Introduction: NEW BATTERY FOR OLD POWER BANK

Hi friends.. this is my first instructables, sorry for my english. I am from Indonesia and love to see many DIY from instructables for years. I have more time recently to start looking around and doing some.
I like about recycling and reuse, so I started looking around and there is three old power bank APC lying down in my drawer. I love many UPS from APC but for these power bank I was quite dissapointed, but I still buy another until I have three piece of it and said, it is really a bad product.
So I have time to find which one is bad, the motherboard or the battery. it is the time to find out.
I still love the my APC power bank, I plan to change the battery and reuse again for my smartphone.

Step 1: OPEN THE CASE

this product has a good casing design and quality. There is no screw so I try open it using cutter and screw driver.
After it is opened we can see that the motherboard has many component and I think it is a good one. I opened my three power bank and remove the battery from motherboad using solder. I forgot to take foto the motherboard and the battery an for better picture so I download from internet. in the casing there is no information about the current capacity so I looked at internet and found this site...http://www.pcworld.idg.com.au/review/apc_australia/upb10_mobile_power_pack/225060/
the capability is said only 10 watt hours. hmmmm.. that the reason why I complain.. because It was for charging O2 pda phone that need many power.
The battery is a SKME battery and looking at google I found this website
http://www.alibaba.com/product-detail/606168-Lithium-Polymer-SKME-LPCS676065-2800mAh_486989558.html
so I found information that it is has 2700 ma and have 3.7 volt.

Step 2: Checking the Condition of the Battery and the Circuit.

I check the physic of the battery and the motherboard. all the battery in bad condition because it is not in normal (I dont know to say in english - FAT- ) then using digital multimeter I tested the output of the motherboard. one motherboard onky give 2.6voltage and the other two have 4.08 volt.
So I think, there is only two motherboad that still in good condition.

Step 3: Put the New Battery.

I buy at local store a samsung baterry with 3.7 volt and similar capacity 2800 mA.
But I make mistake when connecting the battery positive cable to negative of the motherboard, I didnt realize until there a smoke from the circuit.
So now only left one good circuit in my hand. So I solder again the battery to this good circuit in the right port. The I making hole and the end of the casing so the cable will nicely came out the casing.
I live in little town, and it is hard to find baterry holder for only one battery. So I using transparent tape to hold them all. when I get the baterai casing, it will nicer to see.

Step 4: Testing the Battery

I charge the power bank and then the led sign is on, it mean the powerbank doing the work to charge the battery.
after charge for several hours, I test it to charge my asus fone 8, and It can bring 30% increase in batttery status in my smartphone.
now, I am happy again with my old APC power bank.
please comment and advice.. thank
Jefri