Solar Power Off-Grid Systems.
Updated: Jan 27, 2022
Powering devices via a Solar Power System can be a fantastic off-grid solution. But in the UK we are not always blessed with sunshine. So how can you be sure you system will keep your devices online?
Matching a battery to solar panels is key to ensuring that you system is efficient, maximising the solar generated power with the capacity and technology of the battery alongside the power usage of the connected devices..
So what are the key elements of the solar power system?
In the simplest terms the key elements are a solar panel, a charge controller and a battery.
The solar panel absorbs the sunlight and feeds it as electrical current to the charge controller. The charge controller monitors and recharges the battery power level and monitors the load output that powers your devices.
However the load output from a 12V battery is DC. The majority of IoT devices run on 240v AC power. To delivery AC 240v power to your devices you will need to feed the power from the charge controller through a power inverter. Again matching the power converter to your battery and devices is key to ensuring your system operates efficiently.
There are some simple calculations you can do to understand the power requirements of your device v’s the battery capacity and solar feed.
Let’s start with the battery you are installing. We need to know the watt hours of the battery in order to match It to the solar panel and device power consumption. Let’s use a 12v 100Ah battery for the example. To calculate the watt hours we multiply the voltage by the Ah’s
12v x 100Ah = 1200 watt hours
Next we need to take in to consideration the number of daylight hours we can anticipate. In the UK it is always better to assume the worst case scenario to ensure you system remains charged. sunsettimes.co.uk provides useful information on the sunlight hours per day in the UK. If we take January as our example we can use the assumption that we will have 7.5hrs on sunlight per day. However cloudy and rainy days significantly reduce the absorption of energy the solar panels can deliver.. To ensure our system is effective it would be wise to reduce this number of sunlight hours to allow for the grey British winters. For this example we will reduce the daylight hours to 5. To calculate what solar panel size we will need we divide the watt hours by the sunlight hours
1200 watt hours / 5 = 200 watts
So to keep our 100Ah battery charged in the UK in January we will need a 200 watt solar panel as a minimum.
The final consideration is the power consumption of our devices. BatteryStuff.com provides a really helpful calculator to work this out. If we use the Move Solutions Gateway as the device we are powering, it has a typical power consumption of 12 watts and operates on a PoE (Power over Ethernet) feed from a 12v DC power jack. The calculator needs an amperage which we can calculate by dividing the watts by the volts.
12 watts hours / 12 volts = 1 amperage
Assuming you want your system to stay online 24hrs a day, using the BatteryStuff.com calculator, you will need a battery with 46Ah minimum to keep your system online. As the grey British weather is an almost certain, it would be recommended that you double this as a minimum to ensure your system is capable of keeping your battery recharged.
We take our solar to battery calculations and our device power consumption to battery calculations, and in this instance it would be advisable to install a system to the minimum following specification.
Battery - 100Ah (assuming a sealed lead acid battery)
Solar Panel - 200w
Dyna-mo Instruments use these calculations to ensure our power systems can keep your devices online. We offer a 400w solar solution for installations where it is critical that the system stays online no matter how overcast the british weather is.
It is equally important to install solar panels in the optimum position. Our solar panel mounting brackets ensure that the solar panels are at a 45°, which maximises their sunlight absorption. Solar panels need to face south with as little obstruction to the sunlight as possible. It is important to remember that in winter months the sun is much lower in the sky. The more hours the solar panel is in direct sunlight the greater the power feed is to your battery. You can find our Power Systems using this link
If you have specific power requirements for your system installation we can develop bespoke solutions including battery, solar, wind, hydro and combination off-grid power.
We develop integrated solutions to solve your installation challenges so please get in touch if you have a specific need or question for us to solve.
m 07533 970209