Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: How long will it preserve the charge without being used?
Document: This worked fine for my HTC EVO 4G. But when I used it to charge my HTC ONE, I got a message warning on phone that the Battery pack was insufficient for device.Any one else try this on HTC One?I would like to find a compatible battery pack for long trips, (even though the HTC One has incredible Battery life)But, I do not want to use one that could damage HTC ONE battery, because it is rather spendy to replace.
My UNU not only kept my cell charged all day (my only source of Internet and phone communication), but also charged my daughter's 3DS...all on one charge! As soon as we got power back (5:00 PM) I plugged it into the computer right away. I'll never be without this little gem again!
I got two of these, one for the car and one for my purse. They are great for re-charging my cell phone on the fly and for allowing me to use my tab if it's low on power (takes a LONG time to re-charge a tab). I do wish there were a way to charge things that don't have a USB cable (my children's tablets) without having to go to a much larger unit.
It is convenience for me to take when i go to travel. And it can charge my phone for long hours.
It's really useful thing. 5000mAh is quite enough to charge my iPhone 5 device 3 times. Compact size and low weight is also it's advantages. I think my mobile will never be uncharged any more. Hope it will work for long time.
This works great! It holds the charge for a long period of time and I am able to charge my phone multiple times before having to recharge the unit itself. I can think of so many usefull situations for this device. I highly recommend it. It is lightweight and compact enough that I even take it backpacking with me.
If you are traveling long distance via plane; bus; or train, I recommend this. It has been on every trip with me since MIA, March 2013. I am in Chicago, and if I know I have a planned all day outing, I charge it the night before and the next day, I am off.Get it, you want regret it. Darryll, Irving Park
Instructions were unclear and had to read customer reviews to figure out the LED system. Says here red 0-33 , Green 33-66 , blue 66-100, and red flashing 75-100%?. What is this...took the whole night to charge my phone and now its been 8 hrs and I am charging my enerpak 5000mah and the LED is still blinking blue can anyone tell me how long it takes to charge this battery pak?
Awesome device.As we have a lot of power cut in Libya I found that this device is so helpful for me.I used it to charge my cell phone and my fi
I have used this to charge my iPhone and found it will provide about two charges before it is depleted . It does take a while to recharge fully when fully depleted ( 6-8 hours) .
Answer: Good morning-I use mine for school for charge it on a weekly basis (every Sunday) but I haven't noticed a huge decrease in charge over a week even if I don't use it during the week (10-15%).Hope this helps.