Test/Review of Charger TrustFire TR-005

Charger TrustFire TR-005






The TrustFire brand covers many different flashlights, batteries and chargers, but usual the quality is a bit low. Here I am testing a single channel LiIon charger that can charge batteries up to 26650 size.



The charger is sold in a cardboard box. The package lists the specifications and supported battery sizes.



The box contained the charge, a mains cable and a instruction manual.



The charger has a universal mains input (110-240VAC 50/60Hz).



The charger has a small switch to change between 3 volt and 4.2 volt charging, or more correctly between 3.6 volt and 4.2 volt charging.
The switch is very discreetly placed and there is no indicator on top of the charger to show what is selected, this is not a very good solution.



The charger has a led to show the charge status. As usual red is charging and green is finished (More or less).



The charge slots can handle from 30.5mm to 72.3mm long cells, including flat top cells. The slider works fine.





The charge current is too high for normal 16340 and 14500 batteries, but can be used for IMR 16340/14500 batteries.
The charger can handle 70 mm long batteries, inclusive flat top cells.



Measurements

  • In 4.2V mode the change betweem red and green led is at about 4.2 volt.
  • In 4.2V mode the charger will stop charging at about 4.23 volt
  • In 3V (LiFePO4) mode the change betweem red and green led is at about 3.5 volt.
  • In 3V (LiFePo4) mode the charger will stop charging at about 3.9 volt
  • The charger will restart if the battery voltage drops, battery is reinserted or the power cycled.
  • The charger will charge from 0V with about 1.4A, the current will drop with raising voltage.
  • Without power the charger will discharge a battery with about 0.7mA





The charger does not use a CC/CV algorithm, but is more like a constant voltage with a series resistor. This means high current when starting the charge, but it will soon drop, making the charge time rather long. This part is fine for the battery.
When the battery is full the charger will not stop charging, it does just change the led to green, but continue to charge, this will wear the battery down, if the user does not remove it within a few hours after the finish light turning on.



A 3400mAh cell is slower.



The 2600mAh cell needs a higher charge voltage, during the charger. This means lower charge current and longer charge time. It takes longer to charge a 2600mAh cell than a 3100mAh cell!



My old 16340 cell works fine with this charging algorithm.



When starting charging the current is rather high and the temperature will raise a bit.



M1: 45,1°C, M2: 56,7°C, M3: 66,8°C, HS1: 92,9°C
The charger has a very hot spot on the plastic.



When power is turned on the charger starts charging immediately, there is no microprocessor that needs to do some checking first.



LiFePO4 (IFR) charging

Switching to 3.0V charging, the charger can be used for 3.2 volt LiFePO4 cells.



The charger reports battery full a bit to early, it does not stop charging but continues to charge the battery beyond the full voltage.


The charger passed an isolation test with 2500 volt, but failed a 5000 volt test, this makes the charger acceptable for 110VAC usage, but doubtful for 230VAC usage.



Conclusion

The charger will charge the cells, but it is rather slow and the missing termination is not very good. I do not like the very discrete switch.



Notes

Here is an explanation on how I did the above charge curves: How do I test a charger

I did this review some time ago, but did not got around to publish it before now.

Thanks for the review! Does the failed 5k V test mean that the charger does not live up to the CE markings printed on the box?

With 90% probability: yes (My test voltage is a bit to high, the correct values to uses is 4.2kV, but my tester do not support that).

With all the usb chargers I have tested, I have not seen one fail the 5kV test, without seeing some other problems inside it when I tear it down. One very common reason for the fail is to use a 1kV capacitor between mains and low volt side, this must be a 5kV safety rated capacitor to pass the CE marking. Another reasons is too short distances between mains and low volt side.