Related
They have the same connection dont they? What about current, amperage and all that good stuff?
We can deduce from the fact that they both can charge on your pc USB slot that their individual chargers are of same polarity and COULD be interchangeable. A quick check on my collection of chargers that charge also on USB is: K-Jam 5v 1.0 amp max, Atom 5v 1.0amp max, Jabra 800 6v 205mAmp 8) Check with your razr charger and interchange the chargers at your own risk :lol:
Victor
NO NO NO NO NO NO NO NO NO
Don't do it, I had somebody who had been charging there Compact with a razr car charger and now it won't charge at all. There appears to be some difference somewhere. Don't even risk it.
It wasn't the fact that the car charger was for a RAZR, the problem was, it was probably a generic charger. I fried a brand new iPAQ with a car charger I bought on eBay. I learned my lesson...
The *OFFICIAL* Motorola RAZR charger is rated less than the Wizard. Both the RAZR and the Wizard can charge via the USB. Both have the same pin outs. If the RAZR charger were rated higher than the Wizard, you should be concerned.
I've been using a RAZR charger since I got my K-Jam in (when was the very first shipment?) and it charges fine every time.
The ratings on my Motorola V3 charger:
Input: 100v-240v ~ 50/60Hz 0.2A
Output: 5.0V - 550mA
If someone can explain how why the RAZR charger is bad on the Wizard, I'd love to know why.
In fact, Nokia sells two different chargers. On some phones, they come with a standard charger. But you can buy a "fast" charger for the phone and the only difference is a higher AMP rating. I used to work for Cingular and have seen personally the same phone ship with both chargers...
-Mc
for grins: http://en.wikipedia.org/wiki/Universal_Serial_Bus
Power supply
The USB connector provides a single nominally 5 volt wire from which connected USB devices may power themselves. In practice, delivered voltage can drop well below 5 V, to only slightly above 4 V. The compliance spec requires no more than 5.25 V anywhere and no less than 4.375 V at the worst case; a low-power function after a bus-powered hub. In typical situations the voltage is close to 5 V.
A given segment of the bus is specified to deliver up to 500 mA. This is often enough to power several devices, although this budget must be shared among all devices downstream of an unpowered hub. A bus-powered device may use as much of that power as allowed by the port it is plugged into.
Bus-powered hubs can continue to distribute the bus provided power to connected devices but the USB specification only allows for a single level of bus-powered devices from a bus-powered hub. This disallows connection of a bus-powered hub to another bus-powered hub. Many hubs include external power supplies which will power devices connected through them without taking power from the bus. Devices that need more than 500 mA must provide their own power.
Click to expand...
Click to collapse
The max that the USB port can put out is 500mA. The V3 charger is between the USB port and the official HTC charger.
USB: 500mA
RAZR Charger: 550mA
HTC: 1A
Don't buy a generic charger. Buy a name brand charger...
Also, for more details about the USB pinouts than one man can digest in one sitting, read that entire Wikipedia article. I did... wish I hadn't.
-Mc
the same discussion is going on over at hofo or ppcdubai, forgot which one, but thers several posts with "I know someone that...." or "my friend did..." and devices ended up being fried. well i'm telling you from first hand experience. about a year ago I bought a belkin razr car charger from walmart and i've been using it on my jam and now my k-jam and my battery and device aren't damaged. I don't know the rating on it but I suggest u check the rating of anything before u plug your device into it.
also that car charger didn't charge my sp3i, just to let ya'll know.
That discussion at HOFO was a question that *I* originally asked back in December. I just posted the same information over there about 5 mins ago.
Buying chargers for 4.99 on eBay will kill your device every time. I learned the hard way. If you buy a name brand product, your fine.
Specs says it's OK. Experience with a name brand charger (your belkin and my Motorola) says it's OK.
But like I said above, if someone can point out a hole in my logic, please tell me. I've been wrong before but I don't think I am on this one.
