toroidalcore

Over the years of accumulating renewable energy-related gear, I've evolved several variations of the battery-in-a-box concept. Basically, some sort of portable system with a battery and a charge controller, and other wiring, to be used with solar panels as the primary charging source, for powering whatever. That could include charging electronics, running amateur radio stuff, etc.

In the past I've hard several of these sorts of systems I could grab, usually a smaller one and a larger one. And, enough other crap to throw one or two more together. Right now, I've settled on having a larger more permanent system, which lives in my basement. It's got a 105 Ah AGM battery, charged by 164 watts (nameplate) of solar from three old panels. I might see 10 A into the battery on a sunny day if I've discharged it, but it's a non-useless amount of power – I've run lighting and laptops with it during power outages, for instance, and shift some loads to it on sunny days such as fans.

The recent portable system, however, has a 50 Ah LiFePO4 battery, and a couple of 130 watt semi-flexible photovoltaic panels. (The panels and battery are from Eco-Worthy, and the charge controller is a Morningstar SunSaver MPPT, of which there is another in the previous system I mentioned.) This is technically more powerful, with a little less storage than the permanent system. (Technically you can better utilize the LiFePO4 battery compared to lead acid, but it does work out being a little less capacity.) It's great for ham radio, backup power, etc., and excels of course when the sun is shining – if you have loads you want to run during the day, it's great.

I do have a mishmash of solar panels and batteries, not all of which are used, but I definitely have more smaller batteries sitting around. Sometimes it's nice to be able to grab one for something, and I rotate them for charging. Usually, I do this by putting them in parallel with a battery in one of the other two systems. It's not the most careful way of charging, but if you keep an eye on it, it works. As long as you don't have something set up for an absurdly high charging voltage, like if you wanted to equalize a flooded lead acid battery, you don't really damage anything.

Example: 4 Ah Gel Cell

I have a small gel cell, about 4 Ah, as kind of a lab bench battery. If I parallel it with the big system, with the 105 Ah AGM battery, it might see 14.3 V when that system is in Absorb (meaning, the charge controller is letting the battery sit at constant voltage). That's not too bad, and with wiring drop the smaller battery might pull a quarter of an amp from the bigger system, more if it's more discharged.

Example: Car Charging

I have a cord I made with a power diode in series on the positive side. It has Anderson PowerPoles on both ends, and I also have a cigarette light cord I made with PowerPoles. This actually works out for charging any of these batteries in the car, since the diode introduces a drop of about 0.4 V, and when the car is running the alternator can get up to 14.8 V or so based on my observations. (Actually, this is a guess, I've measured about 14.3 V after the diode while the car is running.) The diode not only keeps the battery from discharging, it also sort of keeps the car from being powered when it's off. This is because I don't really know how it's shutting the cigarette lighter outlet off, I assume it's a relay, but I don't know what else is on that circuit.

This works great for portable radio applications. You just go cigarette lighter –> fuse –> diode –> fuse –> battery –> fuse –> radio. When fusing, keep in mind where energy might come from in the event of a short. For instance, a short in between the diode and battery means current could dump in from both the car and the smaller battery.

Battery To Battery Charger

There are commercial DC-DC chargers out there, and constructing one of my own is on my list. The advantage here is a) having a proper charging algorithm for your battery, and b) being able to charge even if the source battery is at a slightly lower voltage.

That said, this is more complex, and sometimes simplicity is more the way to go. The DC-DC charger is a good idea in something like a camper, however.

Find me at @toroidalcore@masto.hackers.town

So, now for some solid requirements about my solar-powered Raspberry Pi project. To recap, the idea is to have a Pi hosting a small, static website, while powered by just a solar panel with minimal storage. Enough storage to keep it running if a cloud passes over, and to allow the Pi to gracefully boot up and shut down. This Pi would also act as a 'regular' Linux server, that you could SSH into and do stuff on. In other words, not just an appliance with a read-only file system.

