Re: Extech EX410A DVM Don't Buy

On a sunny day (Sat, 05 Oct 2024 17:30:03 -0700) it happened Jeff Liebermann
<jeffl@cruzio.com> wrote in <ugj3gjp918lmu1b7fipb2vqe4a2kucgf5q@4ax.com>:

On Sat, 05 Oct 2024 14:37:55 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
(chomp)

I remember the Wellers from work, had one for years at home too.

>
I remember and like the reassuring clicking sound of the "magnastat"
contacts.  If I don't hear the clicking, I know something is seriously
wrong (such as the contacts welded together).
>

As to rechargable AAA and AA I use 'Eneloop' batteries,
self discharge is almost zero, nice in a small flashlight (always light even if not used in ages)
in TV remotes, even in my gamma spectrometer.

>
NiMH generally work well in devices that will tolerate low voltages.
Eneloop cells start out at about 1.5V and expected to work down to
1.2V.  Most of the meters and gadgets fail at 1.3V and below.  My
guess(tm) is that the meter starts to complain that it wants a charge
when about 40% of the capacity is still left in the battery.  Most of
the equipment I've seen is designed to use alkaline cells which has a
higher voltage range.
>
There are also consistence problems and matching issues with NiMH:
<https://eneloop101.com/batteries/eneloop-test-results/>

Wow, some test site.
Eneloop looks good, oldest onces I have are AAA from 2010 ...
still going fine, some in remotes, one in an inside/outside temperature meter

I have a DCF radio-clock with eneloop too.

Fun with shorting alakline batteries:
<https://www.learnbydestroying.com/jeffl/pics/Duracell/index.html>

I gave up on Duracell long ago, when the AA rechargebles I bought for a lot of money
did not keepd their charge even for a few days!
I still have those, repeated test once .. some result.. crap.

I have some AA lifepo4 and a 250 Ah big 12V lifepo4 pack with a 2 kW 50 Hz DC/ AC converter
that can power my fridge or even a cooking plate or a microwave if needed.
https://panteltje.online/pub/250_Ah_12V_to_230V_sinewave_IXXIMG_0796.JPG
Flexible solar cells I can lay out in the garden... and a charger for the battery pack.

>
I have a gasoline generator for running my two refrigerators.  I tried
using batteries and an inverter, but they couldn't tolerate the
required peak surge current of the refrigerators.  Generators are also
useful for drying my gloves.
<https://photos.app.goo.gl/WDezqtWsXkfubmdJ8>

Yes, that is nice

No generator here, but I am considering buying something like this:
 https://tesup.com/uk/tesup-vertical-wind-turbines-for-homes
there is more wind than sun here :-)

I have two LiFePO4 batteries:
<https://www.bioennopower.com/products/12v-20ah-lfp-battery>

That is very expensive,
I payed $872.14 for my 12 V Lifepo4 250 Ah battery pack from Aliexpress.

I plan to use them in running my networking and media (TV) equipment,
which I'm slowly converting to run on 12V DC power.  I live in the
deep dark forest, where solar power is not practical.  I do have a 160
watt panel that works for a few hours during summer and doesn't work
at all during winter.

Well, I am more lucky with a huge garden where the wind can blow,
A wind generator on the roof would produce a LOT of power here,
but might blow away in the next storm, we just had one.
But in the garden, why not?
Can you not mount something on top of an old tree?

I do use a lipo in my weather station, one 3V lipo + a short (Ohm) AAA battery
to replace 2 1.5 V batteries, same in one remote.

>
Ok, that works.  My problem with do-it-thyself battery power systems
is they usually are missing the BMS (battery management system).  A
BMS is mandatory for Lithium-Anything system.
>

The weather station runs a few month on that before it needs a re-charge.

>
I solved that problem a few years ago by convincing a neighbor to buy
a "no moving parts" weather station for about $300.
<https://tempestwx.com/station/76665/grid>
<https://shop.tempest.earth/products/tempest>
I get to play with it and he gets to deal with maintenance issues.

Better than mine, mine only does temperature and humidity, sends data via RF to an in-house receiver.
I also log it to a file, receive it with an RTL-SDR stick connected to a Raspberry Pi.
I have been experimenting with wind speed - and direction sensors based on temperature differences:
 https://panteltje.nl/panteltje/pic/wind_pic_thermal_udp/
and by using ultrasonics:
 https://panteltje.nl/pub/wind_speed_by_differential_2_ebay_distance_meters_IMG_4891.JPG
  these are 2 dolar ultrasonic distance meters from ebay..

The remote I do not remember having recharged in a few years...

>
I have a bad habit called "YouTube".  Google allows free streaming on
YouTube, but adds an overdose of commercials.  The commercials are
tolerable because Google allows me to skip forward with the touch of a
button on the remote control.  Unfortunately, my remote is by Roku,
which is not very well constructed, and with the upcoming election,
the number of commercial interruptions have grown substantially.  I
haven't counted, but I would guess(tm) that I need to push the same
remote button 100 times per day.  The average life of my remote
control buttons is about 3 months.  A remote doesn't last long enough
for me to worry about charging.  I stuff in whatever AAA alkaline
cells I can find and use the remote until it dies.
<https://www.roku.com/products/accessories>

Interesting thing, just bought a new Samsung TV a few month ago,
its remote works on RF, not IR, and it has a solar cell and a build in fixed rechargable battery....
The remote works even from an other room, no need to point it at the TV either, very small,
very few buttons... controls menus on the screen.
 https://www.samsung.com/levant/tvs/smart-tv/one-remote/
seems it can learn IR commands too? have not tried that.

And have several lipo 2 and 3 cell models for my drones:
https://panteltje.nl/pub/3cell_40C_ebay_lipo_IMG_6682.JPG

>
I have 2 drones.  I haven't flown either drone for about 6 years.
Flying a drone in the trees is a really bad idea.  Also, the county
government and FCC have various restrictions that make legal drone
flying without a commercial license almost impossible.  For
entertainment I've become rather adept at indoor drone flying.  I
can't find any photos.  Remind me to take some photos if you're
interested.

Well, I did some testing writing quadcopter code, these days useful for bombing I guess:
 https://panteltje.nl/panteltje/quadcopter/index.html
but now I am close to a mil airport, and drone flying is forbidden here...
I have a bigger delta wing drone too:
 https://panteltje.nl/pub/axion_laser_arrow_in_open_box_IMG_3799.GIF

And ofcourse many of these in different projects:
https://panteltje.nl/pub/SWR_bridge_wired_IMG_5013.JPG
https://panteltje.online/pub/SWR_bridge_on_dummy_load_IMG_5046.JPG

>
I'll pretend to be polite and not say anything about the wiring.

Ah, how 'bout this then?
 https://panteltje.nl/pub/z80/sound_card_bottom.jpg

As a kid I started with 4.5 V batteries...

>
I'm still a kid. 

Sure, almost 80 here ...

I am still running around, biking, writing code and soldering with 60/40.
lead bad?
;-)
Inhaled resin smoke all my life,

BTW that Voltcraft soldering iron has adjustable preset temperatures,
so no special tips needed like a Weller.
Also I >never use a wet sponge< on the tips,
I clean tips with a piece of kleenex or even toilet paper, or rub it against the lead..
Using wet sponges kills your soldering tips, it is a sales trick.
I have tips that still look fine after 24 years.