On Wed, Nov 2, 2022 at 09:07 AM, Peter Laws wrote:

When I saw the subject, I immediately thought "doesn't that chemistry
create a 4.2-V cell?" And you have answered the question in my head
with "buck circuit". Fine idea, but rarely done without RFI as you
hint at.

Without googling, it goes something like:

Lead-acid - 2 V
Alkaline/carbon-zinc/etc al - 1.5 V
NiCd/NiMH - 1.2 or 1.25 V (I forget!)
Lithium (all variants?) - 4.2 V

I should probably google that ...

Inside there is a tiny cylindrical 4.2V LiIon cell and a small PCB which contains the charging and buck circuit.

The buck component brings the output voltage down to a regulated 1.5V at ~2A max.

The charge circuit expects an input of 4.2V - 5V.

It can be fed either by a USB port mounted on the side of the cell itself, or externally using a dedicated charger.
All that the external charger does is to blindly apply the input voltage.
A traditional LiIon charger would usually not work as it should interpret a cell outputting 1.5V as beyond salvage, and the output voltage would never rise as charging proceeds.

On Wed, Nov 2, 2022 at 7:21 AM Michael Schuster <schuster.ma@...> wrote:

They are unsuitable for use in DXing as the buck circuit produces broadband RFI right inside your radio.

When I saw the subject, I immediately thought "doesn't that chemistry
create a 4.2-V cell?" And you have answered the question in my head
with "buck circuit". Fine idea, but rarely done without RFI as you
hint at.

Without googling, it goes something like:

Lead-acid - 2 V
Alkaline/carbon-zinc/etc al - 1.5 V
NiCd/NiMH - 1.2 or 1.25 V (I forget!)
Lithium (all variants?) - 4.2 V

I should probably google that ...


--
Peter Laws | N5UWY / VE2UWY | plaws plaws net | Travel by Train!

They are unsuitable for use in DXing as the buck circuit produces broadband RFI right inside your radio.

They do work fine for low-current (<2A) voltage sensitive applications where a NiMH cell would prematurely trigger the low voltage alarm, or affect performance (e.g. the motor inside a powered toothbrush).

These promise 3000+mah.

No, they promise 3000 mWh.
That would be 2000 mAh at 1.5V.

Hello,

What do the UL people think of Li ION 1,5 Volt AA batteries?

https://aliexpress.com/premium/li-ion-1%252C5v.html?d=y&origin=y&catId=0&initiative_id=SB_20221102003611&SearchText=li%20ion%201,5v&spm=a2g0o.detail.1000002.0



These promise 3000+mah.

Marc
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