George Behind the Workshop

It is with great sadness that I let George's followers know that he suddenly, unexpectedly, and peacefully passed away at his home in September. 

George was my father. He was a brilliant problem solver and was passionate about conservation and the outdoors. He was the type of person that could fix almost anything and saw the value in reusing, re-purposing, and re-engineering. He enjoyed cooking and had a gift for breads and an endless enthusiasm for learning, on an eclectic range topics. The last books on his kitchen table were "Engineering in Plain Sight" and "Open Circuits: the Inner Beauty of Electronic Components".

I'll miss a lot of things about him, right down to the incredibly packaged parcels he would send a few times a year for special occasions. If any of you have ever received a physical package from George, you'd know that the packaging itself was almost always as impressive as whatever was contained within.

I'm sorry George didn't have more time. I'm sure there were more interesting projects in the works and a lot of events that his family would have liked to share with him.

It was his wish that his websites remained open. So please, continue to read, share, and enjoy the interesting and handy guy dad was. 

Best, Jessica

reader project 7

 

 

 

 

 

 

 

 
 

 

 

 

Nicolas Cretton is a teacher in Lugano Switzerland, near Milan.

He sent the following links to work done by his students. (Italian Swiss):

http://www.nicolascretton.ch/LM/LAM_Grueninger_Kunnakatt_Marcotullio.pdf

http://www.nicolascretton.ch/LM/LAM_FINALE_12_2_2014_finale.pdf

http://www.nicolascretton.ch/LM/LAM_Bizzozero_Casiraghi_Keller_2015.pdf
 

June 3 2024 Hello George,
yes, I did send this at the time. You are welcome to use these links, they are publicly available on my website.

You are absolutely right about the challenges outdoors: indeed I had to replace the mylar already once, because after a few years, it oxidized and became white, not reflecting the light as before.... I'll have to do it again after only 2 years after the last change... 

A few months ago the motor I have been using died and I have to replace it.

Although I painted the wood structure with a water resistant paint + a coat of waterproof vernice [varnish?], it is now full of little black dots (mould I guess)

So all in all, if I think of all the work, it would have been much easier to install photovoltaic panels, which require zero maintenance and we could have used them also for heating the house, since we have an electric heat pump and we could have sold the excess electricity in the summer. I already have 15m2 of vacuum tubes for hot water (shower) and a bit of heating. I could send you pictures of the installation, after 10 years, to see how the degradation took its toll... thanks Nicolas 

 
I remember that when I started this work, solar PV cost $8-10 per watt.
What a different situation now!

Thank you for your interest

George Plhak
Lions Head, Ontario, Canada 

 

reader projects
reader project 0
reader project 1
reader project 2
reader project 3
reader project 4
reader project 5
reader project 6
reader project 7 - This article

 

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Thanks for your interest!
George Plhak
Lions Head, Ontario, Canada

 

 

CO2 meters

Remarks on some of the inexpensive CO2 meters I am testing.

Showing CO2 readings from 5 meters in my office. My own breath over a few hours while in a smallish 10x10ft office room with one door open to the rest of the house. Only me in the house (plus a cat).

I had hoped the initial results would be more similar but I do see them converging with time.

[click the picture to enlarge]

The cat and I emit CO2 constantly and we move around the house so the meters fluctuate. There are some tiny seedling plants in the house but probably insignificant CO2 sinks so far so our household CO2 should be reasonably steady. Other gases should not cause deviations. The meters should be specific to CO2 but I've found that the cheaper meters react to other gases.

Please note the range from 623 to 795 (CO2 parts per million), even among these "better" units.

One hour later the average rose to "around 800ppm" where it remained more or less for the day.

800ppm is a NOT a serious level of CO2 in my home but it is worth it to know the relative level.

The meter readings track together but there is a lot of variation. The meters update at different intervals. If I took the same picture 10 times, all would be slightly different. Digital makes one crazy with apparent precision.

I did learn that the CO2 detector inside the meter should be a NDIR (Non Dispersive Infrared) type sensor specifically to be at all useful. The price of NDIR units is typically $50+ (and up to $800 or more).

