Last week I purchased two of the exact same model Aili black/white 4-cell capacity (batteries connect in parallel) Power Banks (logo has "i" in the name Aili a graphic of a battery). This is the one with a small single flash-light (LED) bulb in the center of the top side, and on each side of the LED it has 2 normal USB outputs and the micro-USB charging input. On the right side facing the logo is a slide switch with settings for .5A, 1A or 2A output. The unit came without batteries so I randomly purchased several online, including a set of red Ultrafires (4000ma) and blue Ultrafires (5000ma). Along with one set of batteries came a 2-cell charger labeled "Video/Digital Camera TRAVEL CHARGER", Product name: Charger, Input AC 100V-240V ... Output DC 4.2V 650mA.
Now I tried to understand what kind of batteries to use here. Both sets of Ultrafires I purchased on eBay had no advertisement regarding them being protected or not but upon arrival and inspection they both turned out to have the button on the bottom and "hot" wire clearly going from the top of the 18650 down to the button. I then researched at every place selling this Power Bank online for more specifications but the info was very sparse. One site said "use unprotected batteries - protection is in power bank". I finally got an answer back from my Chinese vendor and he said "use unprotected" with no further explanation. I saw another vendor selling the same supply who warned that using protected batteries would damage the unit because it would confuse the protection circuitry.
So onward I went with testing the unit. In my opinion, when batteries are wired across a parallel strip, I would assume that should one "go down" - they all could potentially suffer and at a dangerous level, for example if one of them ever shorted it would take the rest of the bunch down with whatever damage the one getting shorted displayed, times a power of 4. A little scary ..... So I decided to forgo the warnings and since I didn't pay that much for the power bank, plus the length of the Ultrafire protected style battery was not too long to fit into this bank, I began charging the batteries which has arrived and continued with a stableized voltage of 3.91V. During the charge cycle, I continued to monitor the voltage levels and the temperature of the batteries as I charged the bank with a 5V 2A wall charger. I did not measure the amp output of the wall charger but knew it was close to 2A because it had no problem fully charging an iPad. I put a full charge on the blue Ultrafire 5000mA batteries while monitoring voltage and temperature. The temp never rose much above room temp but the voltage only climbed up to 4.07V before it topped out. I waited 24 hours with the device still charging and the charge still would not increase past 4.07V. Just in case I had a problem with this setup, I initialized my other Power Bank with another set of batteries and checked them to find after 24 hours, the voltage only rose to 4.09V. Curious if the batteries were bad, I plugged them in the no-name 2 cell AC wall-charger (I have 2 of these 2-cell charges, charged them a couple of more hours and the DMV reading went up to 4.21V - a "happy voltage" I was hoping from from the Power Bank charge but never saw.
Now my question here would be, does anyone think that if I rip the regulator button off the end of 4 of the Ultrafires, that the Aili charger might be able to zip them up 4.20V charge I am looking for, resultant of there being no protector in the circuit? I am not that nervous about the Aili being void of its own protection circuit since everyone selling it has said it does, but my concern would be having 4 unprotected cells in parallel and what happens should one of them decide to go down the road of no return and my exposure to the rest following suit. Another reason I am asking this before conducting the test is I had to trash 4 cells if the top charge from this device is still going to hover around 4.07V.
I have run through now 2 complete cycles of charging and discharging the Aili and the results and voltages are near exactly the same. From a 4.09V pseudo full-charge, I was able to power a setup of a small router and air-card that draws 1A for a period of 8 hours before the Aili shut itself off due to low battery voltage. The voltage level of the cells was observed at 3.21V when this happened.
I have currently removed the batteries from the Aili, and charged them up to 4.21V in the external wall chargers I have. I am now running a test to see how long the 1A load will continue to be powered when the starting voltage was at 4.21V instead of the Aili full charge value of 4.09V.
Now I tried to understand what kind of batteries to use here. Both sets of Ultrafires I purchased on eBay had no advertisement regarding them being protected or not but upon arrival and inspection they both turned out to have the button on the bottom and "hot" wire clearly going from the top of the 18650 down to the button. I then researched at every place selling this Power Bank online for more specifications but the info was very sparse. One site said "use unprotected batteries - protection is in power bank". I finally got an answer back from my Chinese vendor and he said "use unprotected" with no further explanation. I saw another vendor selling the same supply who warned that using protected batteries would damage the unit because it would confuse the protection circuitry.
So onward I went with testing the unit. In my opinion, when batteries are wired across a parallel strip, I would assume that should one "go down" - they all could potentially suffer and at a dangerous level, for example if one of them ever shorted it would take the rest of the bunch down with whatever damage the one getting shorted displayed, times a power of 4. A little scary ..... So I decided to forgo the warnings and since I didn't pay that much for the power bank, plus the length of the Ultrafire protected style battery was not too long to fit into this bank, I began charging the batteries which has arrived and continued with a stableized voltage of 3.91V. During the charge cycle, I continued to monitor the voltage levels and the temperature of the batteries as I charged the bank with a 5V 2A wall charger. I did not measure the amp output of the wall charger but knew it was close to 2A because it had no problem fully charging an iPad. I put a full charge on the blue Ultrafire 5000mA batteries while monitoring voltage and temperature. The temp never rose much above room temp but the voltage only climbed up to 4.07V before it topped out. I waited 24 hours with the device still charging and the charge still would not increase past 4.07V. Just in case I had a problem with this setup, I initialized my other Power Bank with another set of batteries and checked them to find after 24 hours, the voltage only rose to 4.09V. Curious if the batteries were bad, I plugged them in the no-name 2 cell AC wall-charger (I have 2 of these 2-cell charges, charged them a couple of more hours and the DMV reading went up to 4.21V - a "happy voltage" I was hoping from from the Power Bank charge but never saw.
Now my question here would be, does anyone think that if I rip the regulator button off the end of 4 of the Ultrafires, that the Aili charger might be able to zip them up 4.20V charge I am looking for, resultant of there being no protector in the circuit? I am not that nervous about the Aili being void of its own protection circuit since everyone selling it has said it does, but my concern would be having 4 unprotected cells in parallel and what happens should one of them decide to go down the road of no return and my exposure to the rest following suit. Another reason I am asking this before conducting the test is I had to trash 4 cells if the top charge from this device is still going to hover around 4.07V.
I have run through now 2 complete cycles of charging and discharging the Aili and the results and voltages are near exactly the same. From a 4.09V pseudo full-charge, I was able to power a setup of a small router and air-card that draws 1A for a period of 8 hours before the Aili shut itself off due to low battery voltage. The voltage level of the cells was observed at 3.21V when this happened.
I have currently removed the batteries from the Aili, and charged them up to 4.21V in the external wall chargers I have. I am now running a test to see how long the 1A load will continue to be powered when the starting voltage was at 4.21V instead of the Aili full charge value of 4.09V.
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