I spent the last couple days tinkering with the Solar laptop Station. Yesterday I got to run the laptop with it for a bit. Those of you that have been following in some of the Tiny House Forums /Blogs know that I have been working on this idea for the last few weeks. I had picked up some 10 Watt Solar panels during the summer to set up some testing rigs for the I-pod / Computer speaker “stereo”, and recently picked up a few more parts to make this work. My original plan had a custom made wood box to house the solar panel / battery etc…I ditched that Idea, It was bit bulky and heavy. I found some Aluminum briefcases on e-bay that were the right size for my project. Not only are they lighter and more user friendly they look pretty tech. I set it up with the basic idea of a 10 watt panel feeding into a 2.2 A/Hr battery. The battery feeds a standard cigarette socket, since most people have many “car” adapters to run things (Cell phone, laptop, portable DVD, etc.) this prototype could supply power for many things other than a laptop. To aide in monitoring I wired in a few switches that allow me to isolate the solar panel from the battery and the battery from the Solar Panel. By reading voltage at the auxiliary banana plug ports. I can easily see how much power is being generated by the panel and what the current state of charge is of the battery.
The Solar panel has a small channel on the aluminum frame that fits perfectly into the edge of the case. A couple of custom mini bungee cords and the panel is held nicely in the case at a great angle collecting sunshine. Inside the case there is enough room for an additional or a larger battery. I have some “pick and pluck” foam coming in soon that I will add to the case to secure a spot for the net-book. The panel will fit into the lid of the case and is held in place by a nylon strap. It only takes a few seconds to set the panel and attach the bungees. I will add a Morningstar Sunguard Charge Controller as soon as I get it in. The style of SLA (Sealed Lead Acid) battery I’m using prefers a charge voltage of about 14 volts. The charge controller will ensure this is the case. This panel can generate over 20 volts in bright sun and even puts out 18 or better just sitting by the window. If I continued to use these higher charge voltages the batteries would not perform as well.
I”ll do some more testing on charge and discharge rates over the next week or so to test the capacity of the 2.2 AH battery. The case that is pictured here is the thinnest I got. I also have two deeper cases that I will be building up as well. The bigger cases could easily hold the 10 AH battery I got, or one that’s bigger still. They will also have room for a small inverter to make a complete portable “power station”. My goal is to have something that is still very portable, yet powerful enough to supply the needs of regular use. I have seen some “ready made” systems, but they have tiny panels that must take forever to charge with….and some are quite pricey too. I’m hoping to build these for $300 to $350 for a few select clients / friends.
Here are some links to some ready made units that I found online, one with some storage capacity (very small compared to my 2.2 ah) and one that just has a panel and cigarette socket.