These are all NDIR meters. The most expensive of mine so far cost about C$200.

In the morning when I first enter the office, the meters will typically show "around 400ppm".  Home heating is on and windows are closed (Canada winter household conditions).

These meters are Li-Ion battery powered and will run for about 6-8 hours or continuously if plugged in via USB. They work great in the car or in your pocket or on the meeting room table.

If I leave a CO2 meter outside (or in my garage) some will read down to 350ppm at times. That is the background CO2 level here which is going up with time but is difficult to measure. Interestingly some of these meters will not read or display below 400ppm at all.

Some NDIR meters will do an automatic baseline (ABC) calibrate function to eliminate the effect of drift. You need to leave them in place for while (days or weeks to stabilize then move them outside for a time occasionally) or follow the hopefully provided calibrate instructions.

Cheaper meters do not use NDIR sensors and are only so-so with CO2. They do not discriminate well other volatile organic compounds (VOC's) like cooking vapours, alcohol or cleaning agents so will show high values sporadically. The cheap meters will drive you crazy with false results. I have about 20 of them.

CO2 meters will also typically show temperature and humidity which are not necessary, related or required for a CO2 measurement. The temperature/humidity are separate inexpensive sensors inside the unit, separate from the CO2 sensor..

More measurement types (3in 1, 5in1 or even 6in1) are not necessarily better than one good CO2 measurement.

Please see my earlier article about the meter at lower right (HT2000).

More soon.

Postscipt Apr 4 2022

Same setup a couple of days later.

I notice that the meters now typically cluster within 75-100 ppm of one another.

It seems that they have become accustomed to the room or each other or perhaps the autocalibrate is having an effect over time.

Thank you for your interest.

George Plhak
Lions Head, Ontario, Canada 

home electric blog index (new)

Ongoing series since 2014 about managing my home energy.
Click any picture to enlarge. Use BACK to get to this new index.
A work in progress. Comments welcome.

intro
home electric progress
home electric progress 2
home electric progress 3
home electric progress 4
mcmaster study
flexplan/blueline/energycloud/plotwatt update
measurement
the base load
my typical electrical day summer
my typical electrical day winter
my typical electrical day winter 2
measurement and control
measurement 2
major appliances
infrared camera
dishwasher
exposing my dishwasher energy hog
more on time of use electricity
more TOU and dishwasher continued
water heater
water heater inhibit to save peak time of use cost
the old water heater
the new water heater
water heater update
heat
heating degree days
heating degree days 2
heat
heat 2
heat 3
heat 4 - the new furnace
chimney cap
refrigerator
refrigerator
superinsulating my refrigerator
insulated refrigerator freezer result negative?
insulated refrigerator freezer 2
EnerGuide refrigerator test specifications
refrigerator 4
refrigerator 5
refrigerator 6
freezer
freezer
freezer 2
freezer 3
dehumidifier
dehumidifier
dehumidifier 2
other
the ontario grid - ieso and sme
conservation
efficient workshop lighting 2
clothes dryer heat recovery

Thank you for your interest.
George Plhak
Lions Head, Ontario, Canada

chimney cap

INDEX to the series

Before

Capping my old chimney will hopefully reduce my home energy use.

This chimney has not been required since the old oil burning furnace was removed.

Covered with a tin roof and screen, the old chimney was essentially an open tube from the roof down into my basement.

Although closed off at the bottom, this steel lined pipe was open at the top allowing convective flow from the top of the tube all the way down through the brick chimney core. In other words, some of my expensive heated air was rising out the chimney. Cold air was replacing it by sinking down to the lowest level of the house, right through the center of the house, without much insulation around it.

About stack effect.

The new propane furnace installed three years ago vents through the wall of the basement so this chimney is no longer required. In a major renovation, a chimney like this might be removed entirely from the building and covered over at the roof line but that is not in the plan.

So the next best thing seemed to be cutting the airflow at the top in a permanent waterproof manner. I finally got around to this job three years late. I hate working on my roof.

