Asus EeePC 900 Battery Life
These are real-world tests. I didn’t use any burning software, but instead did my usual day-to-day work, which involves Gmail, reading via my feedreader (Bloglines Beta), reading up various blogs, and also posting on blogs. And as such, being a real-world test, this involved some pauses in between for bathroom breaks, snacks, and such. And so you would notice a few minutes of “sleep” time in between, where I would close the Eee’s lid to save power.
This was done on an EeePC 900 12GB running (the OEM) Windows XP, updated to SP3. Brightness was at 30%, with WiFi on and audio muted. Note that I had turned off wired LAN in my BIOS, since I didn’t need to get wired, anyway. Camera was also turned off via EeePC tray utility.
Battery is the stock 4-cell battery rated at 7.2V, 5800 mAh.
Here are the results:
2:39 p.m. - Cold boot. Windows usually takes about 30 seconds to launch and another 25 seconds until SSD reads stop.
2:46 p.m. - Sleep. Sudden torrential downpour. And we have laundry hanging outside. And so I had to run out to bring the clothes under cover. Sigh. That’s working at home for you!
Uptime: 7 minutes.
2:59 p.m. - Wake up. Back to work. Am at my desk now, so I’m actually working on my bigger laptop at the same time.
3:31 p.m. - Auto sleep. Read a pretty long email on the bigger laptop, so I somehow left the Eee idle for 5 minuets–which is the idle time I’ve set Windows power management to put the machine to sleep.
Uptime: 32 minutes.
3:39 p.m. - Wake up. It’s a battery test, after all, so I’ve turned the Eee back on again to do some reading up on relevant forums.
4:37 p.m. - Sleep. The Eee actually spent another 5 minutse idle. Damn those long emails.
Uptime: 58 minutes
4:39 - Wake up. 5:55 p.m. - Sleep. No more rain. Brought clothes back out. Not that there’s any sunlight to help dry them faster, but it’s something one has to do.
Uptime: 76 minutes.
6:06 p.m. - Wake up. Battery meter is saying I only have less than an hour left.
6:23 p.m. - Battery LED is flashing LED.
6:32 p.m. - Windows is giving the critical battery alert. I figure I could still do a post, and I publish an article I’ve been writing on Blogging Pro.
6:39 p.m. - Power down.
Uptime: 33 minutes.
And so adding all those uptime minutes, we come to a round sum of 206 minutes. This translates to 3 hours and 26 minutes or roughly 3 and a half hours.
Strangely, that’s exactly how long BatStats estimated the 5800 mAH Asus battery to last.
Asus EeePC 900 Battery Drain Woes
A thread on the EeeUser forum details how some (or most?) EeePC 900 units drain battery even when turned off.
I was just wondering if anyone else has been having this same problem. Now when my eee pc 900 is fully charged and i leave it for a couple of days not using it the battery still drains when even not in use.
And I agree that this is a serious reliability issue. For many people, the Eee serves as a mobile work machine, and for some, as a travel companion. Some just turn on their Eee for a few minutes to check on email and read news, and then off again. But if you lose 10% to 20% of your charge each day then you’d have to plug it in often, which beats the purpose of having a portable computer with a three-plus hours battery life.
I have yet to test this on my machine, but I’m curious to know how Asus will deal with this. Is this perhaps just a BIOS issue? Or is this a battery issue?
Can Solid State Drives Really Help Extend Battery Life?
Extending battery life has been the holy grail of mobile computing. But can solid state hard drives really help?
Recently, the trend is going towards solid-state storage. This means drives that have no moving parts. Most popular of these is flash memory. They’re cheap, durable, and can hold data even without power (unlike volatile RAM, which loses data when power is off). Since flash memory can allegedly reduce consumption caused by spinning hard drives, some manufacturers have switched to using solid state drives for their mobile computers. There are also flash-based hard drives meant for notebook computers that users can replace their existing drives with.
The Asus Eee MyPC sports a flash-based hard drive, instead of a conventional spinning one. One factor may be price (since a small flash drive is cheaper than a micro-sized hard drive with spinning parts). One may be power consumption.
However, a simple test done by ZDnet blogger Robin Harris has rendered results that may run counter to the argument that a solid-state drive helps extend batter life.
The maximum power difference between a flash drive and a 2.5″ disk is 3 watts. If you average about 3 hours battery life, a flash drive would save at most 9 watt hours (wh). That’s 29 minutes with a 55 wh battery. Less than 20 if it isn’t seeking constantly - and less than 10 minutes if the drive spends half its time in standby mode.
The biggest power sink in my notebook is the “everything else” that stays on when nothing is happening - 13 watts. Next is the CPU when it is busy. Then the display if you keep it above minimum brightness, the DVD/CD player and finally, just above Wi-Fi, a busy disk.
Flash drives have a real advantage in shock resistance over disks. But the performance is about the same as a disk, the power savings minimal and the cost disadvantage huge. They make the most sense for premium ultra-light notebooks with low power CPUs and small screens as well as hand-held devices.
I guess I must add that speed is one of the advantages of flash-based storage over a disc-based one. Still, I’d like to get more juice out of my Eee’s battery. Maybe when Asus releases a Pentium-M based Eee that would be better at saving power.
