Last weekend, mid-July, marked the 10-week point of running my phone and my watch off solar power alone. I figure if we're going to turn the British summer into a molten hellpot through global warming, I might as well benefit from it. Here are some notes on how I've done it (not complicated) and thoughts on what I've picked up along the way (not profound).
I did also run for about 3 months on solar a few years ago, with a different setup, but the gist was the same. It's good to know not too much has changed compared to back then.
Broadly speaking, there are three main things that I think are useful when moving to solar power at this level: hardware, including solar cells (natch), an understanding of battery use, and the right mindset.
Bear in mind that this is a fairly amateur approach to solar power, intended to run USB devices only. More nomadic people, such as those with camper vans or house boats, have bigger setups, which I haven't looked into yet. My main aim is to be portable with just a rucksack, if I want to be, and to power a bare minimum.
So here we go...
[ Note: Forgot to add in my routine here, will update this post later to include thoughts, but generally I just charge up when there's good Sun ;-) ]
I fairly rigidly stick to charging my devices from USB batteries, and charging the USB batteries from solar panels. I've read that the draw from phones is more 'controlled', which makes it harder to charge fully - and it certainly seems hard to reach 100% battery on the phone when plugged straight into the solar panels. But sometimes the direct charge is useful.
Anyway, here's my current setup:
- Phone: I'm running a Fairphone 2 at the moment, just because I like what they're doing. So long as you can charge your phone by USB, it shouldn't matter too much. Support for later Android versions is helpful, as they seem to improve the battery life I think?
- Watch: I'm wearing a Pebble Time smartwatch, because the phone is slightly too big to keep in a pocket and I like having (sparse) notifications for messages, etc. The Pebble Time has an OK battery life, and I use GadgetBridge to keep it linked to my phone.
- Solar Panels: I'm currently using a 20W KingSolar array, which has 4 panels, charges 2 devices via USB, and folds up nice. Looks like Amazon don't have the 20W version at the moment, but you can browse for similar things easily. When browsing, it's the Wattage you want to pay attention to - higher Wattage gives you more charging power, i.e. you can charge faster and more when it's sunny, so you can support more and bigger batteries.
I paid £30 for the 20W version, which seems to be a good level for the devices above and batteries below. My previous effort used a 10W Opteka array, which was about £50 at the time - this shows you how much solar panel pricing has dropped in 5 years. I still have the 10W as backup, but rarely use it.
- Batteries: I don't know a huge amount about battery performance, I'm sorry to say. I have 2 USB batteries that I run off, one more portable than the other, but have no idea how to test their efficiency, etc. They seem to do the job though. The portable one is a 10,000mAh EasyAcc power pack, and the heavier one is a 22,,400mAh EC Tech power pack similar to this one.
Choose your battery based on mAh and reviews. For my phone, I get 2-3 charges off the 10,000mAh battery, and 4-5 charges off the 22,400mAh pack, so enough to last me about a week, depending on use.
I've also just added a 20,000mAh Besiter power pack to the collection, because it's sunnier than I can use up batteries at the moment. I'm in the process of giving it a full charge via the mains, then a full discharge on other devices, before solar-charging it. I'd like to add a second portable battery, so that I can charge a portable one up while I'm carrying one around - I tend to use the heavier ones when I'm at home (eg overnight charging), unless it's an emergency.
Whatever you choose, read the reviews a bit. I've found it's useful to have a larger battery for charging up on really sunny days, but I don't want to carry such a heavy thing with me all the time. I don't think it's a good idea to charge one battery from another...
Previously I've also charged up headphones from solar power, which I might start doing again. My Kindle didn't seem to like being charged from a battery, which was annoying, but I don't use it too much.
A future plan is to also revive one of my Pirateboxes, and run this off solar power as a portable wifi hotspot - for p2p networks such as Scuttlebutt?
Oh here's a picture of the two batteries being charged up.
