Summertime and the Livin’ is Easy

Living in one of the most beautiful cities in the world, we’re constantly tantalized by the sunshine to work outside.  So we built a mobile office setup that allows us to work anywhere we want to. The mobile office is solar-powered and packs into one (midsize) car, and can support about 10 laptops charging plus a 4g wifi connection.  Want to cowork with us this summer? Check in on the iPhone App to find out where we’re at!

Harnessing the Sun

For those of you who are more technically inclined here’s an in-depth explanation of how our solar system works.

First, the battery is connected between the charge controller and the inverter to allow the charge controller to start up. Next, the two panels are connected into the system on the other side of the charge controller, completing the circuit. The solar panels are PowerFlex 6 Panels from Global Solar, each rated at 225-300W at around 65V. Connected in series, they hypothetically produce about 600W at 130V. These panels essentially both charge the battery and push power into the inverter, which converts the DC source from the solar panels into an AC output identical to what you can get out of your walls at home.  A schematic of the system is visible below:

Try, Try Again

The first iteration of the system involved a lot of stray wires and pieces which were loosely held together. Although this was satisfactory for testing and proof of concept, it made the system very difficult to transport and also created a lot of instabilities. As a solution to this problem I decided to mount the inverter and charge controller onto a piece of plywood with handles for easy transport. This also has the advantage of fixing the distance between these two components, eliminates the possibility of a wire being yanked out by moving one or the other, and allows for permanent installation of the alligator clips into the inverter. A picture of the new setup is visible below; it is relatively small and mounted on a 20”x30” piece of plywood.

Batteries Not Included

The last piece of the system to be modified was the battery. Originally the system was run off of a 12V marine deep cycle, lead acid battery. For this type of battery, it is unsafe to completely discharge and recharge it and it can only absorb energy to charge at about 75% efficiency. To replace this piece of the system we have decided on a lithium ion battery which will be able to endure many more charging/unloading cycles and also absorb the solar energy at about 97% efficiency. In addition, it is a lot lighter at just 14 pounds and will make the transport/assembly of the system all that much easier. Stay tuned for more updates on the solar pop-up office as we try it out in various locations around the city!