-Mc
Works for me...
Motorola branded AC charger, rated for 550mA current
Generic car charger for mini-USB, made in China eBay, no specs.
Both work fine with my Razr V3 and my Qtek 9100. Bit of a risk to use the car charger, but it's worked well with the Razr. Agree completely with McHale, your logic works fine. If your AC converter and DC power source are up to USB spec, you should in theory be able to charge both devices.
The unknowns are the custom circuitry the cheap converters use to "prevent" overcharging. Some have simple diode rectifiers, some have weak op amp current sinks, etc. Basically, some of these overcharge circuits don't work at all and you get a fried device. You get what you pay for, usually.
Hi
I have 2 phones - an O2 XDA Mini S (a K-Jam) and a Motorola Razr V3. I use the Motorola chargers, both wall charger and car charger, every day for both phones and have done so, without problems for months.
Shaun
nope, doesn't work. Simple as that.
I have both, I tried - used one at the office, the other (razr) bedside. The charge light comes on, then goes out in five seconds.
Every once in a while, it actually would charge... finally gave up and got rid of the razr charger.
Hi
It definitely works for me - I have actually never used the O2 charger; I use the Motorola wall charger at the weekends and the Motorola Blue Car charger every morning.
That is the only way I charge my O2 XDA Mini S - so it obviously works in my case!!
Regards
Shaun
I have been using my Razr charger (car and home) since I got my KJam a few months ago. I had a surge and my official charger was fried in a surge.
The only problem I have had was when I completely drained my battery (GPS software that prevented power down) I was not able to bring my KJam back to life with the RAZR or USB charger.
I connected my KJam to a friends official charger for a couple of minutes and it was fine.
I bought a new charger from Expansys, but I still use my RAZR chargers as well.
I don't understand the reasoning, but you can not charge the phone via the USB unless it is on. Since the RAZR charger is basically the exact same specs as a USB port, same rule applies.
If the battery is dead, there's no way to turn it on for it to work.
At least that's my uneducated guess.
But like I said, I've been using the RAZR charger since the end of December and have never had a single discharge or any other problems.
-Mc
I have found a 3000 mAh battery on eBay for around $100 with shipping, and since I'm pretty tired of the short battery life I'm considering it. I was so embarassed when the family went skiing yesterday! My kids have smartphones (Qtek 8030 & 9100 - I keep the family on intelligent phones, my wife has a Qtek 8500 Star Trek) and they had MP3's playing all day in the slopes with only one of the three battery level stripes dissappearing, while I had to put my Atom in the car and charge it after only three hours, when it was down to less than 15 %! Which is why I'm considering either an expensive 3000 mAh or one of those cheap USB chargers where you just put in a regular AA (or was it AAA?) battery and hook it up to the mini USB port. So has anybody tried either of them?
The battery-based chargers work, there are AA and AAA models 'round here (>1 battery each) - but I haven't tried it on the Atom yet. Be aware that the Atom has a charger protection mechanism that refuses to let the battery trickle charge if it doesn't provide a rated amount of juice (this is not mentioned in the O2 site, but it's there. It's the reason why chargers that normally work on the Mini won't work on the Atom).
Personally, I'd rather get a charger that works practically everywhere than to grab an extended battery.
(Have you considered those new fangled solar powered chargers? Some of them contain internal batteries that store energy, even under artificial light - and it is this battery that is used to charge your device. This could be a better idea, but be sure to check if it works on your device.)
PS: a PDA eats battery like no tomorrow because it usually uses better processors and interfaces - the XScale on ours is the eater here. Smartphones run on a lower rated processor/card slots, and don't have touch sense screens, and thus can last for much longer. If you really need your PDA to last, well, forever - you might want to consider an extended battery or one of the CPU scaler programs.
