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.

Saturday, October 15, 2016

Solar Shed: Part 13: Morning Panels

It's the middle of October.  I've been working in my solar powered office full time since July, and so far, all is good out there.  I have plenty of power (so much, in fact, that I'm running Folding@Home and BOINC on sunny days), and even on cloudy days I've been OK so far.  The temperature in the office remains entirely comfortable, and this is, quite literally, the best office environment I've ever had.

But, winter is coming, and power is much like a Spuddie - enough just isn't enough.  I've got 8 panels hung (two strings of 4, as documented here and here), but I ordered 10 panels.  The remaining 2 panels are gathering impressive amounts of dust in my other shed (it lacks a door, and is sitting on some rather uneven ground under where the chains broke through the roof, so it seems to concentrate dust).

Nearly every single morning, as I'm walking out to my office, I see this beautiful east-facing wall, soaking up the sun.  It's full of sun long before my main panels are producing much (while my battery bank is lowest), and it's just a beautiful empty canvas, begging for something useful.

I set out to do something useful with that wall.  Bolting solar panels to the wall made sense to gather that wonderful morning sun - but I figured I could do more.  Winter is what concerns me as far as power goes, and winter sun is low and south.  Being able to swing those panels to face south would be nice.  Southwest would be a nice touch too, should I need it to continue generating power in the winter evenings.

My office being my office and me being me, you can guess that I built such a panel holder!

These panels are normally docked for morning production, but can swing all the way around to face southwest for my "manual tracker" approach to gathering more winter sun.

That's the "What and Why" - for the "How," keep reading!

Saturday, October 8, 2016

Solar Shed: Part 12: Panel Mounts Revision 2

If you were looking forward to this post last week - sorry about that!  I ran across such utter and complete nonsense that I felt the need to offer my opinions on it.  Anyway, back to my solar panels and wooden mounts.

The first generation panel mounts I built for my solar powered office weren't amazing.  They're incredibly stout, and should last through any windstorm we get, but they're simply too heavy.  It's nearly impossible to swing them solo, and they were a nightmare to build and assemble.

Based on what I learned, I drafted a different set of plans for my second generation panel mounts.  Something lower, lighter, and better balanced.  Something that looks an awful lot like this:

Why?  And how?  Read on!

Sunday, October 2, 2016

SolPad: Number Free Nonsense

SolPad.  It's an Energy Experience.  It's a website with zero useful information.  It's a high production quality video.  And what I can find, it's so fact free that it makes makes Jeremy Clarkson look like a fountain of factual information.

And, it's solar.  It's battery.  It's home automation.  It talks to you.  It's a WiFi Hotspot.  It's launching in the "second half of 2017."  And, based on what I can see, it looks suspiciously like a huge load of crap.  So I'm going to offer an overview of it, as well as my thoughts and opinions, based on the available information.

There are two major products covered in the video (and two minor ones).  The first is "SolPad Home" - which seems like a standard rooftop solar panel with integrated microinverter, but also with a battery.

The second is SolPad Mobile.  This is your portable solar energy generator/grid tie energy generator/compass/WiFi hotspot/emergency light/friend.  It comes complete with a "transport mechanism" - that thing, extended out the top.

I'll be going through both, based on the very limited information I can find on their website and in their video.


Keep reading!