expected and basically has 4 parts which are all fairly straightforward to work with.

  1. Solar Panel - Converts sunlight into electricity
  2. Charge Controller - Takes the energy from the solar panel and charges the battery with it. Also controls the load being taken from the battery so the battery isn’t overdischarged and damaged.
  3. Battery Bank - This can be a range of things but a single car battery for a basic setup will work.
  4. Power Source (Power Inverter or Car Charger) - This is how we will consume the solar power. The power inverter will allow us to run 110V AC devices (regular things you plug on the wall) but you can also opt for using a cigarette lighter adapter and a car charger.

For the solar panel and charge controller Renogy has a decently priced bundle for a 50W kit. This kit includes:

  1. 50 Watt Solar Panel
  2. 10 Ampere Charge Controller
  3. 1 pair of MC4 plugs with 20ft cable (to connect Solar Panel to Charge Controller)
  4. 1 pair of 8ft tray cables (to connect Battery to Charge Controller)
  5. 4 brackets with bolts nuts and washers (for mounting the solar panel) This allows for a pretty flexible install since the cables are fairly long.

Now we’re missing 2 things, a battery and an inverter or DC Cigarette lighter slot (we’ll do both!)

Any 12v car battery should work but their rating for Ah (Ampere hours) define how much charge they can store. By multiplying the Voltage by the Ah, we can get the Watts hour that our battery provides. For example, a 12v battery that can sustain a 100 Ah charge will give us 1200 Wh. These batteries can be damaged if discharged over 50% so we will only assume we have 600 Wh available. What does that mean? That we can power a 600 Watt device for an hour, a 300 watt device for 2 hours, a 100 watt device for 6 hours, etc. I will not be able to link to any battery on Amazon here because most don't ship to the island but these are easy to find at any store that sells car batteries.

Now lastly we need a way to use the power from the solar panels and/or from the battery. Since this is a simple setup meant mostly for charging phones and such, we can add a 12v cigarette lighter to plug in an inverter or a car charger for a cellphone. This car lighter adapter plugs directly to the charge controller under Load and allows the charge controller to cut power to the device if the battery levels get too low. This is to prevent the battery from being damaged by over discharge. I will recommend a small inverter because it gives people more flexibility since not everyone owns car chargers for each of their devices.

Now we can plug in an inverter such as this one which would allow us to plug 2 USB devices and 2 AC devices at the same time. Note that this inverter can only handle up to 150W of power at a time but this is enough to charge most phones, laptops, portable power banks and other small devices. NOTE: IF THE BATTERY IS AN UNSEALED BATTERY KEEP IN A VENTILATED AREA. SEE THE VENTILATION SUBSECTION HERE FOR MORE INFO

After obtaining all of the basic parts for the system they will need to be assembled and could require some extra parts and some tools that are easily accessible for most people but should be confirmed to be available. Make sure you have access to:

  1. A small flathead screwdriver - This is used to attach the wires to the charge controller and one's that too big will not fit. I used the biggest flathead from a precision screwdriver set just fine, but other screwdrivers with a thin flathead should also work.
  2. Battery Terminals - You will need battery terminals such as these to attach the wire from the charge controller to the battery itself. It is very likely you can buy these where you buy your battery or any automobile parts store should have some in stock.
  3. Adjustable Wrench or Ratchet Set - You would only need these to be able to attach the charge controller cable to the battery and tighten it.

Here's a diagram made by @ecrespomit that illustrates that the wiring looks like. image

Altogether this setup costs at the time of this writing $138.21 plus whatever the battery, terminals and tools you have to end up buying cost. Given the scarcity of AA, AAA and D batteries on the island right now and how expensive they are this setup could pay for itself if used to charge rechargeable batteries until power comes back. This setup can be scaled up to supply more power with a few upgrades but cost will also increase. One of the better things you can do with this setup is recharge your portable power banks or rechargeable batteries to be able to power flashlights, lamps and/or fans at night.

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