Monday, 20 August 2018

New battery for my shed

Well my 3000mAh Li-ION battery arrived today, it has two leads, one for "output" and the other for "charger" ... given that it had to be turned on to charge I was suspicious that it had no electronics and the leads would be the same. As I wasn't sure I opened it up and looked. Below is the only "electronics" that existed in it.

So yep the wires were just in parallel so I could have just plugged it into the charger and left it "un cut" and let the Solar Charge Controller look after the voltages.

You can see that its just three cells in there... something I suspected but wanted to confirm.

So the 12.6V rating is quite optimistic because it will only deliver that for a short time (as maximum safe charge on a Li-ION is normally 4.2V (unless you don't care about their lifespan).

Indeed it says 12.6 - 10.8V ... which is interesting as this means cells are pulled down to 3.6V (you know, 10.8 divided by three) and that's low for a lithium cell as normally you'd want to discharge them to around that at worst case.

None the less in my shed I expect that the lights will be on for no more than half an hour per day ... so all good.

So with the (quite compact) battery now prepped for sticking into my charger....

I did just that:

Of course I'll be measuring actual voltages as we get some time "in service", and not just relying on the controller's set voltages to be accurate (although I've found them pretty close).

But for $15 its pretty decent (well you know).

I'll let you know how it goes.

Saturday, 18 August 2018


I love garlic in my cooking, but I'm not fond of peeling it.

Some years back I found that a couple of Fruit and Veg shops here sell garlic peeled and whole like this:

Its about $3 a punnet like that.

Of course if you're a restaurant this is great, but most of use "home users" without a vampire problem will never use this before it "goes off", however (perhaps because I'm a biochemist at heart) I came up with a solution ...

Olive oil and freezing.

So what I do is tip the cloves into a "zip seal bag" of sufficient size; tip in some olive oil (enough to have all of it covered but not "filling the bag") (important that).

Then pop that somewhere flat in the freezer; making it easy to break off the garlic as needed without thawing it.

The garlic does not "freeze to itself" in a lump because of the olive oil (and what could be more natural than using olive oil in garlic related cooking?).

Win Win

Monday, 13 August 2018

solar shed lights

To me its a no brainer that solar energy just suits small scale projects which don't need to be "on the grid". So with that in mind I thought I'd show you where I'm up to with my small solar shed lighting project.

Some time back I put this small 10W panel on my shed roof, with two things in mind:
First keeping the battery of my pajero topped up and in good order when I went over to Finland for a few months (meaning I wouldn't come home to a dead battery) and
Second being the basis of a lighting power source because running power down to the shed seemed like an enormous pain in the wallet for just a bit of used some times lighting.

So I needed for this project:

  • LED lights (I sort of made them)
  • a battery (scrounged an old flattery from a mate)
  • a IR movement sensor (so as to automatically turn it on)
  • some patience
I made the LED lights by gluing LED strip (bought of eBay for $15 for a 5meter roll) onto some 1 meter lengths of angle aluminium.

This results projecting the light out in a nice diffuse manner basically at the same coverage as the angle, the side reflects quite well and so you get a nice fan. It has the added bonus that acts as a heat sink for shedding the heat from the LED's and helping prevent the glue from separating from the strip.

I then mounted the strips at the tops of the walls, so as to shine light down where I need it (which isn't on the roof of the car all that often).

...and actually when you stand back you can hardly even see they are there.

So that the lights aren't on all the time I've got a small PIR movement sensor after the controller 12V output to turn the lights on when I walk / drive into the shed. As you can see, its just wired roughly at the moment...

The controller is quite interesting, it's very well priced and has some good features. Many online reviews have slammed this little guy because its not MPPT ... well so fucking what? I'm charging a single battery from a 10W panel and MPPT would bring what? 10% more to the table? I could achieve heaps more just stepping up the panel size to 20W...

The pay back is its fucking cheap and has some great features which the online reviews seemed to ignored, perhaps because they don't "get it" in terms of usage (just testing and spec sheet gazing).

What I like about this controller is that you can set a bunch of features:
  • to only engage the load (12V output) after sunset
  • to optionally engage the load after sunrise
  • to individually set how long the load should be available for after those events
  • manually set the battery protection level voltage (the voltage it cuts off the load to protect a battery from over discharge
  • manually set the battery charge shut off level (where it just applies a tiny mA float)
That it will handle a 10A load makes it all pretty good for $30

So, how does it work?

There's still things to do, for example I'm yet to:
  • add a 12V Li-ION battery (which will be much smaller and probably last ages given the loads)
  • mount the controller and PIR onto a board for making it look neater
  • make up an adapter to allow me to charge the battery in the car still, (which would then also run the lights), so that when I am not using the car for a while I can just switch it over to charging my car battery (so its dual purpose)

I'll link to that when I get that bit done.

Friday, 3 August 2018

pumped (by pumps)

Just thought I'd put up an image of the pumps I use in my floor heating system, I guess people imagine all sorts of things, but they're quite compact (and low price).

I buy them on eBay for like $15 each and this allows me to have simplicity on getting consistent predictable flows in my water circuit design.

This batch have been iterative improvement over the previous ones, with the impeller shaft being (what appears to be) Stainless Steel, not a bit of plastic (which broke in a few of my pumps last time).

Given the magnets showed signs of rusting I've used LANOX liberally inside (disassembled the pump which is pretty simple, just 4 screws) to ensure that its well coated with lanoline (which should resist washing off).

I'll add more as I go

Thursday, 2 August 2018

why all phone drop tests aren't worth shit

I've had this phone with Gorilla Glass 4 on it for a little over 2 years now.  I've never had a case on it because I wanted to "see how it went" (having never had a case on any phone I've ever had).

Its been dropped multiple times (like from the first week) as happens despite care, and never had more than a kind of scrape in the glass (you may call it a scratch, but that's a bit finer). These have resulted in something hard (like granite pebbles thrown onto foot paths in Finland for grip) leaving their marks in the glass.

Its fallen onto concrete face first, edge first, corner first and the plastic has done a great job of absorbing the impact without transferring the energy straight to the glass (and it smashing).

Yesterday it tumbled out of my pocket while I was sitting cross legged on the ground and fell like 20cm to the ground. I reached over to pick it up, expecting to just dust it off, and found this fracture:

I was stunned ... totally fucked it in the most insignificant of tumbles.

Looking at that edge (where the shatters radiate out from) one sees this:

The crack radiates out from a point on the edge

so the strike would seem to be right on that rolled edge, so that would seem to be the critical danger point ...  I'm expecting that (as it was dropped onto plain ground) that there was a small stone right there on that roll.

Perfect ...

This would seem to make all the "drop tests" completely pointless because (being brutally honest) it all just depends on how it lands. The luck of the draw so to speak,

This new design is interesting because all the narcissistic personality disorder selfie generation want the new bezel-less phones which pretty much ensure that any drop that hits and edge is going to shatter that screen (and generate new income for the phone maker (or the spare parts maker).


maximizing the exposure to this critical place.

Of course you could always put the phone into a protector case ... which makes it bigger and uglier. But the NPD among us will "imagine" their phone as it was on the corporate advertising, not as it is in their hand.

Corning has progressively enhanced their glass to be stronger and to withstand impacts, but it would seem that the fashion set has fallen for making phones even harder to protect from drops.