Solar car battery charger & WiFi monitoring

The July edition of my favourite nerd magazine, https://www.siliconchip.com.au/ (great magazine, awful website colours/theme) featured an article on Oatley Electronics' 16 Watt solar panel and charge controller combo, for a lean $39 Australian dollary-doos. It even includes 5 meters of cable!

Of course I had to have one, that was a given. Why? Apart from "just because", "solar is cool" etc, the scientific reason is that my less often used old hobby cars really need a battery charger to keep them topped up in-between uses. An Interwebs mail order was completed and praise the universe, it arrived before the weekend. So I climbed on the garage roof, installed the solar panel and wired it up to the included charge controller, and the battery of one of my hobby cars, the 1985 Audi 100 C3. 

But how to quantity my sense of self satisfaction? Easy, ESPHome and Home Assistant of course. I had a few spare power monitors, an INA260 and INA226. These modules are very simple to use, they come with screw terminals and they use the standard I2C comms protocol.

ESPHome has support for these modules: https://esphome.io/components/sensor/ina226.html and https://esphome.io/components/sensor/ina260.html. The INA260 is probably technically superior, because the shunt resistor is internal to the chip rather than relying on an external one mounted on the board. I imagine the tolerances are probably tighter for the internal one. 

(The shunt resistor is a very, very small resistance usually in the order of 0.01 Ohms or less, which the electrical load is passed through in order to measure the current using .. ugh maths ... Fundamentals of Current Measurement: Part 1 – Current Sense Resistors)

Anyway, those two modules and a spare D1-Mini ESP8266 were what I had available in the workshop. A rats nest of wires but it performs the required function, measuring my sense of self satisfaction 😁 The brown figure-8 wire at the top goes to the car battery, the black one at the bottom left is the supplied 5 metres of wire to the solar panel. The charge controller even has USB ports which I've used to power the ESP8266.

One day when I get around to it, I'll share my overall Home Assistant and ESPHome implimentation. At this time I'm up to about 20-ish ESP8266s which do various lighting and sensor duties about the house. This is what the two power monitors look like in Home Assistant:

 

(Yes I know, I wired the battery wire backwards and the current flow is negative. I'm too lazy to either change the wires or chuck a negative "filter" in the ESPHome yaml file. Ironically that would have been quicker than typing this explanation....)

So there it is - in the winter sun at about the middle of the day, almost 11 Watts of energy from the sun. There's a slight loss in the charge module of course, and the ESP8266 itself would be robbing a small amount of power, but a still useful 10 Watts is being fed into the battery of the car. Sense of self satisfaction has been measured and displayed in real time ✔️

Corporate takeovers and formation of planets

The recent buy-out of Red Hat by Big Blue (creating Purple Haze?) reminded me of the Accretion Theory which describes planet formation.

https://en.m.wikipedia.org/wiki/Accretion_(astrophysics)

Essentially, gravitational forces cause particles to be drawn to each other, forming larger clumps of space dust. Eventually, the larger clumps become so large their gravitational pull "sucks in" the smaller clumps that have already formed, leaving just a handful of very large clumps. Or planets in our Solar System.

In this business example, IBM (an already large clump) sucked up Red Hat (a smaller clump) and formed an even bigger clump. Sometimes, a regulator steps in to prevent the clump becoming too big:

https://www.abc.net.au/news/2018-11-09/woolworths-opts-for-plan-b-selling-petrol-buisness-to-ukretailer/10483868

We all shed a tear for poor Woolworths when the ACCC blocked their large-clump-forming plot to offload their fuel stations to BP. Now, thanks to those meanies at the ACCC, Woolworths will only receive $1.7B instead of $1.8B, and the large clump formed by their offloaded fuel stations is just slightly smaller than the Woolworths fat cats dreamed of.

Back to IBM's recent embiggening of their already large clump, does anyone else worry that the world will eventually end up in a similar state to the interesting but frightening future portrayed in The Fifth Element?

http://aliens.wikia.com/wiki/Zorg_Industries

One large organisation, Zorg, seems to operate everything from real estate to taxi companies, food stores to weapons supplies. Of course, we already know Zorg is simply the fictional representation in that movie of the real world organisation, Alphabet (best known as Google).

Way Back Wednesday, Halloween

After my series of mishaps due to not following the simple instructions given in the Audi 100's service manual, I finally got around to correcting my mistakes yesterday evening and the 100 came back to life. Long story short, if it says "you must bleed the clutch if you have also bled the brakes" followed by "you must use a pressure bleeder, don't just pump the clutch pedal", then that's what you should do!

Ebay to the rescue:

I drove the 100 in to work today, completely forgetting it was Halloween because I was so thrilled I could do Way Back Wednesday! Soundtrack included Dire Straits, Fleetwood Mac, The Beach Boys, INXS and those two annoying British dudes, Black Lace.

On the way home, I noticed the gear change felt consistent during the whole trip. I have a theory that because the clutch hydraulic system had air in it (plenty came out during the pressure bleeding exercise!) the pedal wasn't always fully depressing the clutch inside the gearbox, causing the gear shift to sometimes be difficult. Anyways, it was a delight to drive and I can't believe I didn't do that brake/clutch bleed thing correctly in the first place, 6 months ago!