An Eccentric Anomaly: Page 3: Houses

Ed Davies's Blog

Pages tagged: Houses

House construction, energy efficiency, etc

Site Piccies

As noted previously I've bought some Scotland. It's about time I showed it off a bit.


Bought Some Scotland

The last full week in September was quite a good one from the point of view of my house build project.


Roof Rethink

Over the last few months I've been having a little re-think on the structure of the roof - not a trivial aspect of an A-frame house.


Five Months!

Bleedin' 'el - it's been five months since I last posted about this here plot purchase.


LiFePO₄ Efficiency

Having just carefully charged some LiFePO₄ cells and also just read a thread on the Green Building Forum about battery efficiency I decided to do a little science and measure the efficiency of these cells.


Charging LiFePO₄ Cells with a Maplin N27GG Bench Powersupply


As previously mentioned, I have 10 of these 20 Ah LiFePO₄ cells. They've been in storage for a year and I was getting a bit concerned that their self-discharge might be reaching the point where they'd damage themselves by going under their minimum voltage so I fetched them and gave some thought as to how to charge them.

When I was playing with them before I used the 12 volt gel cell charger which I previously used for glider batteries, basically as a constant current source. This is not very satisfactory as the charger gets quite hot in the near-shorted state charging a single 3.3 volt cell and you have to watch things very carefully to make sure you don't overcharge the cell.

That was for the initial conditioning charge (when you first get these cells you need to charge them to 4 volts first time, then charge to some value a bit less than this subsequently) and for additional playing. Most of the time I was using them on my little solar panels with a Morningstar TriStar MPPT controller.

Inspired by Outtasight I got a Maplin N27GG bench power supply from Maplin in Blackpool while down that way on a family visit. It's in some ways quite cute but in others quite horrible. The first one I had blew up, moderately spectacularly.


Limbo Dance

I continue to exist while waiting for the crofting situation with the plot to be sorted out.



My previous Decrofting post summarises the situation with the purchase of the plot as it was at the beginning of November. Since then not a lot has happened but just about enough to be worth reporting.


Which is more scary: volts or amps?

It both amuses and scares me how people are frightened of high voltages but often seem amazingly relaxed about low-voltage high-current situations.

High voltages are relatively easy to deal with. Wrap them up so people can't contact them with bodily parts and put an over-current protection device (fuse or circuit breaker) in the way so they're not likely to start a fire. For extra points, put an RCD in the circuit to defeat those more intent than normal on a Darwin award and even an AFCI to stop relatively small sparks causing fires.

High current circuits, particularly DC ones, are intrinsically harder to make safe even at low voltages as any poor connection, with higher than nominal resistance, can dissipate significant amounts of power as heat and so, maybe, cause a fire. Over-current protection doesn't help as normal operating currents can cause such problems.


Components and Layers in Google SketchUp

I've been doing some redrawing of my house designs in Google SketchUp. SketchUp is generally pretty well thought out and impressively clever at working out what you want it to do except the odd occasions it isn't at which point it can become seriously frustrating. Here's something which has a simple explanation which took me a while to figure out.