ISDT C4 EVO Smart Battery Charger with Type-C QC3.0 Output for AA AAA Li-ion Battery with IPS Display Screen and Fire Preventionn Material (Black)

IMPORTANT: Please be aware that this review is for the newer C4 EVO model. Most of the reviews found here on Amazon are for the original C4 charger and even some of the reviews for the new C4 EVO have flat out erroneous information. Please read this review in it's entirety as it may clear up some errors I have seen reported by others in reviews here.Let's start with a description of the unique physical layout of the charger. The charger includes 4 vertically arranged bays and 2 horizontally arranged bays. The vertical bays are for use with AA and AAA batteries only. The horizonal bays are for use with Li-Ion and similar chemistries. I won't rehash all the sizes supported, these are clearly listed in the Amazon listing. A couple of notes related to this:Only the vertical or horizontal bays can be used at any given time, they cannot be used simultaneously. So this means that you can service only AA / AAA batteries OR Li-Ion cells, not both at the same time.A maximum of 4 AA batteries or 4 AAA batteries or any combination of up to 4 AA / AAA batteries can be charged at once. Note that this is different from the original C4 could only accommodate a maximum of 2 AAA batteries. The contacts for the AAA batteries in the original C4 were horrible (in my opinion). The C4 EVO has solid fixed point contacts, seperate contacts for the the AA and AAA batteries. Since there are no moving sliders as in many chargers, this should prove to be highly durable.The horizontal bays can accommodate up to 2 Li-Ion cells. There is one review that states that these can accommodate only unprotected 18650 cells. This is flat out wrong for the C4 EVO. It easily accommodates the 18650 protected cells as well as unprotected cells.The same review also incorrectly asserts that there is no analyze or cycle option available. This wrong but I think that there is a very good reason that the reviewer missed this. I admit that it took me a long time to stumble on this because it was not very intuitive. In the menus, you will see an option called "chemistry". By default this is set to "Auto" meaning that the charger will determine by itself if the battery in any given slot is Li-Ion, NiMH, etc. When set to Auto, the only options that you will see are "Charge" and "Destroy". To see the other options (discharge, storage, analyse, cycle, and activate) you need to manually select the chemistry. Once you have done this, all options will be available under "Task" in the menu.Versatile power options: The power input on the C4 EVO is a USB-C connection. Note that no charger is included with the unit - you will need to supply your own. The adapter that you supply will need to support either QuickCharge (QC) 2 or 3 protocols or the Power Delivery (PD) protocol. You can also use the USB port on a computer as a power source. A few important notes regarding this:This charger can charge batteries at a high charge rate (up to 3 amps per cell) / 36 watts maximum for all batteries. If your power adapter is not capable of delivering at least 36 watts at 5V or 9V then the maximum charge rate may be limited to a slower charge rate. If you use a USB port on a computer, make sure that you use a USB 3 port and NOT a USB 2 port. A USB 2 port can only deliver 500mA of current which is only half the 1A minimum needed by the charger. However, the fact that you can even use the USB port on a PC is a really handy feature when on the road with a laptop.Fan: The charger has a cooling fan so be aware that the charger will not run completely silently under all conditions however, I have found the fan to be FAR quieter than the original C4 and it has not bothered me in the least.Hard buttons: The original C4 had a touch sensitive area where there are now physical buttons. Personally, I find the new buttons to be a big improvement as the touch sensitive buttons were more prone to erroneous input.Options galore: Wow - there are a lot of options. You can charge, discharge, analyse, cycle, activate, and place your batteries in storage mode. I'm particularly in love with the storage option. If you are not familiar with this, let me explain: LiIon (and similar) chemistry batteries don't really tolerate long term storage fully charged. As a result, it is best to store these batteries at a lower voltage. As an example, I have a lot of LiIon batteries that I keep only for emergencies to power radios, flashlights, etc. If there are reports of storms or potential emergencies in the next few days I will charge the batteries fully so I'm fully prepared. Otherwise, I will discharge them to a voltage that is healthier for long term storage. This charger can automatically charge or discharge batteries to a level that is best suited for long term storage. Nice feature!Advanced options: For advanced users there are some very advanced options. For example, for LiIon batteries you can set the precise voltage at which charging should be terminated. For NiMH batteries, you can specify the delta V used to determine charge termination. I would strongly suggest not altering these unless you really know what you are doing and have good reason to do so, but the fact that these options are even available are pretty fantastic.USB-C: Just about all my portable electronics use USB-C these days. Having to keep other adapters and cables to support a charger using Micro USB was really annoying. With this charger I am finally free of that and now only need USB-C. This to me is just the icing on the cake of an exceptionally well executed product.Technical Support: I had one or two questions for Technical Support so I set an e-mail to them. I was surprised to get a friendly, through explanation to my query within less than one hour. Very impressive!

