Portable Charging From A Battery

Music

Senior Member
Feb 5, 2011
571
7
I've used my "Power Pack" a few times since I got it, and it has worked well. I was able to recharge the tablet's battery once a day, and recharged the Power Pack at night. You just need to remember to use a slow charger, as the charger you get with the Nexus 7 will only partially charge the Power Pack (the power pack's charge light goes out after a short time.) You also should be very carefull when recharging the tablet in situ as the plug sticks out from the end and you could possibly damage the USB port or the charging cable. I'm looking into getting a right-angle micro-USB charge cable extension.
 
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Music

Senior Member
Feb 5, 2011
571
7
After some experience wit the "Power Pack" I referred to in #15, I would NOT recommend you buy it. No matter which charger I used, the charge LED would only be lit for a couple minutes, then go out, indicating the thing was fully charged- even on the first charge! There is no way to check the charge level (it's not a 'smart' battery) and so you can't tell if it will work.

I think you're better off getting a Power pack at a commercial vendor that has quality stuff, like Amazon or Radio Shack/BestBuy.
 
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Music

Senior Member
Feb 5, 2011
571
7
I got the Ravpower 10,400 mAh battery, and I'm satisfied with it. It has two output ports, rated 1A and 2A with a 3A total output (obviously.) Some YouTube video reviewers stated that the battery didn't really have the 10,00ma capacity, but they didn't realize that no battery can actually store the stated capacity nor transfer it completely to another battery (due to internal resistance, parasitic power losses, etc.) and one guy even went so far as to tell viewers NOT to use the "2-A" port because you could burn up your phone battery! Huh?? I think he needs a course in basic electrics. Suffice it say that it should have a good power capacity in the small package (about the size of a deck of cards.)
 

Note Edge Guy

Junior Member
Jul 17, 2015
1
0
hj guys

i have built a perfect phone charger....
I read and tried every thinv and every way to build usb phone charger that charge my phone fast and can be recharge ....i tried the lm7805 voltage regulater in every way but with no avail. ..i mean it's not perfect....
so i start to build phone charger by another way...
I've an old laptop battery. ..i toakeit and opened it. ..i found 6 li-ion batteries with 11 volts ...these are chargable ....also i bought a phone car charger with 2500 mA...i opened its case and i toake the board and i connected it with 11v li-ion batteries and test it....it was very fast charging and the voltage of the batteries was get down very slowly so this is perfect. ...then i get a female laptop charging connector and connect it with the batteries with led and a diod and start charge the batteries with laptop charger wich gives 18v....it's take 2 hours to full the batteries. ...and in the end i used the batteries case and finish it....it is really perfect. ..
the case is square. ..acer laptop battery
 

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Music

Senior Member
Feb 5, 2011
571
7
You must remember a few things when you charge your tablet or phone from another battery: First, the capacity of the phone battery on the label is wrong. The phone battery has some internal resistance, so you will have some power loss when charging, and you will really need to charge to over 100% of the phone battery's rating to show a FULL charge. Second, the supply battery will never deliver 100% of the capacity, because it will lose some in heat and resistance also. The adapter/charger and cable will also cause a little power loss.

The purpose of using a spare battery to charge a phone or tablet is so you can keep using it for a little while until you can get to a high-power charger, like in a car or house.
 

Music

Senior Member
Feb 5, 2011
571
7
OK...
I would suggest to everyone that unless you are an avid electronics hobbyist, making a spare battery for remote charging isn't a good idea, because the battery packs that are available commercially have a MUCH larger capacity (being made of LI-ion cells) and having some fancy electronics, more than one charging port, status LEDs, etc.
 
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