Está en inglés, por lo que rogaría a algún bilingüe que si le es posible lo resuma en español. Yo sólo intuyo lo que dice realmente, pero creo que esta solución serviría.
La otra pieza fundamental, es Berkus. Seguro que él sabe dónde se compra, o cómo se fabrica un "resistor discharger".
Allá va todo el rollo:
<BLOCKQUOTE><font size="1" face="Verdana, Arial">Comentario:</font><HR> The Inside Story
by Bill Finch, March 8 2001
OK so here's the straight skinny about Lithium ion batteries and storage vs state of charge. To start with, the Lithium technology used by Sony is licensed from a company named AEA (ref 2). AEA
manufactures mil spec batteries for aerospace and the like. Sony has a license for terrestrial use. Camcorder batteries are manufactured by Sony (ref 1) using a lithium oxide cathode and a carbon based
anode. Lithium ions travel through a non aqueous medium during charge and discharge. These batteries have a half life of about 1000 charge cycles (50% charge retained at 1000 charge/discharge cycles).
Lithium batteries retain their state of charge (10% loss per month) much longer than earlier technologies partially because a thin passivating layers forms on the electrode surfaces. (ref 3) The chemical
composition of the passivating layer varies with battery construction chemistry ( a deep dark secret ). The presence of a passivating layer can be problematic if it grows to more completely block the anode and/or cathode. Passivation thickness increases with increased storage time, temperature, and state of charge.
The presence of a passivating layer (essentially a high resistance) always results in a voltage dip from the battery when a load is applied. (see chart in ref 3) The magnitude and period of the dip is a
function of the passivation thickness. The layer thickness is decreased as a function of coulombs transferred from the battery. This layer forms every time you stop using a battery. The layer is removed every time you use the battery.
In Camcorder use if the voltage drop is great enough, the camcorder will shut itself off. This is a normal function in camcorder electronics. If this does happen, the passivation layer can be removed by
putting a pure resistive load on the battery until the passivation layer is removed. Choose a resistance value roughly equivalent to the load normally presented by the camcorder. After a short period the
passivation layer will be completely removed and the battery will then function normally in the camcorder.
Think about these facts until you digest them completely, then never worry again about battery metaphysics.
That's all there is to it.
So, does this mean I'm going to partially discharge my batteries before storage? No Way - too much trouble. It's like paying homage to the old NiCd god. Also this uses up some of the batteries 1000
lives. Armed with this understanding I do have a resistor handy, but so far I have never had to use it over a period of about 3 years.
How to Fix A Lithium Battery
by John Beale 4/11/01
You can attempt to fix an InfoLithium battery which has developed passivation by a process of charging and discharging several times. The TRV900 has a built-in battery charger. When the camera is off,
but plugged into the AC adaptor, and the battery is on it, the battery will be charging (unless it is already fully charged). When the camera is on and not connected to the AC adaptor, it will run off the battery, eventually discharging it to the point where the low-voltage cutout threshold is reached, where it shuts off.
To charge-cycle the battery you:
A) With battery attached to the camera, unplug the AC adaptor from the camera, turn the camera on, and leave it on until it shuts off due to low battery. Note: don't leave it in "camera" mode with a tape in, as it will auto-shutoff after 5 minutes in standby. Instead select "memory" mode, or "VTR" mode, where it will not auto-shutoff until the battery voltage drops. Do not put the camera in a padded case when on, as it will get rather warm.
Having discharged the battery, turn the camera off (leaving the battery attached) and connect AC adaptor. The battery will now charge until it is full.
C) Repeat steps (A) and ( several times.
The above method worked for me with two NP-F330 batteries that had develped passivation due to several months of non-use. If after several tries the battery still dies prematurely, then you have to adopt another method, see below.
Secondary charge-cycle method: resistor load
The TRV900 uses a 7.2 V battery and consumes between 3.9 to 5.2 watts of power depending on operating mode. That implies between 540 mA and 720 mA of current, which would be drawn by a resistor ranging from 13.3 ohms to 10.0 ohms. So, you can simulate this load with a 10 ohm resistor rated to handle at least 5 watts (If possible, I'd suggest 10 W or more). Unless you use a physically
large resistor, after a short time under load the resistor will get very hot and can burn you so be careful. The tricky part is how long to drain the battery with the resistor, as running the battery "flat" may
well do more harm than good.
If the battery is really fully charged, then you should leave the resistor on as long as the "continuous recording time" for the camera drawing that current. A 10-ohm resistor corresponds to using the LCD
screen, and a 13 ohm resistor to using the viewfinder. For example, a charged NP-F330 battery with a 10 ohm resistor load should take 50 minutes to discharge, while the NP-F750 should take 220 minutes. Runtime is listed for all operating modes and battery types in your owner's manual. That page is also online here.
Experience restoring dead NP-F330 battery
by dh sullivan 4/20/01
My infamous battery is finally responding to my efforts. I can happily report that it's up to 45 minutes useful capacity after two applications of the Resistor Discharge method and several follow up
charge/recharge cycles in the camera.
It appears after over a week of experimentation that the resistor method is far more effective than camera discharge/recharging, at least in the case of this battery that was down to 5-7 minutes of useful capacity when I started.
I was ready to prematurely call the resistor method a failure because the benefit was not immediately obvious, but soon realized that each recharging after the initial drain with a 10 ohm/10 watt improved the battery quite dramatically (compared to the very small improvements from vcr mode discharging in the camera)
I decided to see if a second drain with the resistor would offer even greater improvement. It indeed has. My battery continues to improve, and I now plan to regularly rejuvenate my batteries with periodic full discharges with the resistor method.
I have found that the battery should be fully charged before the resistor discharge, and that rather than timing the discharge procedure, I can effectively monitor the progress by simply placing a finger on
the resistor every five minutes or so after the first hour of discharge. The resistor gets very hot initially, but as the battery nears the fully drained state the temperature falls rapidly. I keep the resistor in the battery until it has returned to ambient temperature for about five minutes. I find that after this procedure the battery will show 2-3% charge when I start the recharging process.
I would like to thank John Beale and others who have suggested the basic methodology that got me started. The process has made me a firm believer in fully draining my lithium ion batteries with a resistor periodically.
[note: from the standpoint of best long-term battery life, I would suggest using resistor discharge if and when it seems necessary, rather than as a preventative maintenance step on batteries which do store a full charge. -jpb <HR></BLOCKQUOTE>
Bueno, no se si realmente alguien ha seguido esto hasta el final, pero si es así, seguro que unos cuantos agradeceríamos comentarios al respecto.
Otra cosa... los felices propietarios de "iBook" y "PowerBook G3 Series" (anteriores al modelo "Pismo"), pueden pasar desde su Mac una utilidad llamada "Battery Reset" (disponible en la web de Apple) que seguramente les apañará sus problemas sin tener que recurrir a esto. Por desgracia, en los Pismo no funciona. Doy fe de ello...
Por cierto... sigo comprando una segunda batería para mi PBG3. ¿Alguien la vende?
Este tema ha sido editado por Manolitto: 02 March 2005 - 10:42 PM