# External Battery Roundup: Stay Away From The Wall Socket

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#### lashabane

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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!

#### zodiacfml

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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.

#### burnley14

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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.

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#### Guest

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@zodiacfml

it's simple really, AC adapter spit out AC, Batteries spit out DC

#### nukemaster

##### Titan
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[citation][nom]zodiacfml[/nom]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.[/citation]
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

#### Onus

##### Titan
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Thanks for the comments on Digipower. I've placed them on my personal "Do Not Buy" list.

#### Luscious

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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

#### a_fortiori

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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?

#### shineon2010

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Very good info , alot of products that im having second thoughts about.

#### junixophobia

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[citation][nom]shineon2010[/nom]Very good info , alot of products that im having second thoughts about.[/citation]

Just buy an automatic inverter that works for hours with a car battery

#### junixophobia

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[citation][nom]shineon2010[/nom]Very good info , alot of products that im having second thoughts about.[/citation]

Just buy an automatic inverter that works for hours with a car battery

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#### Guest

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Im missing the portable powerstation, especially the spps-200.
i wonder how that scores against the others.
i think they are from novuscell

#### junixophobia

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sorry guys, just gettin the hang of this...

#### Onus

##### Titan
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If you deep-cycle a car battery, you'll kill it in a matter of weeks, as its thin plates deteriorate. For deep-cycle applications, you want to get an AGM battery, containing much thicket plates; and even then you don't want to drop the SOC too much between charges, perhaps 60% is the lowest you should go.

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#### Guest

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Carrying an extra battery adds a lot of weight. And once the battery is depleted, you are dead in the water if the power socket is out of reach.

If I am going off grid, I would rather bring a solar panel and charge the battery I already have in my device.

#### acku

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Which sonar panels are you looking at? I use Brunton myself.

Cheers,
Andrew Ku
TomsHardware.com

#### agnius

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I am debating between Brunton, Powerfilm and Voltaic.

#### acku

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I have all three. What's holding up your decision?

#### agnius

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Andrew,

According to my calculations I would need about 25-30W to power/charge a netbook directly and charge my camera battery.

In theory Solaris 26 could do the job, but I am not sure - I have not read any reports about it. I was planning running Targus DC adapter from Solaris 26 straight into a netbook (I had HP Mini but it broke so now I am looking at Lenovo X120e as a replacement).

Also, I read that CIGS panels after being stored in the dark take days to reach their peak output. Solaris is CIGS, PowerFilm 30W is silicon which does not have that problem.

But PowerFilm 30W is also considerably larger which makes it less feasible to deploy while riding. Hence I am looking at Voltaic panels which are much smaller, but I am not sure how to route power without an intermediate battery from them (because they are 20V).

I am stuck in this decision loop while looking for more information.

#### acku

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Are you only trying to charge the camera and netbook at the same time? I assume the camera charger requires an AC outlet?

#### agnius

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Andrew, I am not trying to charger them both at the same time.

Canon LC-4E accepts also DC 12-24V, and it would take CB570 Car Battery Cable adapter.

It is the issue of advertised/actual power produced by the solar panels. By my calculations, the charger would draw about 24W. That was based on the information on the back of the charger stating Volt and Amp ranges required.

I am not sure about a solution for going from 20V to 12V on a Voltaic panel. Also, can Voltaic panels be daisychained for higher Amperage?

#### acku

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You're going to need some sort of power regulator to compensate for the fluctuating voltages, and never assume that you're going to get the advertised watts unless you have optimum sun all day long.

I'll ask Voltaic, but I believe they can. You're going to have to get the right cable, of course.

#### agnius

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I figured that Canon LC-4E has a power regulator built in as it accepts a wide range of voltages.

As for charging a netbook - I would use Targus 90W AC/DC Laptop Charger that also has input range of 12-30V. I wonder if there is the minimal current for Targus adapter to start working?

#### acku

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The Targus 90W is my favorite of the third party chargers.

Most devices have a power regulator that accepts different voltages. The problem is that if that component fries, the devices is dead. I prefer to have an external battery as an intermediate because it stores any charge that isn't passed directly to the device. You lose maybe another 2-4% in electrical efficiency with an intermediate battery, but you gain complete safety. If you're in the field, that's invaluable.

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