Thanks! I forgot to say that I ate the battery with the CPU at 208 mHz (with XCpuScalar)... Anyway, I have two of those AA-chargers on the way, I'm glad they work! At home I have GP PowerBank chargers and a bunch of rechargable batteries which I will use for this. With any luck a few of those will last me all day on skis!
And I didn't know about that protection mechanism in the Atom, I have been wondering why it's so extremely picky when it comes to charging from USB cables and stuff like that.
And I hadn'd even heard about the solar charging option, but I see there are a bunch of those on eBay. They look pretty cool, but unfortunately when I'm in the sun I seldom stand still long enough to put the charger and the phone anywhere for charging. If there was an affordable vest or jacket for that, though...
I think the O2's charger protection mechanisms were discussed here:
http://forum.xda-developers.com/showthread.php?t=276400
Methinks Quanta borrowed something from Motorola.
The solar charger, btw, works under incandescent light as well (I have one - useful in a hotel room where you don't have a plug but you have access to a desktop lamp). More expensive models can supposedly work under flourescent light, but I'm a cheapskate. They work by having an internal LiON themselves, which is trickle charged by solar/incandescent power - and then the battery itself is the one that charges your PDA's battery. Many different types exist, but most of them have a 1000-3000mah internal reservoir, and the better ones have different voltage settings for differenet devices.
Yeah, but the problem is that they're too big for my jacket pockets, so they won't help me skiing.
Well, that didn't really work. So I have decided to go for quantity instead of quality: Ordering three batteries, one with a charger that charges it ouside of the phone as well as charges the phone. All in all around 40 dollars, which gives me four batteries to play with. I ain't gonna use up my phone next time I'm in the slopes! And I think the same batteries can be used on my next phone, the Atom Life. It's got a larger capacity battery, but it looks like it's the same physical shape. Then again I may be wrong, but at least I will have no problems on those boat trips this summer!
And that worked! Not to mention that the original battery has to be total an utter crap! On these new batteries I had more than twice the battery time I had on the original. Of course it's been used for about two years, but still it shouldn't be that bad! I have five year old PPCs that hasn't changed that much in battery time. Anyway, with three new batteries and the old one I can keep going for a looong time!
Mastiff said:
And that worked! Not to mention that the original battery has to be total an utter crap! On these new batteries I had more than twice the battery time I had on the original. Of course it's been used for about two years, but still it shouldn't be that bad! I have five year old PPCs that hasn't changed that much in battery time. Anyway, with three new batteries and the old one I can keep going for a looong time!
Click to expand...
Click to collapse
bro did u tryed u,r AAA batery charger for Aom Life? i also bought a AAA battery charger fro my first Atom but not working after that tryed for my Atom Exec saem now going to check on my Atom Life,, thought to ask u befor check it.......
Some types works, some don't. It seems like only the black type work,while the shiny metallic one doesn't.
Just thought I'd pass this along. This little battery charger for the Wing or Dash charges your phones battery with just one AA battery. It kicks up the voltage from 1.2-1.5v to 5.7v. Saps the hell out of the AA battery but charges the phone -- its really cool. I bought two of them.
I'm Not the seller - I have No interest in selling these. Just thought Wing users would like to know there's such a thing out there.
http://cgi.ebay.com/EMERGENCY-AA-BA...ryZ48492QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
How long of battery power do you get for 1 AA battery?
If it has small USB connector, can I use it for TyTn II (Kaiser)?
I will time it
Hi -- I've not timed it yet but I will and post results.
Iffy
I got one of those little portable chargers for mobile devices. It's a neat concept. Upon pruchasing one of those (in the US) for $19.99, it came with a cheap AA battery, and several adapters for different mobile phones. I used the AA battery that came with it and it charged my HTC Herald P4350 for 20 minutes. You can actually drain (and cause damage too) your phone battery it you have it plugged in (with a dead AA battery) your device (it said so on the package). This is my experience and others may be different. In a nutshell, the amount of time it charges depends on what kind of AA battery you use. Again, this is my experience.
