Charger Miller ML105 V1.0





This charger is a very small 26650 charger, it needs an external USB power source.



There was no retail box for the charger and the only accessory was a polishing cloth for the clear lid.



The charger has a micro usb connector for power input.



The charger has space for 3 leds, but only two of them works.
The red one will show steady light when charging.
The green one will show steady light when done.
Without a battery in the charger the leds will alternate fast.



This looks like space for usb output, but the charger is not equipped with that.




The led has no hinges and must be removed to charge 26650 batteries.



The battery slot is nearly fixed length, but behind the metal box at the back there is a spring, this allows some variation is accepted. Length must be between 64mm and 69.6mm, this means some protection cells will not fit.





The charger can handle all unprotected 18650 and 26650 and many protected cells.
It is possible to charge some smaller IMR (high current) cells on this charge by using a spacer, but check the charge specification for the cell first.



Inside the charger



The charger is easy to open, only four screws must be removed and it can be pulled apart.



There is not much electronic in the charger, only a buck converter for handling the charging and a couple of transistors.
There are two leds in this charger.



There is nothing on the bottom, except the type number and version.





The charger has been prepared for more leds, it has 3 light pipes.



Measurements

• Below 0.5 volt the red/green leds will alternating fast.
• Above 0.5 volt the charger will start slow charging with about 45mA, red/green leds will alternating slow.
• Above 2 volt the charger will increase current to 0.13A and only the red led will be on.
• Above 2.5 volt the charger will start regular charging and only the red led will be on.
• Without a battery the red/green leds will alternate fast.
• The charger will restart if battery voltage drops below 4.10 volt.
• Charge will restart charging after power loss, or battery insertion.
• When not connected to power the batteries are drained with 0.08mA
• With a full LiIon cell the charger will drain the battery with 0.05mA
• This charge will not be able to reset battery protection.

The charger has a nice CC/CV charge curve.





No problem charging 18650 with 2600mAh and 3400mAh either.



A 26650 is also charged fine.



An older cell makes the charge circuit a little bit unstable, but the cell is charged fine.



Adding 0.5ohm in series with the usb power supply to simulate a long cable or weak supply did not present any problems.



M1: 28,0°C, M2: 30,6°C, M3: 27,4°C, HS1: 32,7°C

There is not much heat in this charger.



The charger is a dumb charger, i.e. no microprocessor that needs to initialize or anything, when power is applied it will start charging immediately. This type of charger works perfectly with a solar panel.



Conclusion

The charger is a good charger and with the spring in the back it can handle many xx650 cell, both protected and unprotected (Very long protected cells will not fit).
The charger current is a bit above 1A, this is fine for most 18650 and all 26650 batteries, but a bit high for old 2900/3100mAh cells, if you have many of these cells and want to make the last as long as possible: use another charger. For other cells: enjoy the faster charging.



Notes

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