Super capacitors make sense here. One of the goals is to avoid using a battery, and a capacitor should have a long lifespan. The current plan is to charge a cap bank with a solar panel, and have that feed the Pi via a linear regulator. Wasteful, but at the same time simple.

I spent some time looking into the Pi's GPIO, in terms of booting up and shutting down. The idea would be something like this:

• Sun comes up, panel begins charging cap bank.
• Cap bank hits Vmin, which turns on enable pin on linear regulator.
• Cap bank hits designated high voltage, Vmax, somewhere between the panel's max power voltage (Vmp) and open circuit voltage (Voc). This boots the Pi via GPIO.
• The panel presumably puts out more current than the Pi consumes, so this stays running for a while.
• The voltage begins to drop due to overcast conditions or, you know, nighttime.
  
• The cap hits the shutdown voltage (Vsht_dn), which signals the Pi to shut down. This also starts a 1 minute timer.
  • The voltage begins to rise again, because the cloud blew over.
    • After the timer expires, the Pi can be booted again via GPIO, if it hits Vmax.
  • The voltage continues to fall, because it's night.
    
    • The cap is sized so that there's a delay of about 1 minute before the Pi drains it to Vmin, at which point the linear regulator is disabled. This keeps low voltage from damaging the Pi.

This is fairly straightforward, just required some thinking on edge cases. And, some logic stuff I'll have to sort out, but that shouldn't be too bad.

Find me at @toroidalcore@masto.hackers.town

So I'm realizing that I kind of like using this as a blogging platform. I want to develop my web site a little, and have a Wordpress blog I use there, but have been thinking about switching to something static-based. And/or using this more. A lot of it is that I need to think about what I really want it to be, and sit down and actually work on it.

I'm kind of thinking that this is a nice place for stream-of-consciousness, generally updates about life. It's a natural extension from posting about stuff on the Fediverse, but still accessible for those not on it. Really, the comments are one of the things that I kind of wonder if I'd miss from giving up Wordpress. It was nice to get one once in a while, but there was also a lot of spam. Plus, email is a thing. In the old days of the web, people set up small personal sites, and maybe publish emails they received there. That could be automated a little, but something like that?

Some sort of scheme to accept comment via email and publish them as updates to static site? Might be interesting.

In the mean time, I just stick a Fedi account as part of the signature here, and get pinged when this actually federates. And I suppose then I could have discussions on Fedi as well, which is kind of slick.

Projects

With US politics being what they are, I find myself a little stressed out. I'm hoping that I can actually devote a little attention to making some progress on things. I do, in tiny, granular amounts now and then. But some of these I've been thinking of for years. Here is a selection:

• Power inverter/battery charger
• Solar MPPT charge controller
• DC-DC converter for microgrid type application, sharing power between DC buses
• Solar Pi, a Raspberry Pi web server powered by a solar panel, such that it's running only when the sun is shining

Really, the inverter is the thing I'd most like to get going. I more or less know how it should work, but as I envision it it will require learning a new microcontroller architecture, and designing a few boards. It will be a bit of an odyssey, but should actually be useful.

The Solar Pi is sort of a concept art project I came up with, and I may put that just beneath the inverter in terms of priority.

Animals

I may be adding a dog to my household. It will certainly be the source of plenty of pictures, as well as of preemption to the above projects, if it works out. Stay tuned.

Distractions

I just try to stay busy. It's easy to get caught in a doom loop. I hope everyone reading this has various ways they can escape the grind now and then. Take care of yourselves.

Find me at @toroidalcore@masto.hackers.town

The 2024 holiday season is about to come to a close, or has already depending on how you look at it. I traveled and stayed with family, and will be returning home soon. It's been a good break from work, a change of scenery, and an opportunity to see new people.