Above was the top of the chimney showing the 7 inch diameter stainless steel liner and the old chimney cap. That was a pretty large opening into my house!

I used a cutting disk in a grinder to cut through the steel level with the stone and discarded the cap.

On the level surface I laid a bead of mortar then set the patio stone onto the chimney.

Once the mortar had cured, I added a layer of fibre glass tape and roof sealer to the joint.

After

Thank you for your interest.

George Plhak
Lions Head, Ontario, Canada

INDEX to the series

polishing headlights

Improving 14 year old headlights for about $25 and a few hours easy work. 

Most of the time is to allow drying after each step.

I used 1000, 2000 then 3000 grit 2 inch sanding disks in a drill to wet sand, followed by hand sanding then washing and drying at each step. Then I put on gloves and applied Wipe-New.

I had not used Wipe-New" before. The result is impressive.

The "AFTER" picture
<click to enlarge>

 

 

 

 

 

 

 

 

The "BEFORE" picture

The headlight as it was with masking tape applied to the surrounding paint.

Hard to believe it was this bad.

Three steps of progressively finer sanding disks were used wet followed by cleaning and drying after each.

Machine sanding with the drill was followed with hand sanding with the same grade pad at each step.

New sanding disks were used for each headlamp at each step.

Wipe-New back of package

Contains:
tert-butyl acetate,
1-choro-4-(trifloromethyl)
benzene and benzaldehyde.
Wear gloves.
Use outside.

Have both headlights prepared before you open this package. It evaporates very quickly.
Wipe each headlight only once to coat the surface.
I went in horizontal strips.
The applicator works well.
Do not try to touch up.
Wait for an hour.

Wipe-New package

Wipe-New product link

I bought at Canadian Tire for about C$20 +tax

    The live action "TECHNIQUE" video

 

The final result.

I am very pleased!

I will see better in the dark and will not confuse on-coming drivers.

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

fixing old stuff

Troubleshooting two big old Tektronix 7854 in my garage. The first analog oscilloscope with a computer. An oscilloscope lets you "see" electricity.

 

Currently I am checking the LV power supplies. I think I can operate them completely out of the scope.

 

I hope it will be an advantage to be able to compare one scope to the other. I have already found a few things

 

I have the 3" thick paper Tek manual with beautiful foldout diagrams and all the update pages (late issue).

 

And I have a third working 7854 on a cart in the house. I can always open that one up too :)

 

Why do this?

 

These scopes might be forty years old. A modern $400 oscilloscope from China does more, better, smaller, lighter, and is way cheaper (but probably not with 400MHz bandwidth).

 

The 7854 was introduced in 1981 at a base cost of US$10,500. In my 1987 Tek catalog it lists for $16,220 but by then included the waveform calculator and the extra memory option. Project Leader on this scope was Tom Rousseau. More about Tom and the 7A26 amplifier.

 

Some people collect old cars.

 

Thanks for your interest.

 

George Plhak
Lions Head, Ontario, Canada

 

easy change

John Deere Easy Change oil system

Today I tried to change the "Easy Change" oil filter on my cute little John Deere E120 lawn tractor. I am supposed to easily remove a canister that contains the filter and about a third of the engine oil and replace with a fresh unit. No need to drain the oil, they say. Cost locally at Home Despot is C$70. They call it Easy Change. First time I have tried it. It was anything but easy.

 

Normally, an oil and filter change takes about a hour if done carefully and costs about $20 with good quality oil and filter. Virtually all of the engine oil gets replaced with new, not just a portion.

 

But I am stuck. The old canister came off with some effort. Push and turn counterclockwise they say. Difficult to remove but it seemed to come off OK.

 

The new filter did not lock into position as it should. It is in the middle and it is really stuck. There was a click but I cannot remove it or force it to the fully locked position

 

In a conversation this morning with my local JD dealer 1 hour away they say "put the tractor on your trailer and bring it in. We will get it off for you while you wait". Thanks. I don't have a trailer.

