Tuesday, 12 November 2019

Experiments in USB batteries + solar controllers

Current status: Can you hook a USB battery up to a cheap solar controller using a 12V-to-5V converter? I looked in online forums a lot and couldn't see anyone saying you couldn't - to be honest, I couldn't see anyone asking either. So. Punk it - 20 quid and some sunshine and let's find out:

60W panel top right, going to solar controller in blue on the right via a DC cable. Then through the converter mid-bottom-left, out through the USB voltage metre in the middle, to the battery bottom-right. 

And technically, yeah, the battery still charges. Initial tests show the output from the controller swings around a lot more wildly than plugging the battery straight into the panel, which probably makes sense as we're in unchartered territory? And the panel makes a high pitched noise but I read that that's a common thing cos frequencies.

I feel like it sort of works, but (instinctively?) maybe I'm more likely to kill the battery faster cos of the power fluctuation. And I haven't seen what happens when the battery is full - it should probably shut itself off, unlike a lead battery. The use case is really when the sunshine is patchy, or I want to put the panels out but the sun isn't up yet. Need to run some tests when I'm at home on a partially-cloudy day. Maybe that'll happen now the weather is getting cold and crisper.

On the plus side, still going strong despite a long run of wet weather recently... 

Friday, 18 October 2019

Current kit photos

As sun is a rarity this month, I'm getting a little tetchy about battery usage now. The weekend should bring something though, so I'm hoping I'm in the right place at the right time. Sometimes I think my solar harvesting is more like trawler fishing than crop harvesting.

In the meantime, I thought I'd gather together all the kit I'm running for a few "family" photos. I missed out a few things, but I think it's nice to see what it largely looks like for real. Maybe I should even start videoing this stuff? 😐

So here are some pics - I've also added them, with more detailed info about what's in them, to the new Kit page on the blog. I'm hoping to start building up a bit more of a reference guide here, now that I have some bigger pockets of time around.

The panels:

The batteries and cables:

The devices:

Thursday, 10 October 2019

The Challenges of the Joy of Autumn

Autumn has traditionally been my favourite season, the recuperation from the haze of summer, heralded by muted rainbows emerging from trees. The promise of cozy evenings ahead, yet still the warmth to enjoy the air, a sense of work done, crisp and fresh smoke-tinted breezes.

Past the autumnal equinox, solar power becomes much more of an active challenge. Gone are the lazy days of sunshine embracing waking hours from beginning to end. Long shadows and longer nights cut in round buildings and jagged trees, slicing up beams into bursting energy sources. The sun moves fast across the sky and all the cherished angles have shifted, threatening precious efficiency powering your settled routines.

But this challenge is part of the seasonal cycle, and what makes solarpunk gorgeous. Nicholas Haney asked whether Solarpunk is a Pagan thing, and noted that "we face a lot of challenges in the days ahead ... I think we can build a renewable civilization and weave nature and culture back together." And weaving technology into the strips of sunlight, every day the sun gets lower is another day I'm thinking about the fragility of energy, the dependencies of this net that surrounds me, and the assumptions of my every action.


I have retreated my panels to the top of the garden, and am noticing how the extra battery and larger panel make such a difference this year. A tropical season has settled, with most days being fairly grey or wet. Heavy showers with fat droplets have swept through overnight this week, accompanied by large marshmallow cumulonimbi clouds worrying the charge controllers buried in my batteries like sleeping worms. A few minutes of heavy cloud has the potential to switch off the charging circuits.

Fortunately, there have been enough cloudless days - or, rather, days which are bright enough, when the cumulus shapes have given way to more strata-like formations, acting more like a lightbox than a puppet show. My 60W panels have given me a real boost - overcast days still often have enough voltage in them, and even though the days are shorter, a sunny day or two means I can mostly max out one of my larger (20,000+ mAh) batteries. 60,000 mAh of storage is enough to last at least a week if I really want, so when I've not been able to charge up, I've still had one whole battery on standby.

