Battery Life
Battery Life
Intro
One problem that currently plagues PocketPC's is battery life, i.e. autonomy, in every day use. As you can well imagine, this problem is made worse by the adjunction of hardware with its own power supply requirements, memory cards, Bluetooth cards, 802.11b cards and...GPS receivers. This page will focus on battery life requirements of the various GPS hardware solutions. Tests were made with an iPaq 3670 that has 950mAh Lithium-Ion battery. Current iPaq PDAs (38xx and 39xx) have a 1,400mah battery and it's rumored that the upcoming iPaq 5000 will have a 2,100mAh battery. The Fujitsu Loox has a 1,500mAh battery.
Update: I have had access to on iPaq 3975 and other than its fabulous screen it also has a much improved battery life. I don't know if it's because it's a brand new model but battery performance was quite stunning. Not only did it give more minutes of use per % (2.18' vs 1.16') but it also was able to power the CF GPS until it indicated a 0% battery level.
The current trend is for chips with lower power
requirements and it has allowed the introduction of GPS hardware in the new
and more portable CF (Compact Flash) form factor. While this form factor is
rather appealing, you should keep in mind that it will severely reduce the
already limited autonomy of your PDA as shown below.
If you need a cheap power boost, you can use a "battery extender" using 4 AA
Nimh rechargeable batteries. These extenders cost about
$10 and will work with most
PDAs out there (iPaq 36xx/37xx, iPaq 38xx/39xx with the
standard
adapter, Toshiba e310/e570/e550g, e740, Fujitsu Loox,
let me know about
others)
Test methodology
Let me first state that his test has no scientific pretensions and is only here to hopefully give you an idea of "real life" usage:
 | I used my trusty iPaq 3670 with its 950mAh battery and dual CF jacket by Pitech |
| I used PowerLoc's Destinator in a stationery position and calculated one 53 mile route |
| To measure battery life, I used the excellent Battery Monitor by Pdawin.com |
| I put the backlight at 50% and 0%. I think the 0% backlight is a reasonable assumption given that most PocketPC's are very legible outdoors without any backlight thanks to their reflective/transflective screens |
| Timings were done once as there was no real reason for fluctuation |
| I made sure the GPS had a position fix at all moments |
| Reported times down until the unit powered off |
| Note that one could probably play with the SiRF chipset Trickle modes but it's not something a normal user would do so this was not tested here |
Results
| Battery Test | |||||||
| Model | Chipset |
Portability *** |
Rated Power draw |
Battery life test 50% backlight before power off |
Battery life test 0% backlight before power off |
Powered off at 50% BL/0% BL |
Notes |
| PocketMap CF GPS | SiRF IIe | B | 160mA | 48' | 103' | 50%/40% | Wasn't able to achieve a lower "power-off" number without backlight. |
| Emtac Bluetooth GPS | SiRF IIe/LP | A | 80mA | 117' | 236' | 40%/20% | Connected to the iPaq via the the
Socketcom BT CF adapter Built in Lithium-Ion battery keeps it going after your PPC "dies" ! |
| Billionton CF GPS | SiRF IIe | B+ | 160mW | 71' | 98' | 50%/30% | For some reason did better with backlight on. |
| Transplant CF GPS | SiRF IIe | B | 160mW | 58'/210' * | 130' | 50%/20%/0% | Better performance than the PocketMap CF GPS |
| Navman Sleeve | SiRF IIe | B | 160mW | 56'/236' * | 91' | 40%/30%/0% | On par with the "bulky" CF GPS
receivers with the backlight on Not quite as good with the BL off |
| Holux CF GPS | SiRF IIe/LP | B | 80mA | 98'/286' * | 180' | 20%/20% | An impressive performance that proves that the LP in IIe/LP does mean Low Power ! |
| Pretec CF LP GPS | Trimble | B | 40mA | 79' | - | 50% | Not terribly impressive for a "Low Power" chipset. It's probably due to the fact that it's a "SoftGPS" of sorts, i.e. that it uses the PocketPCs processor power to operate. |
| Fortuna PocketTrack | SiRF IIe | B | 160mA | 60' | 94' | 40%50% | Good performance for a SiRF IIe GPS with good sensivity |
| New CoPilot Sleeve | SiRF IIe/LP | B | 90mA | 76' | 189' | 30%/30% | Excellent performance thanks to the IIe/LP chipset. Not quite as good as the Holux with BL on for some reason. |
| * Results in blue indicate testing with an iPaq 3975. | |||||||