 

<more conversation with the dealer>

 

I am going there tomorrow to get the parts to remove the "Easy Change" oil filter system and replace with a conventional filter and drain port.

 

JD equipment with an Easy Change oil system can be fixed. 

 

It is a bad idea that can be retrofitted for less than the cost of one canister.

 

Big Thanks to <my local JD dealer> for help.

 

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

 

 

infrared camera

INDEX to the series

In my never ending quest to reduce household energy use, I have added a Hti-Xintai HT-18 Thermal Imaging Camera to let me see HEAT.

First day reaction: this is VERY COOL.

I can now see an accurate temperature image from a distance on a small handheld display. But not thru glass.

In this picture, I am looking at an inside wall and noticing gaps in the insulation.

A whole new infrared world has opened for me.

This is my wood stove at moderate heat in the infrared (IR, below visible light).

The WHITE marker at the image center (126.2C) shows the temperature at that point. The value is also shown in the upper left. The measurement point is on the door, just off the window, where I happen to have pointed the HT-18 when I pulled the trigger to take the picture. This is the center of the instrument.

The RED marker above and to the left of center (145.7C) is the warmest point on the image. That value is also shown on the bottom line as MAX.

The GREEN marker at the top left is the COOLEST point on the image (14.2C). Also shown on the bottom line as MIN. The MIN is near the bottom edge of a window so it would be cooler.

When watching the HT-18 live, the red and the green markers move around on the screen as conditions change. They can be turned off since they can be distracting.

The bottom line can also be turned off.

Bottom right is the time of day.

At top center right is the emissivity setting. The default is 0.95.

Top right is the battery condition. I have been getting several hours at least on a battery charge.

Interesting about the wood stove is the camera's inability to see through the glass in the stove door to the very much hotter embers of the fire inside the stove. This is related to the emissivity of the glass. Smooth shiny surfaces do not emit well. 

It is fun wandering around the house with this.

HT-18 has two cameras, one "sees" normal light, the other infrared (IR).

It is possible to see (and take pictures of) visible, IR or varying overlaps of the two on the built in display.

In this pic, I have shown the visible image of my gas furnace on the left and the IR image on the right as two separate pictures taken one after the other. The furnace has just finished operating.

The scale at the right shows the colour code from white (HOTTEST) to black (COOLEST).

HT-18 has 5 different color code scales, selected in the menu, two are B&W (no colour).

This GFI outlet upstairs has nothing plugged into it. It has no load yet it is slightly warm!

This is normal.

The tiny circuit which operates the GFI sensing consumes electricity and warms up.

When I put my hand on the outlet, it was barely warm. I don't think I would have detected it with my hand.

HT-18 was able to see the difference easily!

This is my electric water heater.

I have been wanting to add a blanket. Now I can see why I should.

 

 

 

 

 

The ceiling on second floor which has roof on the other side. Outside temperature is around freezing.

This is the HT-18 IR view with the colour code changed to white is cool and black is warm.

I can see the rafters and some of the nails.

Some gaps in the patchy (70 year old?) insulation show as white blobs.

Another part of the second floor ceiling.

I had previously identified this spot with a laser pointer temperature meter and marked spots with tape.

The insulation shows gaps (white blobs) clearly in the HT-18 IR image.

Interestingly, I had added the tape in mid summer, when the roof temperature outside was 60C. This spot was abnormally warmer than most of the ceiling, measuring with a spot beam thermometer. Much easier to see what is going on with HT-18.

A pic of my house from outside at night.

Notice how the basement is the warmest part of the house from outside.

This is probably not good.

This is one of my exterior doors from inside. Temp is -15C outside. I had thought this door was pretty tight. The door looks ok in visible light on the left.

Viewed with IR on the right with white cooler, black warmer mode reveals some problems.

The leaks at the bottom of the door are obvious.

Also the inside structure of the door is visible. This is a cheap hollow door and has cardboard strips glued inside to give the veneer panel some strength. The strips are clearly visible. This door is not a very good insulator.