True
Yes it does depend on the type of AA battery you use. A Lithium AA will give you much more than a rechargable NMHI. I put in an alkaline AA and talked with my brother for two hours today using my Bluetooth headset and this thing kept my phone to 100% charge the whole time.
I am not planning on keeping it plugged in all the time especially when its dead.
I am going to use NIMH AA batteries in my Solar Charger that sits on my Dashboard. Rotate them out and get basically free energy. Hey I know its not going stop the Icebergs from melting but its something.
Here are the specs from the package:
Input 1.2-1.5v
Output 5.7v
Standby 80 hours
Talk Time 2 hours
Charge current 850-2300m
Discharge 150-530m
*This one says nothing about draining your phone's battery in fact it says if using NiCads or NMHI to make sure it drains all the way down before you disconnect it. It says best results can be obtained using a Lithium AA but who can afford that.
It Should work with the Kaiser
gogol said:
How long of battery power do you get for 1 AA battery?
If it has small USB connector, can I use it for TyTn II (Kaiser)?
Click to expand...
Click to collapse
Yes it has a mini USB connector and it should work with the Kaiser but you may want to ask the seller to be sure.
I have been pondering...
Our phone is awesome in every aspect.... battery life is between 6 hrs ~ 7 hrs depending usage...
However... charging the battery seems to take FOREVER !!!!!!!!
it takes like 5+ hours to charge completely
if you want to charge it faster, wireless, phone, screen, etc needs to be off.
so that's the only inconvenient thing i found about our phone.
good thing is i can plug it in anywhere it has USB ports, including my car.
Make sure you use the correct charger. Many chargers that use the same socket do not charge at the same rate as the correct one due to internal wiring - I am not electrician but found this out the hard way.
Many USB/car chargers do not provide sufficient charge to even keep up with Athena power use.
AllGamer said:
I have been pondering...
Our phone is awesome in every aspect.... battery life is between 6 hrs ~ 7 hrs depending usage...
However... charging the battery seems to take FOREVER !!!!!!!!
it takes like 5+ hours to charge completely
if you want to charge it faster, wireless, phone, screen, etc needs to be off.
so that's the only inconvenient thing i found about our phone.
good thing is i can plug it in anywhere it has USB ports, including my car.
Click to expand...
Click to collapse
The SIZE matters... also in charging.
May be I am wrong, other in this forum are better than me in physic
but
1) The power usage when connected via activesync, having screen backlight 50%, Big HTC HOME is around 200/300 mA/h.
2) The battery is 2200 mA,
3)if you charge it with a 500 mA/h charger... 500-250=250 mA/h.... 9 ours to have a full 2200 mA charge,
Athena have also XSCALE CPU (clock increasing during heavvy usage) and the power usage could increase very quickly (I have seen some 1000 mA/h peak) due to heavvy memory and CPU usage, or microdrive access
Looking at DIVX movies, full screen, USB 1.0 connected... the power DECREASES (slowly)!
And I would like to add, that after several tests with different chargers, no doubt that using HTC chargers makes a big difference, specially the car charger.
In the case of car charger, using a normal one ( output 5V 500mA ) I made a trip of 300Km and the power level went down from 100% to 70% using TomTom.
And with the HTC charger ( 5V 2A ) leaving home with 50% and arriving the same destination with 100%, again using TomTom.
I'm assuming that using other GPS software the results will be equal.
I used car chargers with 500mA, 800mA and also 1A and I tought that the results should be different but in fact it seems to me that one thing is what the charger "says" and another thing is what can "give".
hope this helps.
poppey said:
.. it seems to me that one thing is what the charger "says" and another thing is what can "give".
hope this helps.
Click to expand...