This contrast shows how one can run a 'second level' of USB-based solar power these days. Where 'level one' is probably under 50W, 30,000 mAh, and costs under a hundred pounds, its usage is limited to optimal conditions. I feel like I'm a stage up from that, and a step down from doubling the cost, and being able to bring in a solar controller for more automated sufficiency.

But currently I still enjoy putting the panels out in the morning, taking them down like washing in the evening. My main enemy is the wind, in the these parts - the few times I've put my panels on top of an aging shed, I've come home to find the panels down in the garden waste, blown off by the strong south-westerly whirling around. My new battery has luckily had its fall cushioned by decaying iris branches, but I don't want to continue the risk.


Still, I don't think this will work well for the winter months. Yet it seems a shame to waste the sunshine based on my routine, rather than my technology. I'm around the house a little more these days, which means I'm able to grab a sunny patch when it coincides, but that leaves a fair few days where the shadows and schedules still conflict. I'm over 6 months in, and don't feel threatened by shade like last year. Let's see what happens.

Thursday, 22 August 2019

Autumn creaks and preparations

August 22nd, and I'm getting some creaks. Mentally, I still think it's mid-summer which might be true-ish for temperature, but not for light. We're now 2 months after the solstice (1 month until equinox!) and the shadows are shifting rapidly.

The daily pattern of shadows affects me depending on my daily pattern of life. It's easier to work around the shadows if I'm around the house during the day - but if I'm out, like at work, then it's trickier. I still suspect that the electronics inside some of my batteries throttle the charge if it's too low, and don't unthrottle it when it picks back up again. If I start my panels out in shade, then I don't seem to get much charge even if the sun hits them for a full day starting half an hour later.

I think I'm going to need to look into solar controllers more... (Or work from home 😏)

I'm also being confused by my batteries not charging properly with certain combinations of panels. Having run some tests yesterday using my USB power measurers, I'm now fairly sure my big old red battery is playing up, so maybe it's time to replace it. But it seems to have a knock-on effect when I plug in a different battery to the same panel, and I get the same charging problem - but then a while later it seems to work. Hmm.

I was out collecting the first crop of early blackberries yesterday, and the strawberries in the garden are dying away and rotting now. Autumn is on its way, and it feels like time to start preparing.

Wednesday, 7 August 2019

Recharging the batteries - a holiday roundup

Status: 4 months complete.

This year's family holiday was to the same French campsite we went to last year. This made it a little easier to plan - see last year's notes for what happened - but the biggest differences this year have been a couple of changes:

1. I am so full of batteries now. The sun has been good in the run up to holiday, so I was pretty much full up to go away - the usual ~79KwH worth of batteries I have now is way enough to keep my phone and watch going for 10 days, whatever happens.

2. Learning from last time, I knew that the biggest battery sink for my phone is taking pictures and videos. This year I decided to keep my photography simple - I didn't even take a film camera! 😁 Instead, I picked up a little Apeman 4K device which I can charge up via USB - the efficiency of a separate device, rather than piggybacking photography on top of a whole phone OS, is huge. I've been taking a bunch of footage, and needed to charge up the camera battery once every few days.

3. Relaxing on holiday is great - I've got free data roaming (thanks Europe!) so it's not been expensive at all to use Internet on my phone. But I've been reading books and magazines and drinking wine, mostly. The phone has either been idle or off, apart from the odd bit of GPS when visiting strange new towns. I've also been posting a few postcards via email and am really loving email for status updates, without all the overhead of a web browser.

4. I've had so much battery, and used my phone and watch so little, that I've been able to charge up the camera, plus my wife's iPhone, from my batteries without too much worry as well. I've brought my 20W solar panels with me as a bit of a top up, but either the clouds have been too cloudy, the panels are struggling, or I'm spoilt by my new 60W set - I haven't had much luck charging up my battery anyway. I've had something, so I think it's just not being able to get a full whack of sunlight.

I'm starting to get a bit low on battery now - here's hoping the sun comes out for a few days when I'm back home...