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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These promise 3000+mah.

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

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).

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 ...


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

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.