Click to collapse
Yes, as I said it is a hard-wire issue
Yup, 2 pins need to be connected together before the Athena will go into "fast charge mode". You could hook up a 1000 amp bench power supply but still discharge your battery with GPS active - until you short the 2 pins. Don't remember which ones, its been discussed before on this board.
very insteresting...
yes i'm using the USB 500ma charger, just because past experiences has kind of though me that charging electronics with too much AMP it can burn it.
but it seems like the ATHENA can take that, since you have been using it.
I guess i'll shop around for a more powerful charger.
poppey said:
And I would like to add, that after several tests with different chargers, no doubt that using HTC chargers makes a big difference, specially the car charger.
In the case of car charger, using a normal one ( output 5V 500mA ) I made a trip of 300Km and the power level went down from 100% to 70% using TomTom.
And with the HTC charger ( 5V 2A ) leaving home with 50% and arriving the same destination with 100%, again using TomTom.
I'm assuming that using other GPS software the results will be equal.
I used car chargers with 500mA, 800mA and also 1A and I tought that the results should be different but in fact it seems to me that one thing is what the charger "says" and another thing is what can "give".
hope this helps.
Click to expand...
Click to collapse
AllGamer said:
charging electronics with too much AMP it can burn it.
Click to expand...
Click to collapse
Not true. Electronics is in many ways like the water system, with the water pressure equal to volts, and the gallons per minute equal to amps. However, there's one key difference - electronics will only use as much as its needs (and no more). Not like trying to get a drink from a high-pressure fire hose where you'll hurt yourself trying.
A 60 watt light bulb will only draw 60 watts and will not blow up even though it could draw many thousands of watts before the circuit breaker blew.
techntrek said:
Yup, 2 pins need to be connected together before the Athena will go into "fast charge mode". You could hook up a 1000 amp bench power supply but still discharge your battery with GPS active - until you short the 2 pins. Don't remember which ones, its been discussed before on this board.
Click to expand...
Click to collapse
This seems to do the trick with my Ameo.
http://www.expansys.com/d.aspx?i=154871
Hello,
i ve been searching for a way to extend the autonomy on the a501.
do you think i can use a cheap 12V lithium battery to charge it or take over when the internal battery is depleted ?
i m not very knowledgeable in electronics, i wouldnt want to damage the internal battery.
there seem to be very few commercial products that would fit this tablet and i m not really interested. i dont have 50$ for a +2h battery life --;
i was thinking of buying a 12V 5000mAh something battery from china and solder the appropriate DC connector on it, but im wondering if there are issues like, the Current needs to be stable at 1,5A or i might reduce the internal battery durability, things like that.
can anyone answer that ?
It's more complicated than that. The power supply probably has a circuit to regulate the flow of energy to the tablet, perhaps the tablet itself also has a circuit that works together, I don't know.
Short answer: buy a second power adapter
There are backup battery/chargers. Scosche goBAT for example.
Just Google around to find the best fit for you.
GullyFoyle said:
There are backup battery/chargers. Scosche goBAT for example.
Just Google around to find the best fit for you.
Click to expand...
Click to collapse
How would that work? Does the goBAT include a charging tip compatible with the A500?
Hello,
thanks for dropping by
its not helping really this is bs
power cat you say "probably" regulates the current. yes that is what i wrote that is what i hoped someone would clear up for me. i dont see how buying another wall charger is going to help me extend the tablet autonomy i would just as well carry the original one around.
gullyfoyle same sideways reading of the OP i would not pay 80$ for a marketed battery/charger.
i hope there are still people out there who can give an educated answer :/
this guy for example http://www.youtube.com/watch?v=LqxhEkDGkbg he says he learned it the hard way (bricked his phone?) because he put 4x(1.5V?) batteries to charge his iphone without the resistors (to get the voltage from 6V down to 5V?)
so there again, can there be issues with the discharge current rate or is it something about lithium batteries behaving differently from alkaline ones ?
i think i ll go ahead and try anyway. worst case scenario the battery will just sit there not putting out anything.
Why wouldn't you pay $80 for a backup battery charger. It was just an example. I'm sure you can find one cheaper after Black Friday, or even with a bit of Googlefu.
