I will try to answer some of the questions and provide some additional information for the product.
CELL PROTECTION
You can use both protected and unprotected cells in thuis product, but avoid using batteries with a different charge percentage! I recommend using only batteries of the same brand in the same condition to avoid one cell charging another, this could possibly lead to cells becoming hot and fire/explosion. The charging process stops at max. 4.22V, which is exactly where it should stop. I have not tried if there is a low-charge-protection, but I think so. There is no overheat protection, so stay close to the cells and monitor the temperature every now and then, especially when charging in this setup for the first time. If it gets warm, better unplug the charger and let them cool down before you continue.
LOADING CURRENTS
I measured both charging currents. The chip responsible for charging the products internal batteries supports up to 1A loading current, which with 4 average cells (2200mAh) takes ~9hrs to fully charge them.
It does not matter, which input you use for charging, they are internally connected. If you find a power suplly with the round plug just make sure it is rated at 5V DC with a minimum of ~700mA or better 1A.
The output current is specified to be 1A too, but I measured currents up to 1,75A, but it probably wouldn't charge for a long time at this rate. So I think 1A is realistic.
PHONE COMPATIBILTY
This device does not short the USB data pins, which would help charging some phones. So if your phone is not charged (or charged painfully slow) you can try the following:
Open the case, bend up the circuit board. Below the USB out connector you will see the 4 pins in a row. Connect the second and third of them either by bending them to each other or by soldering. Do this at your own risk, it could break your battery pack and/or phone!
STATUS LED/FLASHLIGHT
the 3 LED indicate battery state. The green LED just glows very dimly, that's normal. While 3 LED indicate a rather fully charged battery pack, less LED mean less energy left. The indicator is more accurate, when there is no device connected and the switch turned off, because the 'flashlight' and phone charging drain some of the power.
I hope my information is useful for you; I just want to thank SunTek customer support for their great service with delivery problems and hope they appreciate my info given here.
Disclaimer: All information published here apply for my 2 boxes, and were found out by myself using a digital multimeter and data sheets of the manufacturers. I can not guarantee that there are no faults in there.