[Commotion-discuss] Remote site, solar-battery data logger.

[Ben West]

I asked this of a friend of mine who does rooftop solar installations for
large institutional clients.  The cheapest stand-alone datalogger with IP
access that he knew of would ring in at the $350 range, i.e. half the cost
of the X-320 product, but still rather pricey.

He did agree that using an inexpensive embedded computer like an rPI or
Arduino would be a better option for for a rooftop / mesh wifi rig,
especially if one of the radios or ethernet switches has a spare RJ45 jack
or even an USB jack. The USB jack could be interesting, in that it could
let you use an inexpensive GPIO breakout board to provide the screw
terminals and voltage translation for monitoring battery health and charger
controller activity.  Maybe a USB to GPIO breakout like this:
http://www.dx.com/p/crius-ftdi-basic-breakout-5v-usb-to-ttl-6-pin-module-for-mwc-multiwii-lite-se-228307#.U3j8eI_XPPU

The web UI and monitoring logic could run directly on the USB host.

Indeed, Ubiquiti Rocket radios do have a USB jack although I'm uncertain of
their support in OpenWRT.  The Rockets do have rather generous 64MB RAM,
tho.



On Tue, May 13, 2014 at 9:53 AM, Andy Gunn
<andygunn at opentechinstitute.org>wrote:

> Hi Jared - just to follow up on Dan's message, I think you will probably
> have to use a few products to accomplish this task, or plan on spending
> quite a bit for a higher-end charge controller.
>
> Just a note: I'm not a solar expert, but I did do a stint as an
> electrician, working on solar installations along with the usual
> residential stuff. I am more of an expert on remote monitoring,
> instrumentation and control from my time working in radio, where remote
> control of distant transmitter sites is a must.
>
> That said, I was able to find a charge controller from a company I have
> actually heard of that has Ethernet access and some semblance of control
> over the web. Note: I have not used this controller before, so I can't
> speak to it's features:
>
> http://www.midnitesolar.com/productPhoto.php?product_ID=331&productCatName=Charge%20Controllers%20-%20Classics&productCat_ID=21&sortOrder=5&act=p
>
> Obviously, it's not cheap, so that doesn't fit your low cost need. My
> suggestion is to use an off-the-shelf charge controller, and combine it
> with a remote monitoring sensor or remote control unit that you can
> program to monitor voltages, temperatures and use internal relays to
> reboot or disconnect equipment.
>
> Some examples of lower cost PWM charge controllers are here:
> http://www.solar-electric.com/stpwmchco.html
> (Though PWM are not the most efficient charge controllers, they are
> lower cost)
>
> A company called Control By Web has a series of very good remote control
> units with web interfaces:
> http://www.controlbyweb.com/products.html
>
> While they are not exactly cheap, they are robust and some have multiple
> features. They are also small, DIN rail mountable, and low power. My
> recommendation is the X-320, though it might be overkill:
> http://www.controlbyweb.com/x320/
>
> If you have more time on yours hands, something like an Arduino or
> Raspberry Pi can be set up to take in voltages or sensor data on the
> analog inputs, control external relays, and is fully programmable. I'm
> not an expert with those, so I am only speculating, but I think would be
> able to serve your purpose very well.
>
> Sorry I don't have a magic bullet, but I'm hoping someone out there is
> working on one!
> -A
>
>
> On 05/13/2014 09:54 AM, Dan Staples wrote:
> > That sounds like a tall order :)
> >
> > I've had little experience with solar powered tech, but from what I have
> > worked with and seen, there isn't any sort of all-in-one package like
> > the kind of thing you describe. Folks I've seen that have rigged up
> > solar panels and batteries to routers and the like have had pretty DIY
> > setups.
> >
> > One person who I would suggest talking to is Danny Iland
> > (http://www.dannyiland.com/). He does solar-powered wifi router stuff,
> > which he demoed at last year's Int'l Summit for Community Wireless
> Networks.
> >
> > -Dan
> >
> > On 05/08/2014 01:23 AM, Jared Hoy wrote:
> >> I'm thinking about setting up some high vantage point routers that are
> >> operated by a solar panel and some small SLA or lithium batteries. I
> >> have been looking around for low cost solar chargers that incorporate
> >> "smart charging" capabilities combined with data logging and
> >> network-ability.
> >>
> >> Does anyone know of any small, low cost, weatherproof solar chargers
> >> that can charge a single sealed lead acid battery, lithium ion, or
> >> similar battery? Something that also incorporates a small data logging
> >> memory that can be accessed and visualized remotely over a network
> >> connection? Something that is HTML so it can be viewed in a webpage on
> >> any platform? Maybe even email alerts to alert when the system requires
> >> maintenance?
> >>
> >> Like I said, the routers would be located in difficult to reach and
> >> remote locations and should be stand alone and off the grid. I need a
> >> way to keep an eye on the system without being physically present unless
> >> absolutely necessary. Ideally the only malfunction that should occur
> >> would be a failing battery and would need to be continuously monitored
> >> for the continued safety and security of the community.
> >>
> >> I'd like to avoid building my own chargers unless there is no
> >> commercially viable and inexpensive solution.
> >>
> >> Any comments, thoughts, suggestions?
> >>
> >> thanks,
> >> Jared
>
> --
> Andy Gunn, Field Engineer
> Open Technology Institute, New America Foundation
> andygunn at opentechinstitute.org | 202-596-3484
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-- 
Ben West
http://gowasabi.net
ben at gowasabi.net
314-246-9434
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