Re: Best/Cheapest GPS with Auto Routing

From: Hans-Georg Michna (hans-georgNoEmailPlease_at_michna.com)
Date: 08/01/04 

Date: Sun, 01 Aug 2004 09:46:23 +0200

On Sat, 31 Jul 2004 15:47:32 GMT, "HH" <htrinh@hotmail.com>
wrote:

>"Hans-Georg Michna" <hans-georgNoEmailPlease@michna.com> wrote in message
>news:gc6ng0hs3emtrneacimn5ot6ticucpiib1@4ax.com...

>> my experience with Lithium rechargeables is very good. I do some
>> maintenance on them though, perhaps that helps. What I do is
>> this.
>>
>> When I first get the battery or the device, I charge it fully,
>> then discharge it fully, then charge it fully once more.
>>
>> At least once every half year I discharge each battery fully,
>> then recharge it fully.

>Do you know that there is a minimum voltage that the Li-Ion cell needs to be
>above? Once that the voltage goes below that minimum voltage, there is
>permanent damage to the cell. If I remember correctly, it's 2.9v.

Yes, I know that very well. It is the reason why Lithium
rechargeables have electronics built in that prevent a deep
discharge. I rely on these electronics.

>Then some manufacturers actually reach that voltage and there is minor
>damage to the cell. One of the examples is the Canon G2 (digital camera).
>Then they came out with a new firmware that has a higher cut-off voltage.
>However, it's too late for one of my friend. He used to fully discharge his
>battery thinking that Li-On have memory like the old Ni-Cd battery.

That's a defect. Defects have to be repaired.

>So for me, I don't do a full discharge on my Li-Ion, I usually discharge it
>down to about 10% then recharge it.

My experience indicates that the problem with too deep
discharges may be rare.

One way to make it even rarer is to stop discharging already
when the device switches itself off the first time. I usually
went even further and switched it on a second time, even a
third, until it stays on only for a few seconds. Maybe that is
unwise, but it still didn't do any obvious harm to any of my
Lithium rechargeable batteries. This only shows that the problem
does not exist in my cases.

Hans-Georg 

-- 
No mail, please.

Relevant Pages

  • Re: High-capacity NiMH cells -- very rapid self-discharge common?
    ... discharge is. ... still charge to 1.35-4, it could be the camera, but Sanyo, Panasonic, ... and the battery packs came already made up, ... (Common NiMHs, 2000 mAh, not Eneloops). ...
    (rec.photo.digital)
  • Re: High-capacity NiMH cells -- very rapid self-discharge common?
    ... discharge is. ... still charge to 1.35-4, it could be the camera, but Sanyo, Panasonic, ... and the battery packs came already made up, ... (Common NiMHs, 2000 mAh, not Eneloops). ...
    (rec.photo.digital)
  • Re: charging a fully discharged car lead acid battery
    ... >> alternator to charge it up. ... A discharged battery will read around ... >> indicated that it was in a deep discharge state, ... charger overnight and check the open circuit voltage in the morning. ...
    (sci.electronics.repair)
  • Re: Shutdown my Laptop? Why should I?
    ... The end effect may be similar in terms of degraded performance, ... to completely discharge these batteries on occasion to avoid this. ... The integrated circuits may get out of sync with the battery (usually when the ... Now the battery will charge, ...
    (Debian-User)
  • Re: Shutdown my Laptop? Why should I?
    ... memory, they just lose capacity each time they're charged. ... the material 'remembers' it's charged state and won't discharge. ... The integrated circuits may get out of sync with the battery (usually when ... Now the battery will charge, ...
    (Debian-User)