External Battery Roundup: Stay Away From The Wall Socket

Electrovaya PowerPad 95 And 130

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fuel gauge recently underwent a firmware revision, which is why the information on Electrovaya’s Web site is slightly out of date.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.

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  • sylvain
    Interesting read. Would it be possible to do a similar test for pure USB external batteries. Used for adding that extra bit of juice to an iPad, iPhone or similar devices?
  • Anonymous

    I am interested in using the battery for a DSLR video rig, i want to use the 12v to power the camera, then split the 5v to power both an asus wicast and a SDI to HDMI down convertor. both these last two devices take a 5v feed. would this be possible do you think?
  • Spanamana
    I purchased one of these batteries from a UK supplier and have to say I have never encountered such poor customer service in a long time. They claim that they supply one free tip a year. Rubbish! When you try to get one for a iPad 3 or later, they charge you $10 because they changed the name of it from "tip".

    After 8 months the battery started not keeping its charge. I tried to use the 2 year warranty to get it replaced and found out that although the unit is guaranteed for two years, the battery is only guaranteed for 6 months. Then I was told that it would cost too much to get it repaired as there is no UK repair centre and therefore there is a charge of $30 for a replacement.

    Having delivered the replacement battery, I have not received a VAT order for £21 for import duty from TNT. So a battery that cost me £50 has now cost me £95.

    Shonky product, useless service. Don't waste your money.