Just above the waste basket is an electrical outlet which is glowing white. A light switch above it also glows white showing a cold leak.

I have much to learn. This is not a detailed review but a collection of first impressions and images as I learn. I am impressed so far. I think HT-18 will be very useful.

As a footnote, I have another Hti-Xintai instrument, HT-2000 CO2 meter which continues to give good service. I am a satisfied paying customer not a paid reviewer. Web ordering on Hti website, via Amazon or Banggood.

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

INDEX to the series

freezer 3

INDEX to the series

A beautiful sub-zero sunny day.

A perfect day to stack all the frozen food outside while I defrost my freezer.

I'll save a bit of energy and reduce future ice buildup by checking the seal and door hinge adjustment. Easy to do.

Also a good time to inventory what I have on hand and check expiry dates/condition. And clean up a bit of raspberry juice.

The ice build up is all on one end of the freezer. I can see a finger of ice reaching up to where the moist room air has been entering the freezer.

Likely the hinge on the left side of the freezer is a bit too high.

[click any pic to enlarge]

The two hinges hide under plastic covers that snap off if pried gently.

Mine has four Philips head screws holding each hinge.

With the door/cover in the down position, I carefully loosen all eight screws about 1 turn counter clockwise. Because the screws are in slots, the cover is free to move up and down slightly. I could lift the cover off completely if I wanted to.

Instead, I lift each corner slightly and press down slightly to ensure that the cover is sitting evenly all the way around.

The hinges hold the cover securely but should not hold it UP or DOWN from its normal level seated closed position.

Now that I have it in that position, I carefully tighten all the screws alternating between the hinges - one screw on one hinge, the same screw on the other hinge, then the next screw on the first hinge etc.

The final step is to check all around the cover with a piece of paper to ensure that the paper is gripped firmly when the cover is closed.

I did this paper seal test before hinge adjustment and it was apparent to me that the paper was not held well on the left end of the cover. It is now.

Another sign of good freezer health is the vacuum that results when the door is freshly closed. When I open and close the cover now it snaps shut and holds tight. The warm room air trapped in the freezer cools and shrinks. Difficult to open for a few minutes! It did not do that before, at least not like it does now! All good.

While empty, I carefully cleaned and disinfected the seal and door. Some slight mold spots were removed.

The freezer is chilling and will be refilled with sorted frozen food in a couple of hours, kept frozen outside.

I will try to "read" the frost buildup over the next few months to see if I have reduced the seal leak.

Thanks for your interest

George Plhak
Lions Head Ontario Canada

Update June 6, 2020

Ice buildup has started around the left hinge but does not seem to be very severe.

At the right side, there is almost no ice.









INDEX to the series

fixing led string lights 2

Addendum to fixing led string lights.

An example of fuses in a string. Two of the tiny 10mm 3A fuses down in a recess in the plug.

[click any pics to enlarge]

I found it helpful to use a small flat screw driver to push open the tiny cover.

Tiny fast blow 3.0 amp 10mm fuses. You can buy them at Amazon in a larger lot for about 50 cents each. Beautiful laser engraved printing on one end cap.

I've had a chance to look carefully at two strings of more recent (2018 manufacture) from the same company. One has 25 C9 bulbs (top) while the other has 35 C6 bulbs (bottom).

There are significant changes in the strings to what I described previously.

I am sorry to say that the LEDs on both newer strings are NOT REPLACEABLE. I highlighted the corrosion that appeared in the ones I looked at earlier. Apparently the manufacturer has done away with "repair-ability".

Fuses protect from overloads if the user, for example, plugs too many strings together in series. Only the C9 string has fuses in the plug, the C6 string does not. The C9 string came with two spare fuses in a small baggy taped to the plug. Two fuses protect both the line and the neutral since the plug and socket are not polarized.

If either of the two fuses is blown (open circuit) the LED string will not light, nor will another string plugged into it at either the end socket or the feed through socket on the back of the plug. Both are fed by the fuses.

