XTAR was kind enough to provide me with two of their 21700 batteries with 5000 mAh nominal capacity for a test.
You can get it straight from XTAR with this Link
Here are a few manufacturer specifications about the batteries:
| Manufacturer | XTAR Technology Inc. |
| Model | 21700 5000 mAh |
| Size | 21700 |
| Dimensions (⌀ x length) | 21,5 x 74,5 mm |
| Weight | 70 g |
| Positive terminal | Button Top |
| Battery cell | Samsung INR21700-50E |
| Nominal capacity | 5000 mAh |
| Protection circuit | Yes |
| Max. constant discharge current | 10 A |
According to XTAR, the batteries contain a high-quality Samsung INR21700-50E cell, which should speak for a high quality and service life with good treatment. However, I did not remove the wrap to check this.
Additionally, they are equipped with a protection circuit against overcharge, short circuit and deep discharge. This results in relatively large dimensions of 21.5mm in diameter and 75.2mm in length (including button top). Because of this, you should make sure that the battery is compatible with the flashlight in which it will be used. In my case, it fits the Acebeam L18 and L19 and Sofirn SP35. In the Wurkkos DL10R and HD20 it does not fit.
Here is a comparison picture with the unprotected Sofirn 21700 4000 mAh:
The maximum continuous discharge current is specified at 10 A. At least my Acebeam L19 ran with its maximum just under 9 A without problems with the XTAR battery.
You can charge the batteries without problems with 3 A (= 0.6 C) without them heating up excessively.
I tested the capacity of the batteries with the Vapcell S4 Plus at a discharge current of 1 A. This had resulted in a capacity of 5029 mAh and 5036 mAh for the two batteries, respectively. The manufacturer’s specifications are plausible, as expected from XTAR.
*Conclusion: Excellent batteries that deliver what they promise. :+1:
*
In order to be able to quickly recharge the batteries, I was supplied with the XTAR SC2 Quick Charger.
It’s available Here
This is a simple and really compact dual-slot quick charger. With a QC3.0-capable power supply, it charges a single battery with up to 3 A and two batteries with 2 A each. The charging current is only limited by an internal resistance measurement. So you should only charge batteries in there that can handle such a high charge current. According to the manufacturer, it is suitable for 18650, as well as 26650 and 21700 batteries and all sizes in between. Protected and accordingly long 21700 batteries fit in perfectly.
The charging port is an out-of-date Micro USB port. Each slot has four LEDs to check the charge level.
*Conclusion: Super compact fast charger, unfortunately with Micro USB and only suitable for batteries that can tolerate high charging currents.
*