Britain's highest off-grid webcams - Work party Wednesday 16th December.
Our webcam set-up is unique (winterhighland webcams on Lowther Hill ), it is not just at a high elevation, but it is entirely off-grid, communicating to the outside world over a mobile network and without a connection to mains electricity.
Over the last few weeks, image output has been erratic and volunteers have made countless visits to implement advice to check and adjust the set-up such as recharging batteries off the hill to ensure battery health, fitting lower impedance wiring, checking for dry connections, changing timing cycles to reduce power load, making sure there are no shadows falling onto the solar panels, removing and refitting all electronic components, assessing mobile signal strength, observing that the computer OS successfully boots and communicates with all USB devices, and ensuring that no moisture has penetrated internal or external cabling. It became clear that despite everything appearing to be in order, we are only able to get imagery from the hill at the immediate time of the visit with the system always failing shortly afterwards once the battery capacity becomes depleted again.
So on 16th December (a typical weather day), Alan Mackay from Winterhighland who has already invested many days of his freely given time with us, spent the afternoon with Ross Dolder looking at the set-up and potential remedial options. They took a portable battery and electrical testing equipment, rechecked the Raspberry Pi computer, the charge controller, the timer, the USB power adapter, the solar panels and the cameras themselves and Alan Mackay determined and agreed that all components are indeed working as they should. A light meter was used to measure the insolation values outside the hut, just after midday and again at 3 pm showing that this value at the brightest time of the day was around 150 lux, falling to less than 100 lux before sunset. To put that into perspective, this corresponds to the approximate light value inside an office building hallway and under these conditions, the 2 x 80 watt solar panel array are observed to be outputting less than 0.1 amperes. For comparison, when Ross Dolder made a specific visit timed to coincide with a rare brighter morning just three weeks ago, in the direct watery sunshine, the solar panels were briefly seen to be generating between 3 and 4 amperes (in the summer months, he has observed as much as 11 to 12 amps). The power load of the webcams, their heated enclosure, the Raspberry Pi computer, charge controller, timer, USB power converter, and the combined internal resistance of all componentry varies between 0.4A and up to 1A depending on temperature.
In summary, if Lowther Hill had been blessed with even just a few days of decent sunshine during November and the first half of December, with the system optimised to use as little power as possible, we would likely have had enough capacity to continually power the webcams even accounting for the increased power draw in the winter months (webcam heated enclosure) and lower battery capacity at low temperatures. However, after the dullest November in 86 years ( Scottish Daily Record article ), and with this December following the same trend, the average power generated is insufficient to maintain battery capacity and it is estimated that under current conditions we would really need around 10 x more solar panel capacity just to balance the input/output of the system. Alan and Ross also considered supplemental power sources such as a fit-for-purpose small wind turbine rated to 100 mph gusts and to generate power (not shut down) at the high average wind speeds on Lowther Hill, and alternative 'hands-off' system such as bio-ethanol fuel cells but these options are prohibitively expensive for the ski club just now.
Alan Mackay made further tweaks to the load cycle to optimise the power usage and then gave us the much better news that with the charge protected components already installed, it will be quite safe to use the alternator from the ski tow engine to charge the system and it is expected that the deep cycle batteries could be topped full in a very short time, powering the system for a week or so until the next time that the engine is running. Happily, the times when the engine will be run coincide with the months of least solar generation. We will shortly be fitting a diesel exhaust vent and safety brake inside the engine shed, and will soon be able to safely recharge the webcam system. Between April and October when the ski tow engine is not expected to be run so regularly, the solar panels will take over again.
To conclude, while the club cannot currently afford to pay for additional capacity to top up the batteries during the dullest months, we may soon have a work-around to deliver regular webcam images again and when we're sure we've got enough power, we will fit the weather station too. Meantime of course, we would be overjoyed if someone, somewhere found us some ethanol fuel cells or a suitable wind turbine going spare that we could fit at our engine hut !
And watch this space for news of another Lowther Hills Ski Club winterhighland webcam coming soon ;-)