The bulb assemblies of both are masterpieces of precision injection molding. These will not come apart without damage. Probably water tight except for the plug and socket.

The same 3 wire arrangement is used on both newer strings. Two conductors go from plug to socket to carry the line circuit to the next string. The LEDs in the string are all in the third line, down the center if you will. At the plug end, the LEDs connect to the fuse side of the line. At the socket end, the LED string connects to the neutral. Actually, the plug and socket are not polarized, so there is no line and neutral in that sense, but there really is!

There is no canister containing extra parts like resistors or blocking diodes in the newer strings.

Except for the two LEDs nearest the ends, all LEDs have two wires out the bottom. All are in a series string. There is no physical indication of polarity (cathode/anode) on the outside of the bulb assembly, so if you are going to be cutting them out of the string, you'd better mark for orientation or be prepared to test for polarity later.

The end LEDs have three wires coming out the bottom. On each, two of the wires are connected together and to one side of the LED. The third wire is to the rest of the string. The C9 bulb string is pictured.

It is worth noting that at each end, it is the center conductor of the 3 wire LED base that goes to the socket or plug.

Thanks for your interest

George Plhak
Lions Head Ontario Canada

This is an addendum to fixing led string lights.

my typical electrical day winter 2

INDEX to the series

Daylight savings time changed this past weekend.

I normally check my hourly electricity usage at my utility's website to make sure I've reset the water heater timer correctly so that my hot water heater does not come on during peak priced periods. The water heater is a big electricity user here that I can see easily on this chart. Since I have kept it off for twelve hours, it takes a big gulp when it comes back on, when it's cheaper after 7pm. Cheaper by half!

[click any pic to enlarge]

As a single person, I don't use a lot of hot water yet I NEVER run out of scalding hot water during the daytime. Even at 6:45pm after twelve hours OFF (graph of actual water temperature below).

Your mileage may vary. I have a relatively new heater which is a huge improvement over the old one. I am only one, relatively frugal person as a hot water user.

On the Hydro One website (pic above) I can see my water heater coming back ON (biggest bar in the green) yesterday, five minutes after the end of On-Peak pricing. I use a cheap but great timer that does the job perfectly. It is somewhat cryptic to set if you only look at it four times a year. The light is not very good and I need to remember a flashlight.

I did it wrong once and made the situation worse with the heater off for six hours (doing the right thing) and then coming back on in the last hour of peak price, costing me twice as much!

Because my water heater is a wired in appliance running 240 volts, I can't use the sort of web enabled timer/monitor that I was using for smaller plug-in appliances, like the Itead Sonoff S31.

Compare with the daytime winter electrical picture of three plus years ago. At the time, I was using my own smart meter reader which had higher resolution so it looks more jagged. The big spikes (marked W) from the water heater were easily seen. I was trying only a few hours of On-Peak inhibit at the time (marked C). I was also inhibiting the refrigerator and the freezer so the house energy draw drops almost to zero during C.

I'd like to get a web enabled wired-in device for the water heater but I'd still have to check four times a year that it is set correctly. My utility rate changes happen twice a year on a different schedule than the daylight time changes. Four changes per year to check.

Water heater inhibit is a big winner for me as far as savings on my electrical bill. I estimate that the new water heater and the inhibit technique save me between 15-20% on my electricity bill. This is possible because I use less electricity and only off-peak for hot water.

Off peak timing is quite different from lowering the thermostat temperature of the water heater which is actually quite dangerous.

I have the tank thermostat set at the recommended 49C so that Legionnaires’ bacteria are minimized. The tank cools about three degrees after twelve hours off. Returns quickly to the set point at 7pm until the next morning.

Sorry if the graph is difficult to read. It is from the top of my water heater tank today and shows the low temp for the day and the rise to set point.

I'd mentioned my ambition to leave the grid entirely during On-Peak in future.

Thank you for your interest.

George Plhak
Lions Head Ontario Canada

INDEX to the series

battery testing 3

Retesting after 6 months of daily use shows ~10% decline in capacity of my 18650 lithium rechargeable cells.

