Thinkpads Forum

I'm looking for an external ThinkPad battery charger that has recondition/reset option in it - to charge recharge battery several times

Does anyone know of one, besides 1 - 2 Lenovo offers (they don't seem to have that reset option, they are just chargers)

For example, if you have Apple laptop, you can use this nice gadget:
http://www.newertech.com/products/charger_cond.php

Anything like this, but for a ThinkPad?

I've never heard it said that lithium batteries (which the Tpads use) need "reconditioning". They don't gain anything from being discharged and recharged, they don't suffer from the old NiCad "memory effect". Neither should NiMh cells, or any NiCads from companies using newer technologies.

Power manager has "Gauge Reset" option in it.

I would want something similar to that feature, but in an external charger.

As I understand it, a "gauge reset" is changing your software--not the battery. You are changing your battery monitor software to tell it "This battery is at 100% capacity when it reads 10 volts, it will never resach 10.5 again".

So the software is being recalibrated to the new lower capacity of the aging battery. The battery is not being reconditioned in any way. Big difference.

well it's not really the software in the PC but the firmware in the battery. There is a circuit board there and that's where Windows (and any applications) get it's information from. The software (firmware) is what gets calibrated.

I wouldn't buy any (i doubt they are available). To calibrate the battery the software allows the system to drain to a safe level (think about 10% of actual). Then starts charging it again till "full" and then does that once more. Any charger out there could drain the power but where would it go? There's nothing using the power to drain the battery.

EDIT - hellosailor means mAHs instead of voltages Even when the battery only lasts for 2 mins it still delivers 12volts but its lost it's wattage/amps that keeps it going at that power for more than 2 minutes.

SHoTTa35 wrote:Any charger out there could drain the power but where would it go?

Heat .

SHoTTa35 wrote:There's nothing using the power to drain the battery.

A 5 ohm, 20 watt resistor (or equivalent electronic circuit) would be effective in draining a fully charged battery in a couple of hours.

Shott-
No, I meant voltage, not milliamphours. As the capacity decreases in a rechargeable cell (of whatever chemistry) the max cell voltage also drops. While it is always more accurate to actually measure amp-hours, you can get a reasonably good approximation of battery condition by reading the battery voltage under known circumstances. Charge state, rate of discharge, yes, there are more complicating factors but if you fully charge a battery (by simple timed charge) and let it rest, then measure the voltage, you get a reasonably fast accurate picture of the battery capacity.
In 12v lead acid batteries this breaks down neatly into 1/10th volt per 10% charge capacity. In other stacks with other chemistries, it will vary.
Yes, there's charging circuitry (a computer of sorts) in the laptop battery packs--but the ones I know don't track battery capacity at all. They track charging current to each set of cells (sets, in a series/parallel array) and cutoff peak amperage and peak voltage. The computer's power management software is left to track the "asset number", an internal serial number, of the battery pack, and then to keep other data along with that asset number. The data can include anything that is relevant, i.e. how much capacity the battery pack last showed. And because that is static data from a static table made in the past--you need to recalibrate the software table in the computer, not in the battery. All you are doing is testing the battery's capacity, and then storing that number in a file. In the power management software in your computer.

At least, that's the way other manufacturers are doing it.
"For sure".<G>

Take away their hardware-specific power management software? And the battery and OS both know nothing about capacity.