Acer 3810T + Xpal/energizer XP8000 external battery ?

[eva2000]

I just purchased an Energizer / XPAL XP8000 external battery Energizer® XP8000 Portable Charger for Netbooks and More!

It's rated output at

• 5V = 1000mA
• DC12V = 2000mA
• DC19V = 2000mA
• 30WH Max

Now my Acer 3810T power adapter output is rated at 19V = 3.42A and battery is 5800mah 63w at 10.8v.

So

1. What's the correct formula for calculating how much extra battery time (%), the XP8000 will add to my unit ?
   
2. Does this mean the Acer 3810T power adapter charges at 1.71x times the rate of the XP8000 3.42A/2A at DC19V ?
   
3. Does this mean 30WH max XP8000 rating, mean 30/63 = 47.6% extra battery life ?

Thanks

[michael_recycled]

Hi,

your built-in battery has a theoretical capacity of 63 Wh. This value is theory since you can usually make use of 85~90% of the capacity. Plus aging will decrease the capacity of your battery further.

Assuming you have a perfectly new battery, you simply have to put the 30 Wh capacity of your external battery into relation with your built-in battery (63 Wh).
That makes roughly 50% more capacity. Your assumption in Q3 is correct.

BUT: This external battery is connected to your PSU plug. Your operating system then thinks, it is connected to AC and (depending on power management settings) will switch to a more energy-hungry power plan.

Q2: The amperages stated for both batteries determine the maximum load the battery is specified to handle. Your internal battery survives a peak load of 65 W, whereas the addon battery is designed to handle 38W max. only.
This all is totally unrelated to the charging process. (According to the manual, the charging time you the external battery is 3~4 hours.)

Michael