On Wed, 27 Feb 2013 16:17:04 -0000, "Ian Field"
wrote:



"John Fields" wrote in message
.. .
On Tue, 26 Feb 2013 21:43:13 -0000, "Ian Field"
wrote:



"John Fields" wrote in message
...
On Tue, 26 Feb 2013 16:46:14 -0000, "Ian Field"
wrote:



"John Fields" wrote in message
om...
On Mon, 25 Feb 2013 22:36:52 -0000, "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Sun, 24 Feb 2013 00:06:18 -0800) it happened Mike
Cook
wrote in
:

A friend has a battery powered Ryobi lawn trimmer ("weed whacker")
which
doesn't work. The 12vdc wall wart puts out only ~ 12.4v.

I charged the lead-acid gel cell using a car charger. The charge
rate
(selectable) was 0.5A. Afterward the trimmer seemed to work as new.

Can the car charger be used to charge this battery? He can install a
timer
to
limit charge time if that's something required.

Thanks.

Old trick was to put a car headlight or some other low voltage bulb
(break
light)
in series as current limiter.
Maybe modern car has only LEDs, dunno, :-)


Its a trick I often use if I have to, but increasingly I turn to the
more
modern electronic/microcontroller type chargers that automatically
switch
to
trickle charge.

---
That's a good thing, since it puts you squarely into the rank of a
"consumer", where you clearly belong, instead of into the ranks of
designers, where you've clearly demonstrated you don't belong.

I could be wrong of course,

Indeed.

---
But, more than likely not, since I requested that you elaborate with
an explanation of your "tricks"

No you didn't (the senility really is robbing your faculties!) The trick
was
already described by someone else - I merely replied I do that too (and
no -
I can't be bothered drawing pictures because you're too thick to
understand).

---
My request was about having you describe the dynamics of a
light-bulb-in-series-with-a-battery current limiter which, no matter
how loudly or how long you squeal excuses about why you can't, you
can't, of course.

The bulb trick isn't that great because of its pronounced PTC
characteristic - as the filament voltage decreases the current doesn't
decrease in due proportion.

I did try to dumb it down for you - I do hope I didn't use too many big
words for you!

---
Posted the same thing twice, huh?

Must be exciting to have some old dude ruffle your feathers to the
point where you don't know whether you're coming or going!

Strange, but that reminds me of an old limerick:

There once was a young man from Kent
whose dick was so long that it bent.
To save him some trouble,
he stuck it in double,
And instead of coming he went.

Certainly a problem you'll never have to contend with.

--
JF