We aren't talking about normal chargers but portable charge devices.
http://www.scosche.com/consumer-tech/product/2073
For anyone in need of extra power, the goBAT II provides an innovative solution to the dreaded ‘low battery’ warning. The goBAT II is a powerful backup battery and dual port charger for your mobile devices. The internal 5000mAh ion battery will keep your devices going long after they normally would.
Advantages and Applications
A drained iPhone 4 can be charged 2.6 times with a fully charged goBAT II. An iPad can be charged up to 55% of full charge. This is the ideal battery for long commutes, airport travel and camping.
The goBAT II provides 2 USB charging ports that can be used at the same time. A 2.1 Amp port gives you the ability to charge mobile devices including tablets (iPad and Samsung Galaxy Tab). An additional 1.0 Amp port lets you charge your additional devices (iPhone, iPod, etc.).
Click to expand...
Click to collapse
Remember this is JUST AN EXAMPLE. The idea is to show these devices exist and are available for purchase.
http://www.engadget.com/2011/02/23/scosches-gobat-ii-portable-battery-pack-handles-two-usb-devices/
We'll just keep it real simple for you: the object you're looking at above is the Revive II charger, but slimmer, and with a rechargeable battery pack thrown in rather than a wall / cigarette adapter. Got it? Good. The goBAT II contains a 5000mAh rechargeable lithium ion battery, and it offers a pair of USB ports for charging. One's a 10-watt (2.1 Amp) port capable of handling high-maintenance devices like Apple's iPad, while the other is a more conventional 5-watt (1 Amp) socket. Scosche is also throwing in a USB adapter for the Galaxy Tab, theoretically letting those with divided households charge both an iOS and Android tablet at the same time. Brain melting, we know. It also works with the company's Revive charging app, which indicates how long a device will take to charge on any of Scosche's chargers and can also be configured to send an email notification once a device has been fully charged. She's all yours down at the source link for $89.99
Click to expand...
Click to collapse
See, others deem it "BRAIN MELTING".
And the cost of that type of thrill is reasonable, for the job it does.
But I can understand how someone would encourage another person to experiment with the guts of electronics they don't fully understand. Screw it up and you can always buy a new one.
Then again, you could buy three or four Gobats and save all the fuss and bother.
mr.bryce said:
Hello,
thanks for dropping by
its not helping really this is bs
power cat you say "probably" regulates the current. yes that is what i wrote that is what i hoped someone would clear up for me. i dont see how buying another wall charger is going to help me extend the tablet autonomy i would just as well carry the original one around.
gullyfoyle same sideways reading of the OP i would not pay 80$ for a marketed battery/charger.
i hope there are still people out there who can give an educated answer :/
this guy for example http://www.youtube.com/watch?v=LqxhEkDGkbg he says he learned it the hard way (bricked his phone?) because he put 4x(1.5V?) batteries to charge his iphone without the resistors (to get the voltage from 6V down to 5V?)
so there again, can there be issues with the discharge current rate or is it something about lithium batteries behaving differently from alkaline ones ?
i think i ll go ahead and try anyway. worst case scenario the battery will just sit there not putting out anything.
Click to expand...
Click to collapse
You will break your tablet.
The charger contains a complex integrated circuit. Sticking on a few resistors isn't gonna do ****.
Look at this for example, a simple wind generator has a complex charging circuit to regulare all the power:
http://www.instructables.com/id/How...nd-turbine/step8/Build-the-charge-controller/
Just google "how to make a charge controller" it's really not as simple as you think.
Quote from the site:
The general principal behind the controller is that it monitors the voltage of the battery(s) in your system and either sends power from the turbine into the batteries to recharge them, or dumps the power from the turbine into a secondary load if the batteries are fully charged (to prevent over-charging and destroying the batteries).
ok thanks ^^
now i understand that part
Short answer: buy a second power adapter
Click to expand...