It's also kind of tiring. Yes and no – I get to sleep in, but also have had a few late nights this time around. This is something I'd like to avoid going forward. I also brought projects with me, thinking I'd make progress on them with all that free time I'll have. Well, sort of. I have made progress on some things, but have completely ignored others. That's usually how it goes. I didn't spend enough time before I left on the mental calculation of what I'd actually be likely to look at; had I done so, it may have taken some of the pressure off.

Still, I'm happy I made it out. It's a little adventure. And, we had snow for Christmas! Years ago that wouldn't have been as much of a surprise, but it kind of has been more and more lately.

I have a longish drive to go here/return, but nothing I'm not used to. A few hours. Friends of mine have longer commutes on the order of 1-2 days, and so only make it to our hometown for major holidays.

January is still a little bit of a break. Work shouldn't be too bad, and some other things I'm involve in ramp down a little. It will likely be cold, despite misgivings about climate change and Christmas time, but also cozy in a way. Plus the days get longer.

Projects

Let's see, I'm posting here, which comes with some strife about whether I should make this my primary blog or not. It's a lot simpler than Wordpress, and mentally has a lower barrier, so there's that. A static site generator, however, is somewhere on the list, but we'll see.

The Solar Pi is something I'd like to get running this year. It's just a Raspberry Pi running a simple website, powered (mostly) when the sun is out. There's a good bit to explore there, but it's kind of a concept art project.

Microgrids – specifically DC ones – are something else. Basically, power converters that can share power bidirectionally, between different semi-independent systems. Like, an off-grid PV system that dumps some excess power into running network gear. Yes, grid-tied PV handily solves this, but this should be more fun.

The inverter – something I've had in my head for a decade – is another. That should be fun.

Animals

I thought I might be ending up with a dog, but things didn't work out as I'd imagined. Maybe this year.

In the mean time I enjoy the antics of George, and his feline relatives (through adoption) when he comes with me to visit my parents. The journey is tough for him, but he's happy being with the other cats which is nice.

The nature center I volunteer with is taking a break for the season, but that's always fun.

And That's It

That's all I have right now.

Find me at @toroidalcore@masto.hackers.town

I'd like to attempt writing a Fediverse bot. I have a GoToSocial instance which works fairly well, even if it's still alpha software, and managed to create a bot account and post using a curl command.

I was thinking of using it for posting statuses from my hobbyist off-grid system. Basically, voltage, current, power, and/or energy readings taken off of the charge controller. I already have some scripts in place to do this, so I can read various things over SSH from across my LAN, so it's not that huge of a stretch.

Perhaps it would post once a day, or every hour. I'd probably be the main one to follow it, but it would fun to leave it open for others to as well. One would have to be careful of giving away too much information, but maybe something like daily production would suffice.

I think there's a good bit of potential with bots like this, especially ones you could interact with. That combined with GoToSocial, which has made running a small instance fairly easy (although not entirely trivial) opens a lot of possibilities.

Find me at @toroidalcore@masto.hackers.town

I treat this as sort of like Fediverse microblogging, but slightly bigger. I just wanted to play around with the software, and I like it. But I'm not sure about giving up Wordpress. I mean, I kind of planned on doing that anyways, in favor of a static site of some sort, which I haven't done yet. And yes, I know Wordpress can interact with the Fediverse now.

Every time I think about what I'd like to do with my web presence, I face decision paralysis, enabled by wondering what exactly I would like to write about. So I end up putting it off, but I'm not sure that's a bad thing. I sit on a few domains, and post here and there, and maybe that's enough.

Now I think I'm going to go eat lunch.

Find me at @toroidalcore@masto.hackers.town

New Ubuntu coming out soon. I've more or less settled on it as my daily driver, or variations thereof. For example I have Kubuntu on one machine, and Ubuntu Studio on another. Servers I tend to favor Debian. I've accumulated a few computers, and tend to have them in different areas, depending on what I do. Eg, my main desktop runs Ubuntu, and I have an older laptop I leave in my kitchen, and a more powerful laptop I use wherever.

