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TA-t3 is offline TA-t3
2008-10-21 , 14:53
Posts: 3,841 | Thanked: 1,079 times | Joined on Nov 2006
#77
Originally Posted by xxM5xx View Post
I have a question. Does the safety circuit in your PALM PDA battery only do under and over voltage, or is there a control of discharge current. Reason I ask is that externally shorting Lithium Ion or Lithium Polymer is dangerous.
I don't remember if it trips on short circuiting (or other overcharging), unfortunately. It's been a couple of years since I did the mod and since I followed the Brighthand discussion.

But there is some info over at batteryuniversity.com.
Scroll down a little bit on http://batteryuniversity.com/partone-10.htm
and it describes a lithium-ion battery protection circuit that trips on 4.30V, 2.5V, and it has indirect over-current tripper in that a separate fuse opens at 90 degrees C (194 F) - the battery gets hot very quickly if you short it.
That article is from 2006 (last update), so it was highly up-to-date when I did my battery mod. I don't think much has changed in this respect since then.

EDIT: Added:
Very good. So there is a circuit board. This means it is best not to expose it to 100% humidity.
Agreed. Here is some info cut&past'ed from a battery reseller - a lot of them seem to have included more-or-less the same advice:
[G]uidelines to reduce age-related capacity losses and how to prime new and stored PALM TUNGSTEN T3 batteries:
1.Keep PALM TUNGSTEN T3 batteries in a cool and dry storage area. Refrigeration is recommended but freezers should be avoided. When refrigerated, the battery should be placed in a plastic bag to protect against condensation.
2.Do not store lithium-ion battery fully depleted. If empty, charge for about 30 minutes before storage. Self-discharge on a depleted battery may cause the protection circuit to trip, preventing a recharge.
3.Do not fully charge lithium and nickel-based batteries before storage. Keep them partially charged and apply a full charge before use. Store lithium-ion at about 40% state-of-charge (3.75-3.80V/cell open terminal).
4.Do not stockpile lithium-ion batteries; avoid buying dated stock,Observe the manufacturing date, if available.
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Last edited by TA-t3; 2008-11-24 at 12:47. Reason: Added the last part. Later fixed some typos.