The Digital Agency for International Development

Solar Diaries - Day 9 - Darkness

By Alan Jackson on 02 October 2010

load disconnectedStarted the day with a cloudy sky and just over 12 volts. Not wanting to push my luck I only used the 24" monitor for about half the day. I turned it on when I was remote-pairing with Hamish in the office who was using a 1280x1024 screen, which is bigger than my laptop's screen.

I got through the day fine and with a full laptop battery. But by the end of the normal work day, around 6pm, especially on a cloudy day, the lack of any lights is becoming a bit difficult. The nights are drawing in and trying to read a monitor, even one on the dim "eco" setting, in a dark room is a strain on the eyes.

Rather, I should say I got through the normal 8 hour working day fine. 8 hours use a day is what I've been planning the solar power system around - however today has reminded me that 8 hours isn't always what happens. For much of the evening I've been doing work-related reading, running down the laptop's battery. Then I started researching into low power 12 Volt LED lights. LEDs can be very intolerant of variable voltages and get damaged if the voltage goes above their rating. With some searching I've found some LED "bulbs" that have voltage regulators built in so they take a range from 8 - 30 Volts and even claim to take AC or DC. I was half way through ordering a 3 Watt and 6 Watt bulb when the laptop battery screamed for help.

I hooked lappy back up to the solar battery which let me finish my order. Not long after that the solar controller shut the battery down. This is the second time now that the controller has shut down the battery. It's the weekend and I've got Monday and Tuesday off work so I've got 4 days to charge the battery back up again... although I'll be at Barcamp Brighton this weekend. Maybe I should take the panel and the 33kg battery with me... or maybe not.

End of day battery voltage: 11.8V