Click to collapse
you are saying the overcharge controller (and other safety features) are all in the wall charger and are not integrated in the tablet.
so if i really really wanted to try i could plug any battery between 12 and 24V to this little guy couldnt i ?
http://www.ebay.ca/itm/220826123824#ht_3149wt_1163
As far as I know...as long as the voltage is correct (eg 12 volts) and the power adapter can produce the required amperage (1.5A) then the tablet will only take the current it can use.
So even if the power adapter is capable of producing 10A say, it doesn't mean it's forcing the 10A onto whatever is connected to it. If you use 1.5A (and if there was a way to connect multiple devices to it) you would still have 8.5A of current you could still take.
Oh the charge regulator would not be in the power adapter, that would be a very stupid design. It would be in the tablet it self to regulate how much charge it requires. I don't know of any power adapter that takes feedback from what it's charging to regulate the current.
It's the same with laptops, that's why you can buy universal laptop chargers when the one you have breaks, you just need to make sure it can supply enough amperage to power your device.
The power adapter is just a simple device that converts 110-240v 50/60hz voltage to 12v and upto whatever amperage it is designed for.
Power plugs in the house are designed at 110-240v to a maximum of 2400W (so ~20a for 110v and 10a for 240v) do you think whatever you plug into it uses up 2400W of electricity at once? No, it just takes what it is required (amperage), that's why you can plug a power strip with like 2-10 additional plugs without any problems unless if try to take more than 2400W in total.
Basic high school physics should of taught people this.
first sensible answer i get thank you daemos i m just not gonna take any chances considering the lithium technology and the fact they could use a "stupid design" for shorter gadget lifespan. if anyone has ever modded a car charger i d love to read about it.
mr.bryce said:
first sensible answer i get thank you daemos i m just not gonna take any chances considering the lithium technology and the fact they could use a "stupid design" for shorter gadget lifespan. if anyone has ever modded a car charger i d love to read about it.
Click to expand...
Click to collapse
Lithium ion batteries must be charged at a very specific voltage. So all charging regulation mechanisms would need to be inside the tablet.
I'm pretty sure the ones inside the tablet are definately below 12V so anyone thinking that the AC adapter has any fancy mechanisms to detect feedback, and regulate charge and control the voltage given to the Li-ion cells is incorrect.
Is it safe to use one of THESE to charge or run the tablet?
They also have a 6800mAh ver.
WOW YOU MEN Complicate everything
SIMPLE EASY .. Look at the output voltage of the the power brick for the iconia.. the part that you plug into the wall..
got something that OUTPUTS 12V AT 1.5 AMPS and you are done.. the Li Batteries as in all LI BATTERIES HAVE THERE OWN charging regulators in them.
The reason for this is because if a Battery is drained to a low state it will GET HOT AND OVERHEAT.. NI-CD Batteries can take and handle this heat.. Li batteries become a mini bomb at these temps.. So the are self regulating.. This can be proven by getting a cordless drill hold the shaft from running.. the drill will heat up the battery the device will STOP FUNCTIONING.. Remove the battery and put it back in . it will work again..
Now with that said.. most Li devices say make sure you have 20% or more battery life before flashing and so on.. This is because the DEVICE WILL NOT RUN On the power port. the port only connects to the battery. and in some cases the display lighting.. My cell is this way. if i run the battery until its dead or using gps on it. it will drain the battery faster then it can charge . causing it to not work until you charge it for 5 minutes or so.. this would assume that using a external battery to charge it .. the external batteries themselves would need to be more then 12 volts and atleast double the amps.. then regulated to the 12v 1.5 amps . think of this like pooring water thru a funnel.. to maintain the 12v 1.5 amps. You can test my theory by taking the battery out of your cell phone and trying to run it just on the power adaptor only.. I KNOW MINE WILL NOT RUN.. however if it has older battery technology it will..