Battery Charger Frequently Asked Questions

Battery Chargers FAQ

The charger has finished charging my battery, but the display is telling me there's significantly less mAh than the battery is rated for. Why?

    • A basic charger will only tell you how much mAh was put in during the charging cycle. It doesn't include any charge that was already in the battery.  So for example, we ship our batteries at about 30% charge, which means that these chargers would read 30-40% low.  Most chargers are this way, including the XTAR VC2 and VC4,  the Nitecore chargers that have a mAh readout, and many others.
    • Only some high end chargers can actually run a test cycle that will discharge the battery first, and then charge it.  Some examples of chargers that can do this are the Opus BT-C3100 or XTAR Dragon VP4 Plus.  Please note that even with these chargers, in order to not damage the battery they do not fully discharge the battery all the way so they will still usually read a little bit low, but they should at least be close (for example maybe 2800-3000mAh in a 3000mAh battery would be a reasonable expectation).

My charger isn't charging my batteries all the way to 4.2V. Why?

    • For a lithium ion battery, all of the chargers we sell are rated to a certain tolerance around 4.2V.  Electronics that would charge to exactly 4.20V every time would be much more expensive than the price range of the chargers most consumers would buy. Most will be within about 1% and this tolerance is usually in the specification.
    • Over charging batteries is extremely dangerous and should be avoided.
    • Most high quality consumer grade chargers should charge to the 4.12-4.21V range and this is perfectly normal.
    • Research has shown that under charging your batteries, on the other hand, can actually lengthen the life of the battery. You don't get as much capacity/runtime, but generally it is negligible and most folks find it worth the tradeoff.

I charged my batteries and the charger gave me a voltage reading of 4.xx. I then measured them on a different charger/voltmeter/multimeter and they were different. Why?

    • The voltage reading given by most chargers is not an exact measurement, and can be affected by many factors, including whether the battery is properly placed in the charging bay.
    • It is normal to see small differences when reading voltage on a battery using different methods.
    • For example, one charger may read 4.19, and another may read 4.15. This is approximately a 1% difference, and should be considered within a normal operating tolerance.
    • *Voltage reading/tolerance specifications are generally not provided by the charger manufacturer and these numbers are for reference only.

Can I charge other battery types (chemistry) with my charger?

    • Some of the chargers we sell are compatible with Ni-Mh/Ni-Cad batteries. Please be sure to read the product description!
    • If you are not sure, please refer to the manufacturer's website.

Can I charge primary lithium batteries with my charger?

    • No.  Primary lithium batteries are not rechargeable and are very dangerous to attempt to charge.  Be careful that you only try to charge lithium ion rechargeables.

    How do I know which lithium ion battery charger to use with my INR/ICR/IMR/etc battery?

      • All of our chargers will work with all 3.6-3.7V lithium ion battery chemistries. The only thing to be concerned with, when shopping for a charger that will work with your particular battery, is whether it fits that battery size. (For example, an 18650 battery, or a 26650 - that is the battery size).

    Which charger is fastest?

      • We offer a range of chargers with different charging speeds.
      • Most chargers offer accelerated charging in a limited number/location of bays. For example, a 4 battery charger may only be able to handle 2 batteries at 2A or four batteries at 1A.
      • We try to communicate these limitations on the product page but please see the manufacturer's site for more information.
      • Right now, the absolute fastest charger we have is the Vapcell S4 charger; which can do 3A charging.  We also carry many chargers that can do 2A charging.
      • Be sure to see the below question about the ramifications of using fast charging speeds.

    What charging speed should I use for my batteries?

      • Slower charging speeds are always easier on the batteries and will lead to more cycles before they wear out.
      • You can check the battery datasheet for a standard charge speed.  Usually you can get pretty good life by using this charge speed, although you can still increase it by charging even slower when you have the time to wait.
      • Many battery datasheets will list a "fast charge" or "rapid charge" number.  This can be used safely if you are willing to lose some battery cycle life.

    I plugged my USB powered charger into my computer/into an adapter, and now I can't use the fastest charging speed (1A, 2A, etc.) Is my charger broken?

      • Most likely, your charger is fine. There is probably another reason why you aren't seeing the full charging speed from your charger.
      • There are a few reasons why this happens:
        • You should only use the USB cable that came with the charger. Other USB cables can slow charging down by limiting current.
        • You charger can only charge a certain number of batteries at the highest speed, and only if they're in the right spot in the charger. Refer to the owners manual. (For example, most 4 bay chargers that are capable of 2A speed can only charge 2 batteries at that speed, and only if they are put in the right spots).
        • If plugged into a computer or adapter, the port/adapter is probably not able to supply enough current. See our explanation below regarding how to make sure you select an adapter/port with enough current.
      • In order to use your charger at its full capabilities, you cannot use an adapter that provides less than the amps (A) that your charger requires - but you can always choose one that provides more.
      • A charger that requires up to 2A power, can use a 2.1 Wall Adapter.
      • Example 1: XTAR MC1 Plus requires 1A power. It can use a 2.1A power adapter.
      • Example 2: XTAR VC4 requires 2A power. It can use a 2.1A power adapter.
      • Example 3: XTAR Dragon requires 3A power. It CANNOT  use a 2.1A power adapter (it comes with its own 3A adapters).

    Does my charger have a warranty?


    If you have any other questions, feel free to contact LiionWholesale here.