Saturday, April 14, 2018

On the Art of Repair: Re-Capacitoring an Old Mainboard

One of the misconceptions about electronics is that if there are no moving parts, the system should last forever.  This is closer to true than not, but one really common item that does wear out on many systems are capacitors.  Electrolytic capacitors are the usual problem, but, fear not!  You can repair them easily and at home!  Beyond just repairing a mainboard, this week is a bit of a discussion on the art of repair, and why you should get good at it.

Get out your soldering iron and join me!

Saturday, April 7, 2018

Off Grid/RV Lead Acid Maintenance, Charging, and Failure Modes

It's 2018, and if you need power storage, there's a great range of battery options out there.  You've got your bog standard flooded lead acid, AGM lead acid, lithium iron phosphate (LiFePO4), and of course the newer lithium ion chemistries (Tesla's PowerWall being the most well known here).

And, if you're building a system yourself, especially if it's off grid, it's incredibly likely that you're using flooded lead acid, because they're cheap, work well enough, and you can get them in most towns.  They're also quite reliable and can be quite long lived (15+ years) if maintained properly!

But: If you have an off grid lead acid battery system, it only stays cheap if you keep the batteries in good shape and don't kill them in a few years - and a lot of off grid systems end up killing the batteries in a hurry.  This either leads to an early battery pack replacement, or an awful lot of generator use - both of which are expensive, and generally at odds with the ideals of an off grid power system.

I've spent quite a while reading about lead acid from the view of, "How do they fail, and how do I maintain my battery bank to get the longest life out of it?"  I've learned a lot, and also learned that it's really hard to find good information on failure modes!  I've dug through more than one PhD thesis to get information about some particular failure mode.  This is a long post (over 11,000 words), with a lot of information, and I won't apologize for that.  I've tried to explain the concepts as I go into them, with a target audience of people who have large off grid battery banks.  If you want something shorter, maybe check YouTube?

However, if you want to learn how to run a lead acid battery bank for maximum longevity (for your off grid power system or your RV), and to understand what's going on in your battery bank, read on!

Saturday, March 31, 2018

40 Days Without Casual Internet: The Results

A month and change ago, I set out to give up casual internet use for Lent.  I set myself some parameters mostly pulled out of thin air, and tried to follow them.

Did I accomplish it?  Mostly, though not perfectly.  It turns out that purely giving up casual internet use causes a few issues I hadn't foreseen with my whole "blog and batteries" thing, and it's not a good hard line to set.

Also, it was oddly less difference than I expected.  I think this was due to me mostly being sick for a few weeks and traveling more than usual.  Also, I've previously cut internet use down a lot, so there wasn't a huge delta to work with.

Anyway, if you're interested in the results, and how it might apply to you, keep reading!

Saturday, March 24, 2018

Rural Ruin: Old Cabins and Ruins of Civilization

For your viewing enjoyment this week: Ultra-Rural Ruin.  This is an old cabin, easily over 100 years old, that is slowly being reclaimed by nature.  The right side used to be a room as of several years ago, but has collapsed since then.  The rest is very much showing signs of age, the roof is not quite intact anymore, and, well, you can see the rest.

It's not my normal small electronics and battery related posts, but I promise it's interesting!

Saturday, March 17, 2018

Project Pi3Desk: Building an awesome Pi3 desktop with btrfs, USB SSD, zswap, and $30!

Some might wonder why on earth I was doing kernel builds with a Raspberry Pi 3, such that I looked the temperature and throttling behavior.  This week, I explain!  I'm trying to make the Raspberry Pi 3 into the best little desktop I can - without breaking the bank in the process.

I have a few Raspberry Pi 3s in my office, and while they work well for very light utility use (as well as for light data logging and IRC connectivity), they fall down if you ask them to work as a desktop - and they don't really fall down gracefully.  Chrome with a complex tab or two will freeze up a Pi so badly you have to power cycle it, and that's just annoying.  So I've set out to fix it, without spending so much that I'd be better off with a more expensive system to start with.

Interested in how to make a far better desktop out of a Raspberry Pi 3 for an extra $30?  Of course you are!

Saturday, March 10, 2018

Raspberry Pi 3 Thermal Throttling Analysis: The $8 "Moster" Heatsink

This week and next week, I'm talking about the Raspberry Pi 3.  This week, my focus is the thermal throttling behavior - and how different heatsinks impact that.

I'm a big fan of the Raspberry Pi platform - especially the 3rd generation ("Pi3" at many places in this post).  They make great little "light utility" desktops, and great little utility servers.  They're cheap, they're "fast enough," and they're "good enough" to make them fit a whole bunch of roles fairly well.  Plus, they draw basically no power when idle - which matters, a lot, to me, since my office is solar powered and overnight power draw is a thing I'm concerned about - says the guy with the 30W idle draw beast of an inverter...

One downside to the Raspberry Pi 3, at least, is that it runs hot.  It's not a big deal if the system sits mostly idle - the little ARM chip is efficient enough that temperatures aren't an issue.  Load it up, though, and you'll almost certainly see the little thermometer icon on the right side of the screen before long.  On the Raspberry Pi 3, that means it's already thermally throttling back performance - and on stock Pi cooling (none or a dinky little heatsink), it's not at all hard to get that icon to light up.

There are some standard small heatsinks that are sold with a lot of the Raspberry Pi boards - and they're only barely better than nothing in terms of throttling.  But, fear not!  I've found a pretty good solutionA cheap, $8 solution (shipped from eBay).  And it solves another problem in the process - this case and heatsink combo just looks incredibly cool!

Is it any good?  Does the heatsink really work?  How do you detect Raspberry Pi 3 throttling?  Read on!

Saturday, March 3, 2018

Building a Robust Stone Cutting Bench

One particularly warm February morning, I decided that a useful thing for me to have would be a hefty bench I could use for stone cutting.

Why stone cutting?  I have a lot of basalt on my property, and I'd like to learn to do something useful with it - such as turn it into building blocks I can use to make structures.  The raw lumps of basalt aren't terribly useful for that (they have lots of points and are generally oddly shaped), so I'd like to work with them - standing up.  To do this, I built a workbench!  A very, very beefy workbench.

How?  Is it any good?  Should you build one?

Carefully but with plans, yes, it is, and probably not.  Read on!