HP 200LX >
(on Wikipedia)

Dealing with batteries and other power-related things.

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The main batteries ∞

(AA battery)

Two standard 1.5v AA batteries.

Any kind is acceptable, but only (TODO) are rechargeable in the unit.

Estimated lifespan 10 hours continual use (no pcmcia device / serial / IR use) – software low power warning. HP does not recommend NiHM batteries.

• Alkalines: ~2000 mAh (1.5V)

Lithium flatter discharge curve (high energy lithium batteries can last 35 hours, can work in extreme conditions like voltage spikes/drops and temperature changes)

• NiCd / nicad: 600 – 850, panasonic = 1100 mAh, 1.2V, flatter voltage curve, “memory” — must discharge fully before recharging? (myth!) (rechargable internally)

• NiMH: 1200-1300 mAh, x.xV(?) very flat voltage curve (no memory), self-discharge (not recommended for internal recharge)

Times2Tech NiMH 1500mAh, x.xV(?) very flat voltage curve, very little self-discharge

• The batteries – do they require tips or can they be flat or what??

Alkaline or NiCd main batteries and a LiO button backup cell.

NiMH can supposedly be used, but to recharge them they must be charged once, then charged again (disconnect and reconnect the adapter)internal charge rate is 100mA for fast-mode and 45mA for trickle

HP does not recommend using lithium batteries because of the uneven power drop-off at the end of the battery’s life cycle. This means your Palmtop will show adequate voltage readings until very near the end of the battery’s life, then suddenly drop to inadequate levels. If this happens at a time when you are not using your Palmtop, for example, over a weekend, you could lose your data. A third party product like BATTman from ACE lets you monitor different kinds of batteries including lithiums so you have an adequate warning time.

Lithiums make great spare batteries since they have about a 10-year shelf life, but they make poorer main batteries since they cost about four times the price of alkalines, and last only about three times longer.

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Note that the system can run off of AC power while recharging batteries.

Trivia: The HP 100LX and HP 200LX do not have a digital-to-analog converter and cannot make dial tones. This functionality is instead used to monitor battery charging. This is the only hardware difference between this handheld and a regular computer.

The power adapter ∞

Input: 100 to 240V AV (50 to 60 Hz) – output: 12Vdc 0.75a (DC with a negative tip)

A bare minimum power supply is 300mA, the HP will use 9-15V

One person suggests a power supply of 750mA+, 12V

(remember: underrated voltage will work it harder, heating up the unit and ac adapter)

The 100/200LX does not include an adapter in the box. An optional adapter is available from HP (part # HP F1011A, price: $39.95). The 100/200LX uses 12VDC, negative tip, up to 750mA, approx 5.5mm OD barrel-type connector. The HP adapter is about the size of a deck of playing cards, and comes with fold-away AC prongs. It will take any input voltage from 100 to 240 Volts, at 50/60 Hz, an advantage for world travelers.

A Radio Shack AC adapter (Cat.# 273-1652B) is less expensive and seems to work with the Palmtop. Its only rated at 500mA, so there may be problems when using with high-current PC Cards (i.e., modem cards). It appears to work well while charging NiCds, and current measurements indicate that the 100/200LX draws much less than 500mA with this adapter even when writing to a flash card, charging NiCds, and using the serial port simultaneously.

Note that the system can run off of AC power while recharging batteries.

The backup battery ∞

One 3v cr2032 button cell battery as a memory backup.

Behind the IR panel is a grey tray for the backup battery — if removed harshly, it could tear.

The coin cell backup battery is generally replaced yearly.

There is a software low-power warning which halts the system, beeps and warns the user until they press enter. It prints a message at the top-left in textmodes, or prints nothing in a graphical mode. This message is generally only displayed at powerup. If warned, replace the backup battery immediately!

If you are removing the main batteries, replace them as soon as possible otherwise the backup battery will be drained quickly.

TODO in which orientation does the battery sit?

Power Notes ∞

• The memory state of the operating environment is saved.. so powering it off leaves things perfectly suspended.

• Advanced power management software exists, with notification of low batteries, critically low batteries and backup battery monitoring. Timed auto-shutdown exists, low-battery shutdown exists. Everything is customizable and can be turned off.