Ubuntu works for the most part. I'm not the hugest fan of snaps, but it works. I've used Redhat-based distros in the past, but using Debian for servers makes it easier to just use Debian-based distros on the desktop as well, not that it's a huge deal. I've used Mint before, and it's nice. Maybe a little better for someone coming from Windows.

I used to distro-hop, especially back when I was starting with Linux. It was kind of fun, but after a while it became apparent that it's mostly the same group of software. Some things are different, and of course you can go nuts with customizing a slightly off-the-beaten-path window manager. But for the most part, the differences are minimal, and I just kept using Ubuntu.

A pet peeve of mine is responsiveness. Things like applications starting up quick and responding to user actions, not just sheer performance. There are also other little usability things I think common desktop environments could improve on. You can go a long ways without touching the command line on Linux (although it's useful and still IMHO a big part of using a Linux environment), but it would be helpful to have more options enumerated in the GUI. Along with ironing out some inconsistencies in GUIs... Using Digikam on normal Ubuntu (with Gnome) changes the cursor, for instance.

Sometimes you see changes like that in a different distro, other times not. So I don't obsess too much. Now, distros like NixOS are different, and look interesting. Same with something like GoboLinux. But unless I feel like experimenting with one of those, I stick to what seems to work.

Find me at @toroidalcore@masto.hackers.town

My house isn't too dirty, but it's not very tidy right now. I go in cycles of managing to clean it, put things in their place, find a place for things that don't have one, or just throwing them out. That's along with actual cleaning, as the kitchen floor needs right now.

Cat hair builds up of course, as does dust. Then I get water in the basement when it rains, which requires something to the effect of squeegeeing or pumping to manage this. Luckily it's not a lot, maybe a quarter inch of total accumulation down there, but frustratingly it doesn't all flow to the sump pump.

We had a wind storm recently, so I have another round of tree branches down. Good future firewood, yes, but requiring of some work to chop up. And then there are things I'm planning to bring some contractors in for...

Whatever, 'tis all good. My home is comfortable, and looks nice once the cleaning/tidying cycle comes around.

Find me at @toroidalcore@masto.hackers.town

I have multiple computers in my house, a couple desktops and a couple laptops which I use normally. I also have a file server, and a couple other servers for various things. I have a couple IP cameras which are isolated from the rest of the network, but don't really have any “Internet of Things” things. In other words, no network-enabled light bulbs. I do have some things controlled by X10 controllers connected to one computer, but no commercial embedded IoT.

Having a file server, as well as an LDAP directory to sync UIDs and GIDs, I have the makings of an infrastructure you might use in some sort of organization, not for one person. This is convenient when it comes to things like NFS or making backups, but there is a degree of overkill here.

It is kind of a hobby that happens to be useful. Things get frustrating as they often do with computers, but I don't mind being in control. Granted, a big part of maintaining sanity has been getting things to work simply and reliably, so that most of the time I'm not trying to fix things. Sometimes it's inevitable, of course.

Find me at @toroidalcore@masto.hackers.town

Time moves a lot quicker these days, it seems. When I was in high school, a friend (who was about the age I am now) pointed out that when you're younger, a week is much longer in relation to your life than it is when you get older. I can relate to that now, since weeks seem to fly by a lot quicker than they did back then.

On one hand, I still have plenty of ideas and projects I want to attack. Things for the house, life goals, and projects, electrical, musical, etc., that I want to attack. It's actually still quite easy for me to think of things to put on the mental queue. On the other hand, after a long work day, it's nice to just settle down after dinner and watch Star Trek with a cat on one's lap. I fit chores in here and there, and work on little things, but when in that state it's hard to think about the loftier goals.

Finishing something, getting some kind of milestone, keeps me going. Even if it's nothing huge, just getting some kind of finished product is a great motivator. And at least I can say I made it part of the way.

Find me at @toroidalcore@masto.hackers.town