‘Commonsense’ is what caused much of the world to believe that the Sun revolved around the Earth. For insisting otherwise, Galileo scored house arrest for life. But as physicist/philosopher David Deutsch states, the issue was not so much what revolved around which, but Galileo’s insistence that reason must take precedence over intuition and common sense.

What I’d like to touch on this month is a dissimilar but related topic. It is the difference between understanding as opposed to knowing.  This arises quite often – particularly when attempting to have things fixed that don’t work as they should.

It first came up when an electrician acquaintance (who was about to retire) asked me what size 12/24 volt cables he needed for his coach conversion (an odd question from an electrician). Probing revealed he knew the complex and extensive Wiring Rules, that electricians traditionally followed, inside out. It was his secular memory-enshrined techno-gospel. Via this book, he could wire houses, factories and big office blocks and he did it extremely well.

But whilst his trade knowledge was impeccable he had next to no understanding of its basis. He had come across Ohms Law (the most fundamental of all electrical ‘laws’ that would have solved his motorhome problem) during his apprenticeship, but did not know it now. He seemed unaware of its importance and relevance to his work.

Until the motorhome incident this had apparently never mattered. As he said, “the Wiring Rules tell me what to do”. They cover almost every conceivable electrical issue, but 12/24 volt cabling is not one of them. He said could make a guess but did know not know to work it out.

This is not a condemnation. This man knew how to do his job, but mostly did not understand how what he did actually worked, or why. There are many (mostly older) tradespeople like this who learned their trade hands-on. Many do excellent work: and take pride in doing so. Most times, I’d sooner have a job done this way than by theorists who lack practical experience.

People of The (Rule) Book

But it does not always work!  Problems seriously arise when the ‘People of the Rule Book’ come up against things not explicit in their particular Rules.

Those with a technical background or understanding know how frustrating it is (for example) when attempting to have an RV builder fix a poorly working fridge. And given a tirade about how “we’ve been doing it that way for forty years” etc. . . ..  - and how, “you are using it all wrong”.  Plus a spray for your temerity in complaining.

I talk to RV builders, and sometimes about fridges. So far I’ve met only one who understood that fridges (to quote one of my own books) are “pumps that move hot air from where it’s not wanted to where it does not matter”. Most believe they somehow ‘make cold’ out of gas or electricity. And that exception was previously an ex-policeman turned ex hi-fi speaker maker (a few Members will know who I mean).

If you understand a fridge is simply a heat pump you know instantly that someone who insists that venting does not matter has zero understanding of how fridges work. No matter how professional the gas fitting, or neat the wiring, without ventilation the fridge cannot possibly work as intended (and many don’t).

One vehicle, seen a few years ago had an almost useless fridge. The workmanship was impeccable but the installer demonstrably lacked even elementary understanding. Not only was it totally unventilated it was totally boxed in sides, top and bottom, and located directly over a built-in oven.

Solar Issues

Last month one of my book readers was attempting to fix a solar issue - of batteries running down despite ample power being indicated on the associated metering. This was the tenth such I’ve encountered so I scored (undeserved) brownie points by solving it by email within a few minutes.

In all these cases, inbuilt metering was presenting systems as working correctly in that more energy was coming in than going out. Nevertheless batteries were close to fully discharging overnight.

In each and every case the recommended solution was to replace and/or add more batteries. Despite that making matters worse, none obtained a refund for the 100% wrong ‘solution’.

In essence all were addressing what they conceived to be the problem but in fact wasn’t.
All assumed the batteries were not large enough to store the energy seemingly available. They simply knew that bigger ones were needed (it may even have seemed common sense!). They had in fact advised the right solution. But for the wrong problem.

That problem was: “Why do my batteries go flat overnight when the meter indicates they shouldn’t.” And that problem and its probable cause could have been located within two minutes by:

1. Guesstimating the most electrical energy physically possible from the solar capacity (i.e., go count the modules and check their size).

2. See if (1) is much more than, or much less than you guesstimate is going out.

3. Thinking about what you find.

In every instance, subsequent checking showed the maximum solar output was almost exactly half that shown by the metering. i.e., the meter was showing twice the actual input. In every cases it was twice. That exactness was not by coincidence.

A couple had checked the metering against known loads. That proving correct caused them to assume (for once against common sense!) that the input must be right too. But it wasn’t. All meters were doubling the amount.

The cause (highlighted in my books) is always the same. The solar input is being registered twice. It has been taken to the system side of a current shunt instead of directly to the battery resulting it being registered firstly in the meter and a second time by the shunt.

The actual cause of this is not obvious. But how much understanding does it take to realise that no manufacturer on the face of this planet (especially in the solar industry) is likely to claim just half of what their product can at best do!

No one initially attempting to fix this apparently even questioned that all the solar arrays concerned were seemingly producing close to twice that claimed by their makers. The problems were finally resolved by auto sparkies who’d read my books, or phoned regulator vendors for advice. The above are merely ones I followed up – there must be scores more possibly unfixed.

This one still puzzles me. It should be totally obvious to a professional fixer that the solar capacity in each case had no hope of running the loads concerned. And that adding battery capacity in this situation is like opening a second bank account without depositing more money (i.e., more overhead charge for the self-same deposit). But seemingly not.  

Many readers will have experienced scenarios like this.

To retain even partial sanity, seek someone who has even a tiny knowledge of physics and ask them to assess the problem at its fundamental level, and/or as in the case above, by making a quick reality check.
 
Unless you do this, you are likely to be presented with ‘solutions’ like increasing the size of the gas pipe, or exchanging the fridge for a more costly unit - that is then installed just as before.  Or, in the solar example buying bigger batteries and thus making things worse.

In all cases the Golden Rules are:

1. Define the problem.
2. Check the most obvious thing first.

Collyn says his books “are influenced by the type of thinking outlined here”. (Three of his currently four books are available directly from the CMCA).

The following, from Collyn Rivers, shows how unconsidered things can result in false conclusions.  How many letter ‘F’s are there in the following:

FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS...

Tests worldwide show that only one in five people get this right within a minute or so!  Many never do. There is absolutely no trick.