Path: ...!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: Jeff Liebermann <jeffl@cruzio.com>
Newsgroups: sci.electronics.design
Subject: Re: Extech EX410A  DVM  Don't Buy
Date: Sat, 05 Oct 2024 17:30:03 -0700
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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/>

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

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

>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.

>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>

>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.

>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.

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

I'm still a kid.  
-- 
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558