DC Load

This is your canvas. Provided you keep within the bounds of the system design window, you can run just about anything you like.

Security cameras, modems, dataloggers & sensors, PoE injectors, gateways, rebroadcast stations, WiFi hotspots.

“The world is your oyster!"

The No. 1 reason why a solar/battery system fails is because the load being powered was not properly understood & matched to the system design.

When planning your solar/battery system you should always think of the load as the foundation of the design. If your foundation is not firmly established, the structure you put on top of it will collapse.

There are a few key points that should always be considered in order to avoid the most common pitfalls.

1) Have an accurate understanding of how much power each device needs, and how it behaves at different operation modes.

E.g. many communications devices will have different power needs in standby/ receive mode compared to active/transmit mode. It is essential to understand what the power requirements are in the different operating modes AND how much time the device will spend in each mode.

For example, you have a device that needs 5W in receive mode but 25W in transmit mode. If it’s daily duty cycle is 80% standby and 20% active, how many Wh does it use in a day? Flip that to 20% standby and 80% active, how many Wh of energy does it need then?

[(5W x 24hrs x 80%) + (25W x 24hrs x 20%) = 96 + 120 = 216Wh]
[(5W x 24hrs x 20%) + (25W x 24hrs x 80%) = 24 + 480 = 504Wh]

So the SAME DEVICE has over TWICE the impact on the system design just by changing it’s usage cycle. Properly understanding the power needs and duty cycle in the worst case operating scenario will ensure that the solar/battery power system can remain operational at all times.

2) Consider any seasonal changes
Some systems will have the same usage behaviour all year round. But others will vary significantly with the seasons.
E.g. some sites will need to ensure a controlled environment for their equipment. While Summer Air Conditioning demand can be significant, it may also be largely negated by the longer days and increased solar availability of the season. On the other hand, Winter heading demand can represent an enormous portion of the Winter load requirement. That increased demand is further exacerbated by the lower solar availability of the season. Always consider the worst case scenario when designing for seasonal loads.

3) Don’t forget the accessory devices
A lot of devices are not factored into the load design as they’re considered minor. But when you add up several minor-but-ignored devices, particularly ones that have a 24/7 active or even standby power drain, you quickly use up any reserves that may have been designed into the system.

4) Always design in a reserve
To ensure system reliability you always need to build in a reserve. This should be ON TOP OF any buffer included in the design for future expansion of the site or upgrade of the equipment capabilities (e.g. adding a second camera to a security monitoring point).