From day one when I got ZeroLemon 9300 mAh battery, the question of external charger for this battery was on my mind. You get a monster capacity, but it will also take at least 3x as long to charge it up and you can only do that inside of your phone. It's OK if you run out of lemon juice and put your Note 2 on a charger overnight, but otherwise you better have a spare fully charged battery. Plus, for some of us the use of ZL battery will be not daily thing. Bottom line, external charger is a must have. I have talked to ZL support and they confirmed about looking into rapid external charger, but no details about it available yet. So I figured to try something out myself.
The challenge is that ZL battery looks like a stock footprint on top of a large plate. Most of the regular single battery charges have small footprint where they could mate with battery contacts but ZL will be top-heavy pulling out of the charger. I came across this cradle charger from Tmart.com, it's about $15 and as a bonus you can charge the battery and sync your phone. Got it from here: Twin USB Cradle with 2nd Battery Slot for Samsung Galaxy Note II N7100 - Tmart.com
- they actually have it in their US warehouse so it arrived very fast. As a cradle it's OK, although just like any vertical cradle-stand it can accept only a slim case or Note 2 without a case. Also, for some reason with an included ac-adapter you can't charge at more than 500 mA (it was forcing it into USB charging mode). But that wasn't my main purpose.
In order to fit ZeroLemon, I had to modify this case where the back support of the cradle/stand had to be leveled off. Since I use dremel for my mods, I actually included a picture below for those who are interested. Using a cutting wheel to slice it off, and griding wheel to smooth out the rough edges. Turned out to be very functional! Because of the wide base of the charger/cradle, there is no wobbling or worrying the battery will pop out of the charger. The only drawback is that charging led light is covered by the battery, but if you look sideways you can actually see it: red - charging, blue - all done (I assume triggered by a target voltage when battery is fully charged). I took my depleted ZL (it was down to 3%) and set it on the charger overnight from midnight until 7:30am. I did use an included AC wall charger since I figured it said 1500 mA so it should charge it fast. In the morning popped the battery into the phone and to my surprise found it to be only at 32%. That would mean that wall charger was actually providing about 415 mA instead of 1500 mA. No surprise since you can never trust these labels. It could have been a typical 500 mA charger with some efficiency loss down to 415 mA of actual current. I decided to use my other "trusted" 2A wall charger. Kept it charging in the same setup from 10am till 1:50pm, popped it into the phone and battery went from 32% to 97% in under 4 hours!!! Which is approximately 1550 mA of supply from a wall charger, with some efficiency loss from original value. So if I would have used this wall charger from 3%, most likely I would have gotten to a full 100% charge in under 7 hours, maybe even 6 1/2 hours.
Pretty much charging circuit of that cradle/charge is able to handle high current input and can charge Zerolemon at relatively fast rate of 1500 mA supply. Plus, even after slicing a layer of back support of that cradle, I was still able to plug in the phone and charge/sync it (although through that micro-usb connector it was charging at USB rate, not AC).
Bottom line, it worked! Oh, and as a disclaimer I have to mention that I'm not responsible for any damage to your battery or your fingers if you decide to duplicate it
Here are the pictures: