On Fri, 30 Apr 2021 08:42:58 -0400, Moshe Braner wrote:

On 4/30/2021 6:01 AM, Martin Gregorie wrote:

Right in theory, but in reality it seems that many of those
push-button-to-start devices hold their charge for many months, even
years, with no problem. I have several such devices, including rarely
used old smartphones and tablets, e-readers, goTenna gizmos,
flashlights, etc. The circuit of such on/off buttons can be designed to
use mere microamps *.

I was quoting from my own experience from using apparently similar PNAs:
one has a mechanical power switch, the other a soft sensor power switch.
But I take your point: an even old Pentax Optio snapper uses a soft
switch, but holds charge much better than the newer Medion PNA I run
LK8000 on.

And I've read warnings in various places NOT to use a "float" charger on
lithium batteries.

I was not recommending using an SLA charger for Li-ion or LiPO batteries.
Maybe I should have been clearer about that.

This could well be a case for recommending devices that charge via a USB
connector - I don't recall seeing any of these that don't stop accepting
charge when its battery is full.

* Math appendix: if the battery capacity is 1 amp-hour and the
pushbutton circuit uses 10 microamps it will take 100,000 hours to
discharge the battery. That is more than 10 years.

Sure, but in a race to the bottom on competitive pricing, what's the
likelihood that the device will contain the best soft switch rather than
the cheapest?



--
Martin | martin at
Gregorie | gregorie dot org