The solar charge controller (for example: RENOGY 40 AMP MPPT CHARGE CONTROLLER )provides one of the missing links for small off-grid solar setups, and could be the key to more build-your-own systems.
When it comes to keeping our smaller devices powered up while off the grid, such as smartphones and other portable electronics, there are quite a few choices for small-scale solar chargers and portable battery banks, many of which are affordable and reliable.
However, for charging anything larger than a tablet or small laptop, the options on the market get rapidly fewer and the prices seem to get much higher, part of which comes from the addition to some systems of an inverter (which converts the battery's DC current to the AC required by most home appliances), as well as the much larger battery required to power those AC devices. And while plugging a standard AC plug into a battery bank is convenient, and a necessary feature in a home solar system, it's not a requirement if you're only looking to provide DC power for camping or as part of an emergency preparedness kit, and homemade battery banks can be built for a fraction of the cost of off-the-shelf solutions.
That's where this next gadget comes in. It could make build-your-own portable solar solutions much simpler and more affordable than other purpose-built options, by acting as the brain between the solar panels and a battery bank. Bear with me now, because while the idea of a compact solar charge controller isn't nearly as sexy as the image of the solar panels feeding into it, this little 'black box' looks to be a great entry-level DIY solar component.
With both plug-and-play functionality and the ability to accept custom charging configurations, this little gadget aims to enable efficient solar charging of a variety of build-your-own battery banks, ranging from a standard deep cycle lead-acid battery to various lithium chemistry batteries. The Inti C14 claims to be "the smartest, most powerful solar charge controller for its size," capable of handling up to 400W of input and an output of up to 30V, and while simple to use, it also has enough features to allow users to get pretty geeky about their solar charging and battery setup.
Here's the video pitch for Inti C14's usefulness for portable off-grid power setups:
One of the comparisons made by Razvan (Raz) Turiac, the creator of Inti C14, is the cost of a homemade battery bank setup compared to a leading purpose-built solar "generator," in this case the Goal Zero Yeti 1250. At the heart of the Yeti power bank, which retails for about $1250, is a 12V 100Ah sealed lead-acid battery, whereas a homemade version built by Raz, which also uses a lead-acid 100Ah battery, can cost just a fraction of that, in part by not including an inverter, and in part by using a common $100 deep cycle battery. According to Raz, not having an inverter isn't really a loss for a homebuilt system like his, as many common off-grid devices are designed to use DC current anyway (such as his example of a DC refrigerator), and AC appliances with higher power draws aren't really practical to run on smaller systems like this.
For the system built by Raz, he used 4 semi-flexible 50W solar panels, which makes for a lighter and smaller portable solar system, but it's certainly possible to use smaller wattage panels (or even just a single panel) to generate the electricity to charge mobile devices and/or the battery bank if you don't need to power an appliance like a refrigerator. This flexibility in configuration is another reason why building your own system can be a more affordable option, as both the solar panels and the battery bank can be sized according to your specific power needs.
Obviously, it's not fair to directly compare build-your-own systems with battery banks like the Yeti, as there are a host of features on purpose-built power banks that won't be included on a homemade version, but for those looking for a more affordable option, the Inti C14 can play an integral role in making sure the solar (or grid input) charging function is efficient. It's not the only portable solar charge controller on the market, by any means, but it does look to be a good option for setting up smaller (up to 400W) systems that are meant to be portable and simple to configure.
A few other highlights:
Can handle a solar input of up to 400W
Can take from a variety of sources, ranging from solar panels to an auto DC output to grid power via an AC adapter
Compatible with "any battery chemistry" with voltages up to 30V
Can be monitored and configured by either USB port or via Bluetooth connection
Can be used as a battery analyzer / data logger
Uses MPPT (Maximum Power Point Tracking) for efficient solar charging
Has standard MC4 connectors for ease of connection to solar panels
Weighs just over half a pound
The Inti C14, from Thornwave, is in the fully functional prototype stage, and Raz has turned to Indiegogo to crowdfund the production of at least the first 1000 units and to get both the firmware and the software to production quality by the summer of 2017. Backers of the campaign can get their hands on one of the solar charge controllers for pledges of at least $99 (said to be 44% off the eventual retail price). Find out more at Thornwave.