After looking around at many different chargers which included the BT-C3100 (3400), Litokala Lii-500S, and many others, I decided on this one because of the very controllable user interface, up to 3 Amp charging current, wide battery chemistry coverage, very adjustable charge and discharge currents in 0.1 Amp increments, excellent display, with plenty of information, plus the upgradeable firmware (software that makes it work).In choosing this charger, I was aware that I sacrificed the convenience of battery size and number of batteries that can be charged at one time, given the limitations of the charging bay. It allows for up to (4) AA, or (2) AAA, or (2) 18650 batteries and similar batteries to be charged simultaneously. You cannot, for example, charge a AA or AAA battery if you are charging a 18650 cell. This limitation can be overcome with adapters that use the 4 AA charging locations, wired to external battery holders. Some 3D printable designs for these adapters are available for free on line, and some of them are available for purchase; I have seen adapters for (4) 18650 or (4) AAA cells. I chose to design my own adapter, which allows me to use from 1 to 4 adapters individually, and use the remaining AA charge locations in the charger itself.Once you connect the power, the display will show the voltage of the power supply. You can adjust the charger settings from this screen. These include language, buzzer volume, display intensity, the use or not of charge interruption by cell capacity, time after battery insertion for auto charge to start, battery information display scroll time. I chose manual charge start, because it allows for the relaxed adjustment of the parameters under which the battery just inserted will be charged; this is very important if you are charging different chemistry or capacity cells, or if you want to perform different operations for each cell.When you insert a battery, the screen will show the voltage of the battery before it starts charging. It will also show the battery charge parameters for you to choose. The charger will then time to auto charge or wait for a manual start.The charger can automatically guess the chemistry and charge/discharge parameters, and operation to be performed. I recommend using manual selections. Once you select these parameters and the operation to be performed, you will be offered the same options for every cell you place in the charger.Once the operation starts, the display will show all relevant parameters and values for each cell, for the amount of time you chose on the charger setup screen, and then scroll to the next battery. You can manually switch the screen to show some of the parameters and a voltage vs time graph.I am very pleased with the charger, but:- It would be better if it had the conventional spring loaded charging bay contacts that allow to charge from AAA to 26700 cells.- It would be even better if you could charge 9 Volt batteries.- The use of stronger charge contacts would also be a welcome improvement.- Some have complained about the internal fan noise level

The initial unit I received came with a loose part inside, amazon exchaged it. The new unit works good, the features are very handy and include all the scenearios you may want. The charger is small, lightweight and with a beautiful display. has and automatic mode which works ok regulating the charging current as per battery's internal resistance and a manual mode which I prefer for manually settings current, voltage and full charge condition.New firmware updates delete the power compsumtion display, so I did not update it. The charger works good with the factory included firmware.One major drawback is the fan, which is extremely noisy at full load, under medium or light load it emits a whining noise from the PWM frequency. The fan controller circuit should be improved, with a higer PWM frecuency, and quieter fan.