[Stoves] TEG geat idea / Li ION recup small idea
Crispin Pemberton-Pigott
crispinpigott at gmail.com
Thu Feb 2 09:54:09 CST 2012
Dear Frans
The charging voltage for a great many laptops is 19-21 volts for a 6 cell
Li-Ion battery.
Is it fair to say that it is safe to charge one cell with 4.2 volts, with an
operating voltage of 3.2?
3.2 is enough to fire most HE-LEDs though many of the packaged units use
3.5 (for full brightness of white HE-LEDs).
19/6 = 3.2 (only) so perhaps 4.2 is a bit high. Are they using a pulse width
modulated chopper to increase it to 25.2 as the charging voltage, or
something else?
I recall some battery packs are charged as 2 parallel sets of 3 in series,
but power is drawn as 6 in series. Those were 12 VDC input. Now they are all
19.2 or so. The one I use has a 9-cell and it is probably 3 sets of 3 in
series when charging.
Breaking out the cells from an old laptop is a safe thing to do and probably
some cells are better than others. In previous discussions here we have
noted that an old (almost dead) cell phone battery can run 3 LEDs for a
couple of weeks. Dead to a phone or laptop is not at all dead to a light,
especially the newest high efficiency small white ones.
Thanks for your continuing advice and enthusiasm.
Regards
Crispin
From: Frans Peeters [mailto:peetersfrans at telenet.be]
Sent: Thursday, February 02, 2012 9:03 AM
To: Stoves
Subject: TEG geat idea / Li ION recup small idea
Dear RON LARSON ,
With KNOW HOW
., a smal idea can become a geat idea for Africa !
The World is over full with LAPTOPS and weak powerpacks !
DELL :It contains 8 Li ION cells of 3,7 volt 3,5Ah
And regulator prints inside -----à secret !!
80% of this broken or wasted packs can be used for head lichts and home
lichting , with 24 LEDS;
you get one week lichted evenings !
You put all the cells in paralel .
And charge by sun with a 10x5 cm sun panel end limit the voltage on 4,2 Volt
like ZX4,2 zener diode
Not more, for explosion danger .
It contaains Fluorinated ether !!!
(For the laesy and fortunated
. :www.CONRAD. de could sell rechargeable
Lithium ION cells ! Not to find in a shop . )
Regards
Frans .
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