Last summer I tested three new 2200mAh cells. Initial average capacity was about 2030 mAh with my test which may or may not be accurate. After six months in service, I repeated the test with the same tester and method and found average cell capacity was now about 1822 mAh, or a reduction in capacity of about 10%. Raw data is here.

I attribute the reduction in capacity to my daily usage of the batteries although there could be other causes (* below).

The squiggle (~ tilde) before the 10 means "about" and that is really the theme of this post. Often in amateur science and engineering we need an approximate answer to check a hypothesis or opinion. Some quick measurements, even if approximate, are better than no data at all. Hence the "about". Sometimes repeatability and consistency may be more important than absolute accuracy when we are trying to compare.

In the case of these batteries I had tested for capacity about six months ago. Since then I had used these batteries daily in a vape pipe. They seemed to be performing well. Typically I would switch a battery sometime mid-day putting the partially discharged battery back onto the charger and inserting one of the two other charged batteries into the pipe. So I knew two of the three batteries went through some sort of discharge/charge cycle daily determined by my vaping habit with was pretty steady during the six months. I tried to randomize which battery I did not use each day but wasn't entirely careful about that aspect.

Since I had not used these PKCELL 2200mAh batteries before, I was curious if there was an effect on battery capacity and how much it might be.

Why go to the trouble of testing? I paid about Cdn$15 each for these cells. Some have been junk. I am accumulating things which use 18650 cells and had other applications in mind so I will need to buy more. The best way to determine capacity is to measure with a controlled test.

Initially I had tested each battery three times. Three data points. I like three. With only two measurements, if something goes wrong or varies, it may not be apparent in the data. The two measurements will differ always. With three measurements, hopefully two will be more similar than the one which varied. Ideally all three would cluster tightly. More measurements would be even better but we are after an approximate answer so three is good.

I tested with the same ZHIYU ZB2L3 v2.3a tester and the same 7.5 ohm resistor.

There is a new version 3 of the tester which I have ordered.

[click any pic to enlarge]

I considered changing the load resistor. I am simply using one of the two resistors that came with the kit. Readers will notice that I changed the arrangement of the load for the second round of testing with auto batteries to create a heavier load. I'd like to more closely match the 1C rate that the manufacturer has used for determining the branded 2200mAh rate. But at this point that is less important to me than using the same test and load to compare batteries from different manufacturers or different batches from the same company.

I have recently done initial testing of two new batches of 18650 batteries: four more of the PKCELL 2200mAh and two bright pink Samsung cells, the best I've tested so far! All tests with three repeats each.

Thank you for your interest.

George Plhak
Lions Head, Ontario, Canada

* Other causes - I knew you'd ask. Hypothetical causes really, but possible. Like maybe the batteries have some manufacturing defect that causes them to loose capacity independent of charge/discharge? Or maybe I stored them in a hot car in the sun? I did not, with these batteries, but four similar cells are installed in two emergency flashlights in my cars. Not used at all but subject to some extremes in temperature. I might retest those cells another time.

[The next day] Another possibility why the measurements this time are lower. I had forgotten but was reminded by the photo I used above: I wrote that I was not happy with the battery holder and had ordered a different type. After the new holder arrived, I installed it with shorter, larger gauge wire as you can see in the pic. This is the tester and holder used for this series of tests, on the right.

So it is likely that the resistance of the output load circuit is now less particularly because of the shorter beefier wire. The holder contacts also look more substantial and are well soldered to the wires. Lower load resistance would increase current (the C rate) and reduce mAh measured. Would it be ~10%? I don't know. I should measure! That's the original battery holder and wires to the left.

I won't go back and retest with the thinner wire. But when I retest the latest cells, I will be comparing them to the results from this tester. That's the importance of consistency.

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As is my custom, this is not a paid review nor do I receive or solicit any product in return for writing. I am not selling these products. Just ideas. I don't get a commission. I don't show ads. I don't have a fundraising or patreon page.
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please consider commenting or buying one of my books? Thank you. George

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