Electrovaya and APC were the two of the first companies to make external batteries. While APC has since discontinued the Universal Notebook Battery, Electrovaya still considers external batteries a staple business product, and counts hospitals and IT staff among its most frequent customers.
There are only two battery models: the PowerPad 95 and 130, named after their watt-hour ratings. Encased in a thick shell of hard ABS plastic, the PowerPad's batteries can take a fair deal of punishment.
Electrovaya uses a propriety lithium-ion chemistry called lithium-ion SuperPolymer, which claims a longer battery life than the typical lithium-lon seen in your notebook.
Electrovaya tells us it hasn't dropped the PowerPad 95 from its line-up. But that unit has been out of stock much longer than the 130, so we hope this is just a short-term supply problem. Both products have two USB ports to charge your cell phone and other peripherals, along with a LCD that shows the current status of the battery.
The fuel gauge recently underwent a firmware revision, which is why the information on Electrovaya’s Web site is slightly out of date. Previously, the fuel gauge was a digital counter.
The company switched to an icon, which sections off the remaining charge in 20% increments. We asked Electrovaya to explain the change, and it cited an updated firmware that includes further power saving enhancements. These improvements added enough code that Electrovaya was required to remove existing portions of the old firmware to fit it on the same ROM. Personally, the digital counter was one of the things I loved about the PowerPads, so it's disappointing to see that feature removed. It is our hope that Electrovaya physically implements a larger memory chip moving forward so we don’t have to give up one benefit to get another.
Most batteries have no easy way to check degradation (the ability to hold a charge). The PowerPads cleverly show this information under SoH or “State of Health.” This small line tells you how much of the originally battery life you can still reach. For example, if you were originally getting 10 hours and now are getting 9 hours, the meter would read 90%.
Using a PowerPad is easy. The single button under the LCD is more than just an On/Off switch. Once you plug in a tip, the sense resistor has a feedback loop that causes a processor in the PowerPad to recognize the voltage. You must press the button on the confirmation screen in order for the battery to start outputting current. This is Electrovaya’s second line of defence to prevent damage.
Most batteries require their own charger, but PowerPads can use the same charger as your notebook. How can that be? Because different notebooks charge at different voltages, so do the PowerPads. They use sense resistors on the input side as well as the output side. So, what happens if you use a 16 V input tip and a 19 V output? In that case, you charge the PowerPad battery, but you can't output power to the notebook. This is a safety mechanism that Electrovaya implemented to prevent electrical failure. The entire circuit must operate on the same voltage or power output will be disabled.
The above picture showcases the entire input/output tip set. However, PowerPads are the only batteries included in our roundup that don't include a starter set of tips. Each input/output tip runs $10. You get a discount for buying the whole set, but you probably won't need that wide range of compatibility options unless you are in an IT department.
- Staying Mobile Longer
- The Contenders: Specifications
- Background: The Technical Stuff
- External Batteries: How Do They Work?
- Amstron MedXP 140 And 300
- Brunton Sustain And Impel
- Digipower Universal Notebook Battery (EBP-NB60)
- Electrovaya PowerPad 95 And 130
- Energizer XP8000 And XP18000
- Lenmar PPU916
- PowerTraveller PowerGorilla And MiniGorilla
- Tekkeon myPower ALL Plus MP3750, MP3450, MP3450i
- MikeGyver: The Mac Solution
- Test Setup
- Benchmark Results: Netbook Battery Life
- Benchmark Results: Notebook Battery Life
- Benchmark Results: Recharge
- Feature Checklist
- Final Words