I was sent a pair of evaluation C4 chargers by MiBoxer for review. The Miboxer C4 charger is similar in appearance to other more well-known chargers like the Nitecore D4 and i4 and the Xtar VC4, VP4 and Dragon VP4+. It is about the same size as the Nitecore D4 and will charge different types and sizes of batteries ( Li-ion/IMR/INR/ICR/LiFePO4 from 10 to 26 mm in diameter and from 34 to 70 mm in length and Ni-MH/Ni-Cd C, AA, AAA, AAAA batteries) which encompasses most of the batteries youíre likely to need to charge. It is a four slot smart charger with a nice digital display and two user interface buttons, SLOT and MODE. These two control buttons are placed on top of the unit where they are easy to access. (the NiteCore's are on the side.) It is priced in the same range as the aforementioned chargers (save the Xtar Dragon VP4+ which is more expensive.)
Size vs. NiteCore D4
Where the MiBoxer C4 sets itself apart is in added functions, completely or partially missing from comparably priced chargers; battery resistance, battery capacity and li-ion over discharge reactivation
. These added functions are only available using slot number 4. When a li-ion battery is placed in slot 4, the C4 will first determine and display its internal resistance in mOhms before continuing to charge. If battery capacity is selected via the MODE button, the C4 will fully charge the battery and then fully discharge it (you can choose a high or low discharge rate) to determine capacity in mAh and recharge it fully to complete the function. If an inserted li-ion battery measures 0v (again, only in slot 4), the C4 will trickle-charge it. If the battery voltage rises to normal the C4 will switch to normal charge mode and if it does not after a sufficient period of time the C4 will display ERR and stop.
According to what I have read a new 18650 li-ion should have an internal resistance of less than 100 mOhms and a used-up 18650 will measure over 400 mOhms. An 18650 from a recycled laptop battery pack measured at 77 mOhms which is reasonable for its age and usage. I performed a capacity measurement on one of the Samsung INR18650 - 30Q 3000mAh batteries I use in my BLF A6 and the C4 measured it at 76 mOhms and 2648 mAh. I donít have any 0v batteries right now to test out the reactivation but Iím going to tear down some recycled battery packs and there should be some there to try. I'll report back when I get to try the reactivation function.
Another small yet nice feature is the included two-position adapter for small sized (10440 or AAA) batteries. It is sometimes difficult to get them to sit squarely in my NItecore D4.
I have read in another review that the MiBoxer C4 charges at a slower pace than say the Nitecore D4 but I put 2 of the LG 18650's from the recycled laptop battery in the MiBoxer C4 and in my NiteCore D4. All of the batteries were within a range of .05v (Sorry, I didn't note nor can I remember the actual voltage range.) The MiBoxer C4 was finished charging in 1:54 (hours:minutes) and the NiteCore D4 took3:52! The MiBoxer C4 Smart Charger is a great option with its added features at the same price as other digital chargers. In fact, it has replaced my Nitecore D4 as my charger of choice these days.
Thanks to MiBoxer for the review unit. I think they've definitely produced a winner.
Note: If you are advanced in age, as I am, you will need a magnifying glass to read the included, folded manual/instruction sheet. It's no different from what is normally included with flash lights but this time you'll actually need to read the instructions!