I was provided a copy for review by Zanflare (GearBest PRC stock).


Official Product Specifications
- 4 different charge current options to choose from ( 300mA / 500mA / 700mA / 1000mA )
- It can charge simultaneously rechargeable batteries of different specifications ( 18650, 26650, 26500, 22650, 18490, 17670, 17500, 17355, 16340, 14500, 10440, A, AA, AAA, SC sizes )
- Provided with integrated LCD display to monitor battery parameters including voltage ( V ), current ( mA ), time ( h ), capacity ( mAh ), internal resistance ( mR )
- Overcharge and overdischarge protection
- Short circuit protection
- Overheat protection
- 0V voltage activation function
- Smart identification of damaged batteries
- Battery reverse polarity protection
- The 4 slots work independently
- CHARGE, FAST TEST and NORMAL TEST, three modes to select from
Specifications:
- Input: AC 100 - 240V, 50 / 60Hz, 0.6A max, DC 12V, 1.5A
- Output: USB 5V 2A
- Charge current: rechargeable Li-ion batteries 4.2V, 300mA / 500mA / 700mA / 1000mA, rechargeable Ni-MH batteries 1.48V, 300mA / 500mA / 700mA / 1000mA
- Discharge current: 300mA, 500mA
- Material: ABS
- Environmental conditions of use: humidity: 5 percent -90 percent; temperature: 0 Deg.C - 40 Deg.C
Product weight: 0.2700 kg
Package weight: 0.5700 kg
Product size (L x W x H): 18.00 x 10.00 x 4.00 cm / 7.09 x 3.94 x 1.57 inches
Package size (L x W x H): 20.00 x 18.00 x 5.00 cm / 7.87 x 7.09 x 1.97 inches
Packaging and Contents
1 x Battery Charger
1 x Power Adapter
1 x Car Charger
1 x Manual




Fit and Finish
The C4 is made out of ABS plastic and has a mild "texture" which gives the appearance of a subtle sheen as well as helping to reduce the visibility of finger prints.
All 4 slots are evenly spaced, which helps make it easier to insert/remove batteries from the center slots.





User Interface and Modes
Each slot can operate completely independently (for example, slot 1 can be set to charge, slot 2 can be set to Fast Test and slot 3 can be set to Normal Test). In order to set different modes for each slot, you have to insert each battery one-at-a-time, set the mode and then wait a few seconds before inserting the next battery. Each slot can also have separate a current setting. The mode and current is set within 10 seconds of a battery being inserted.
Operation:
* When battery is inserted, press CURRENT within 10 seconds to rotate through the current options (300/500/700/1000mA for Charge and 300/500mA for Test). 500mA is default.

Battery Chemistries:
* NiMH and NiCd
* Lithium-ion (4.2V ICR, INR, IMR, etc.)
x Lithium Iron Phosphate (LiFePo) Not Supported
Battery Sizes:
* 18650, 26650, 26500, 22650, 18490, 17670, 17500, 17355, 16340, 14500, 10440, A, AA, AAA, SC sizes
* Protected 18650s Fit. The Protected Panasonic NCR18650GAs fit at about 70mm. I estimate that it can fit cells up to about 72mm in length. Someone with a proper caliper will need to measure this.
* Like most chargers, 26650s will fit but only 2 will fit at a time in non-adjacent bays (width constraint).








NiMH ends around 1.45V.


Size Comparison

Wish List / Recommendations
I would recommend the following changes to make this my ideal charger. Maybe Zanflare can create a "C4 Plus" model.
1) I feel like the existing design is "upside down". Change it so that the display is on top, the batteries "point up" and the power plug goes on the top (side with the display). Examples: Nitecore D4 and Xtar VC4.
3) Make the whole unit about 2-3cm wider so that 4x26650 fit and also so putting in 4 batteries is easier. Since this charger is already big, I don't think this would be a problem.
4) Make the individual slot buttons (1, 2, 3 & 4) illuminated with a color LED or put an LED above each slot. Make Green=Charged & Red=Charging/Analyzing. This would make it easier to tell if charging/analysis is complete because it can be hard to see the display from a distance.
5) Make it possible to change the display for all 4 slots at the same time with the MODE button once charging/analysis is started. This would be better than having to click the button for each slot if I want to change the display.
6) Make it possible to have the display rotate through all the information automatically (auto rotate = ON/OFF).
7) Make it possible to keep the display illuminated when main power is connected (always on = ON/OFF).
Summary and Conclusion
I like the charge and discharge current options (300/500/700/1000mA for Charge and 300/500mA for Test). I know that some people prefer chargers that can support more than 2A+ for charging or 1A for discharging. However, I prefer charging/discharging my cells at lower speeds for better longevity and less heat. I normally charge my 18650s at 500mA regardless of charger used. The 300mA charging option is also great for people charging smaller cells like 14500s.
The charger has good size and ventilation and does not need a built-in fan. When charging 4 cells at 500mA, the charger gets warm. When charging 4 cells at 1A, the charger gets very warm (but not overly hot). If someone wanted to add cooling for heavy use, you could set this until on top of a cheap laptop fan since there are a lot of vents on the bottom.