Saturday, April 28, 2018

PIREPs #1

Or "Pilot Reports."  Number one.  Because this is the first of them on this blog.


Flying.  It's awesome.  I do it.  I'm finally able to do more of it.  Keep reading for more!


Saturday, April 21, 2018

Off Grid System Design Considerations and Battery Types

People are regularly surprised that my solar powered office is driven by a moderately sized bank of lead acid batteries instead of a fancy modern lithium bank.  I mean, I do work on lithium batteries regularly, and I could certainly build myself a large lithium bank at fairly minimal cost (compared to purchasing one, if I were willing to do that much spot welding).  But, in a deck box behind my office, I have a boring set of 8 Trojan T-105RE batteries in a 48V/225Ah (10.8kWh) bank.  Why?


Quite a few reasons - which I'm about to dive into!  Read on!

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!