Saturday, December 3, 2016

A Tale of 3 BionX Packs: Self Balancing LiMn

I've worked with a lot of BionX battery packs over the past two years - stuff I've torn apart, stuff I've rebuilt.  The older packs are an interesting series of packs all built around the Sony US18650V 1600mAh LiMn cells, and these older packs stand out, in a way, by what they don't have.

They don't have a balancing BMS or any balance leads!  Instead, they have cells that, at least on paper, claim to be self balancing.

How well does it work in practice?  Perhaps surprisingly, very well!

I have a selection of live packs to play with (old and worn out but still holding a charge) - read on and let's find out how well some old BionX packs are balanced!

Saturday, November 26, 2016

DSO138 Scope, Acrylic Housing Assembly, and USB Power

Every now and then, I find out about something that is simply absurdly cool and useful for the price.

The DSO138 oscilloscope is such a device - you can get one for $25 on eBay!

This is a 200kHz-sample-rate oscilloscope that is normally sold as a solder-it-yourself kit for students and hobbyists to assemble.  However, if you don't feel like soldering such a thing together, you can just buy a pre-assembled unit.  This is what I did, as I'm way more interested in a working scope than yet another soldering project.

Output is on a built in 320x200 LCD, and the system supports from 10mV to 5V per division, and a timescale from 10us to 500s per division.  It also has some built in analysis and a signal buffer that one can use to freeze a waveform and look around.

Is it fancy?  Certainly not.  Is it $25 shipped?  Yup!  I'm willing to forgive a good bit for that price.

I've spent a bit of time with mine.  There are plenty of reviews and thoughts in video form, but my review is in text form, because I don't like using video for things like this - sorry, everyone who wants me to do video.  I've also assembled the standard laser-cut acrylic case, and I made my unit USB powered instead of 9V powered, because I like things that run on USB battery packs.  I have enough USB battery packs laying around (Ingress player and all) that I can run USB devices anywhere, for absurdly long periods of time.

Interested?  Keep reading!

Saturday, November 19, 2016

Installing the latest AT firmware on a 4Mbit flash ESP8266 (and others, too!)

One interesting experience with the ESP8266 modules, as received from Amazon or eBay, is that they come with a huge range of firmware versions, and a huge range of flash chip sizes.

Some of them can self-update to some version or other, but I've found that this isn't particularly reliable - and doesn't work at all on the cheapo versions that ship with a 4Mbit (512kb) flash chip.

In this post, I'm going to show you how to easily update an ESP8266 module (I use the ESP01 and ESP02 because that's what I keep around) to the latest firmware - currently AT version, SDK version  These instructions should remain reasonably current, though if the instructions stop working, please let me know in the comments so I can update this post!

I explain how to build some ESP8266 test/configuration/updater boards, so you can have one handy for all your projects.  And then, I provide some documentation on how to actually update the firmware - even on the 4Mbit flash chips.

Here's the result: The latest firmware.  On everything.

If you're at all interested, read on!

Saturday, November 12, 2016

Replacing the Fuel Pump in a Kipor IG2000 or McCulloch FG2000 Generator

A rebrand of a knockoff Honda generator, obtained used, for cheap, has problems!  I'm entirely unsurprised (unlike most of the rest of the country, right now).  My fuel pump has started leaking, and my oil level switch sticks when cold.  I've solved both issues, in two very different ways.

I have some thoughts on Trump winning that I'll share at some point in the future once things have cooled down, but this week is something non-political, mechanical, and only slightly messy.

What exactly is my generator, why do I have it, and why did I go with this one?

I've covered this in some detail in a post on backup power for my solar powered office, but in short: This is backup power for my solar office - given sufficient clouds, my panels aren't enough, and I do earn a living out there, so need reliable power.

Of course, I don't plan to use this much, so I got a cheap generator.  This is a rebadged Kipor IG2000.  A Kipor is a licensed clone of the Honda inverter generator (or a reverse engineered knock off, depending on who you listen to), sold for much less money, and generally regarded as somewhat crappier and less reliable.  Given that I just bought a Ural, you can conclude that I'm probably OK with less reliable devices.

If you're interested in pulling one of these apart to replace a leaking fuel filter, or you've got a problem with your oil level sensor, read on!

Saturday, November 5, 2016

Trek Transport+ Battery Teardown (with a new record negative voltage)

It's another week with a battery teardown!  What do I have on my bench this week?

This is a Trek Transport+ battery (BionX powered).  It's reasonably similar to the Valencia Ride+ battery (torn down in two parts), but there's no hump for the battery management board.

So what's inside?

Well, in this one?  A little house of horrors.

But you'll want to read on, won't you?

Saturday, October 29, 2016

Tesla Model S 12V Battery Analysis

It would be great to be able to start this post talking about how the Model S, much to the amazement of many owners, has a 12V lead acid battery.  Sadly, I can't do that - because this battery is a failure-prone sore point among many owners, and far too many owners with a >2 year old car are entirely aware of it, as the battery has already failed and been replaced at least once.

This little gizmo is the cause of an awful lot of unhappiness with the Model S.

I don't own a Model S, but I do know a little bit about batteries - and while most of my work is with lithium battery packs, I also know a bit about lead acid batteries, as my office uses a good sized bank of them (about 225Ah at 48V, depending on rate) for solar energy storage.  No, I couldn't get my hands on a PowerWall, and no, one wouldn't even be useful to me voltage-wise.  Though if you have one laying around you'd be willing to part with, let me know...

Anyway.  I was wandering around the internet and came across something interesting.

I've got, on my flash chips, this tiny little file that, on analysis, turns out to be a few days worth of data log from a Model S 12V battery system in late 2016.  Voltage, amperage into or out of the battery, and some surrounding data about charge state and the like.  Rumor has it that the power settings are "Energy Saving : Off" & "Always Connected : On."

So, in I dive!  Chart a course to graphs!

Saturday, October 22, 2016

Solar Shed: Part 14: Backup Power

I've just finished three posts about how I mounted my solar panels for my solar powered office (panel mounts revision 1, panel mounts revision 2, east facing morning panels).  I've got 2850W of solar panels hung for an office that can run, in a pinch, on just over 200W.  But winter days are short, winter days can be dark, and winter can have inversion layers out here that lead to a month of clouds in a bad year.

So now, after all the solar panel discussion, it's time to talk about my backup generator - a key part of a balanced breakfast solar powered office.  Really, they're needed for any off grid system.

My generator is a rebrand of a knockoff of a Honda inverter generator - and it works great!  Read on to see how this hooks into the rest of my system.