External Battery Roundup: Stay Away From The Wall Socket

Amstron MedXP 140 And 300

First up, we have the MedXP 140 and 300 from Amstron. These two models are the upper-end of the company's external battery lineup. There is a MedXP 66, but this wasn't available to us for testing. These are the two heaviest batteries in our roundup, and that heft is each to see in their durable construction.

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The MedXP 140 is encased in aluminum with a rubber bumper. Comparatively, the behemoth-sized MedXP 300 is encased in a very thick ~1/8" shell of what seems to be ABS plastic. Both come with a full set of tips for a wide range of laptop vendors. However, only the MedXP 300 has a USB port for charging smaller devices.

These two external batteries are intended for industrial applications, particularly in the medical field. Amstron envisions its products placed on medical carts to drive mobile computers, which hospital staff can use to interact with other medical equipment.

Because of the large capacity of its batteries, Amstron provides beefy AC adapters to charge them.

Using these devices is easy. Just select the correct tip and you're good to go. The only major complaint we have is that the angled plug on the MedXP 140 makes it hard to charge without removing the output cable. The MedXP 300's charger plug is on the other side of the unit, so there is no plug conflict. Ideally, both batteries would have an off state, but this only exists on the MedXP 300.

  • lashabane
    Excellent article. I had an idea that this stuff was out there but never really bothered to look. If the 4-5 hours I get from my Asus 1215t begins to not cut it, I now know where to look. Thanks!
    Reply
  • zodiacfml
    I did not understood any of the technical reading especially the part about the desktop PSU.
    At one point, it is stated that AC adapters have higher voltage than the battery on a notebook so that it can be charged. Then, how can a external battery damage a notebook's electronics with a higher voltage (only if it's too high)?

    It is not stated how to set the external battery voltage correctly. What then is the correct voltage? Correct me but I believe the voltage has to be equal that of notebook battery.
    Reply
  • burnley14
    It's pretty remarkable that after page 2 I could guess who the author of this article was (without looking of course) due to the thoroughness and good grammar/lack of typos. Hats off to you yet again, Mr. Ku. Job well done as always.
    Reply
  • @zodiacfml

    it's simple really, AC adapter spit out AC, Batteries spit out DC
    Reply
  • nukemaster
    zodiacfmlI did not understood any of the technical reading especially the part about the desktop PSU.At one point, it is stated that AC adapters have higher voltage than the battery on a notebook so that it can be charged. Then, how can a external battery damage a notebook's electronics with a higher voltage (only if it's too high)? It is not stated how to set the external battery voltage correctly. What then is the correct voltage? Correct me but I believe the voltage has to be equal that of notebook battery.Your guess is actually right. The battery with its voltage set too high can damage the notebook.
    If you need to know the voltage required, you just check on your laptop AC adapter or power brick. It is not always the same as the battery.

    For instance, a Compaq R3000 has an 18.5 volt AC->DC(120w) power supply and its battery is only 14.5 volts. The voltage regulators in the laptop(in the charging system) it self cut it down to the needed 14.5-15volts to charge the battery.

    Also note that the AC adapter does NOT spit out AC it in fact spits out DC(it has a rectifier to convert AC to DC).

    As you can see by this picture(you have to click the link), The adapter takes in AC 120V and spits out DC 18.5V. AC is shown with a ~ and DC with a --_---_-- cant make it on here, but you get the point.
    http://img269.imageshack.us/img269/1950/powerw.jpg
    Reply
  • Onus
    Thanks for the comments on Digipower. I've placed them on my personal "Do Not Buy" list.
    Reply
  • Luscious
    Quite a different experience on my end testing the Energizer XP8000 and XP18000.

    For my smartphone and MiFi, the XP8000 just can't be beat. 5x runtime guarantees me 20+ hours of 3G broadband and week-long phone use. Being barely bigger than a Blackberry, I can effortlessly stash the XP8000 on my belt, and charge my smartphone while I walk.

    The XP18000, on the other hand, was a huge disappointment. Using a Toshiba NB305 netbook, it was incapable of recharging the factory 6-cell battery while powered on, and could not provide 2 full charges while powered off. For my usage scenario, that's a failure, as I plug in the external battery when my netbook hits 3% critical, right before Windows does a force shutdown, allowing me to continue working.

    Using this deplete-charge-deplete approach SHOULD allow me 14+ hours of continuous power-on time, except that even the beefy XP18000 couldn't get through 1 netbook charge. Had it been capable of providing one full charge powered on, or two full charges powered off, I would have recommended the XP18000 as well.

    http://lgponthemove.blogspot.com/2010/07/accessory-corner-3-energizer-xp18000.html
    Reply
  • a_fortiori
    Nice article. I wonder if these units can be used as a mini-ups for equipment like a NAS, routers and modems. It would be great if you could wire these with the NAS, and be sure that a power outage wouldn't damage the NAS. Considering that the NAS units typically consume much less power than a notebook, these should be able to cover 4-5 hrs of power outage (?) Any thoughts?
    Reply
  • shineon2010
    Very good info , alot of products that im having second thoughts about.
    Reply
  • junixophobia
    shineon2010Very good info , alot of products that im having second thoughts about.
    Just buy an automatic inverter that works for hours with a car battery
    Reply