It's helpful to find a standard place to lay the solar cells out, that faces the Sun, and isn't obstructed by shade. I've had spurious results starting out charging in shadier conditions - I'm not sure the charge increases when the Sun comes out more, but need to do better testing here.
2. Battery usage
Once you have the ability to charge batteries from the Sun, and devices from a battery, you're basically good to go. The second useful thing is to then control how your battery is being used - this will sort of come naturally once your phone is being filled with precious, inconvenient energy, but here's what I get up to.
- OS: I'm running Android 6, but will probably switch to 7 when Fairphone release their upgrade. There are apparently improvements to battery life. YMMV with Apple.
- Monitoring: The Battery Usage screen in Android is a good starting point for keeping track of battery train and apps using battery. I also use the BatteryBot app to show me a 1-100% battery indicator on screen, so I can see exactly what's going on.
- Optimisation: There are all sorts of good articles on how to save battery under Android which are worth looking at (I need to revise my own settings all the time too). Currently I'm using Greenify to turn background apps off, but your efficiency may vary.
There are probably similar efforts for Apple, but I'm afraid I have no experience here. Generally, turn off as much auto-sync stuff as you can, including emails, etc.
- For my Pebble watch, I keep all extraneous animations off, and limit vibrations to a minimum. I currently get about 4-5 days of use before having to recharge.
- Software: This is where it starts getting harder, and you have to start considering what you really need to get from your devices. Personally, I have a decent set of apps on my phone, and so long as they're configured right, I can only use them when I need to. There's no straight answer to this except to install stuff, try it, uninstall it, and see if it makes a difference. This is all about battery life vs your own life, so see below for mindsets.
My one guilty pleasure is Pokemon Go, which I play with son 1. This is a right battery hog, especially when there's a lot of screen and network activity (eg during battles). I also find that the live screen when using the phone's camera eats battery up.
Otherwise, battery usage is one of those ongoing battles. After a time though, it can become almost ... fun? A challenge, if you will. Which brings me on to....
This, for me, is the most interesting aspect of the whole exercise. Why do we take electric power so much for granted? How do we know where our power comes from? Why are our devices so geared up for continuous usage, and an addiction to perennial consumption? Why must there be an app for everything, instead of just letting things happen offline?
There are two main aims of running off solar power: first, be resilient by decoupling from megalithic power networks. Dependency on something which you can be cut off from isn't something that the taopunk aims for, so independence is to be valued. Yes, we're still dependent on people making the devices and the solar power and the software, but that's a different conversation :)
The second aim is to rely less on constant power, and to value the potential energy that we do have. It's an interesting exercise to realise that your phone will shut down - and with it, your connection to the whole world - if you fritter away your battery on novelty games. If we want to preserve what we have for later, we need to take our time, relax, find other things to do. Convenience is a luxury, but one we've grown used to. Which isn't great.
So I've found myself much more closely tied to the weather through this. I check the forecast daily, and how I use my phone is dictated by what the weather looks like over the next week. I will hold off heavy usage for a day if it's cloudy and my battery reserves are low. There's a certain hard limit on my tech usage, which I like, and the hard limit comes from nature itself.
That restriction forces some good practices. A focus on Efficiency for one. A push to Do Other Things, to look around and sketch instead of stare at a game, for another. Basic, so simple, yet so forgotten.
Given the current heatwave in the UK, I think I could expand to using all 30W of my solar panels and run off 4 batteries eventually. This, in theory, would keep me going for a couple of weeks. At some point, the weather will switch though, and the solar route will fail me. I'm trying to work out how to get to a point where I can keep going through the winter - should I charge up more batteries? How many would I need to get through, say, October to April? Or should I go full 12V solar panels like a proper nomad?
Anyway, hope that helps. Please do leave feedback here, or via Twitter (@6loss) or via GnuSocial/Mastodon (firstname.lastname@example.org) - I'd love to hear about others' experiences, and any tips for improving what I have. It still feels like there's a lot of potential here...