Charging voltage and cables

Hi All
I’ve noticed that many of us have experienced watch failures and it seems many of the failures are from over charging the battery over night. So we are learning from our mistakes but I have some questions. What is the optimum voltage to charge with? I’m using an older cell phone charger which is at 5volts 2.1 amps. Does anyone use a timer to prevent over charging?

Apparently it doesn’t matter because the watch has a built in voltage/current regulator. I think you are golden at 2 amps and 5 volts.

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Hi Louis
Not sure but I do know my Thor Pro did not like a “fast charger”. The watch gave me a warning in the screen…

I do use a timer. I set it to 2 hours then left it and went to bed. This simply because it’s really hard to find a spare battery for my thor pro 3g. I use 5v 1A adapter

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This is weird. Watches, just like phones, have the charging circuitry inside, that will stop charging the battery after it’s full.

Charging voltage should be arround 5v, the amperage should be self regulated internally, but in any case, I would recommend using a 1A or less charger for small batteries.

Batteries are typically charged at 1C. For example, if we have a 500mAh battery, 1C = 500mA, so if your watch has a 1000mAh battery, the sweetspot is a 1000mA (1A) charger.

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I’ll try to measure it with ampere meter whether the watch circuit will stop charging once it reach 100% or else. Might be on this afternoon (the next 6 hours) once i’ve done testing my thor pro endurance with Bluetooth and wifi on, which has been 1 day 19h 25m since the last charge, and still got 28% left

I have to respectfully disagree. My Thor Dual is maybe 6 months old and I charged it nightly for 6 to 8 hours and the battery died and swelled, breaking the back and frame. I don’t want to have to buy a new watch every six months…

I’ll be darned. Must be better to use 1 or 1.5 amps then, thank you!

As you can see, the thor pro 3g charging current is about 1A.

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A bit too high for me… Do you know the battery capacity of your watch?

500Mah battery capacity

So it seems the charging current stop once it reach 100% , and the voltage reading was stay at 5 volt. This measurement was on zeblaze thor pro 3g, i can’t tell for sure it’llbe the to any other watch.
Still i won’t suggest all night charging to anyone, including my self :slightly_smiling_face:

For 500mAh capacity, the perfect charging rate is 500mA

As I have posted in the past I use a power meter to monitor the charging of my watches. It takes all the guess work out of what is actually happening and helps spot potential problems. I tried several and this is the best one I tried for one because of its easy to read multiple screens.
It gives you the basic voltage, current and the amount of current transferred in an easy to read format. It is also BT so you can read the info in the app on your phone. In this instance it is connected to a 2A charger and will normally show when the charge is complete, if the watch is off. As you can see here with my Lem7, just because you use a 2A charger does not mean it puts out 2A. The internal regulator controls the amount of charge current. If you were to notice it was taking a higher than normal charge current it could be an indication of a problem with the charging circuit.
You can compare the amount of charge the battery received and compare it to the status when you started. You can’t theoretically overcharge a device as long as the internal charging circuit is working properly. A way to monitor the charging circuit will help in protecting your investment. I bought this meter on Banggood for $20.


Yes indeed! It seems to follow also that it would be better to utilize the current regulator of the charging device rather than relying on the current limiter in the watch, producing more heat in the watch. I am certain that the watch uses a taper charge as well.
Charging Rates

Batteries can be charged at different rates depending on the requirement. Typical rates are shown below:

Slow Charge = Overnight or 14-16 hours charging at 0.1C rate
Quick Charge = 3 to 6 Hours charging at 0.3C rate
Fast Charge = Less than 1 hour charging at 1.0C rate

The charge rate of the watch is predetermined by the manufacturer’s algorithm. I am certain that it is a taper charge starting at the 1.0 C rate, irregardless of the supplied charge current.lithium_charger

BTW… has anyone noticed that the cracks in the back-plate seem to be forming/originating from the pins in the watch? I wonder if it is heat related. If the pins produce a relatively high resistance at the contact points or of themselves, the current regulators will respond by trying to increase the current value, possibly producing more heat. KEEP YOUR PINS CLEAN! (alcohol pad)

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So coooool! Me wanty! How does the temperature indicator work? Does it have a probe port?


. I figured it out. There’s an app for that!

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Why charge at night !? This is not convenient because a signal sounds on my watch when charging is complete. Firstly, they charge not so long, and secondly, the signal of the end of charging will interfere with enjoying sleep.

Now thats a first . I always switch off and charge at night ? No beeping as its turned off ? What are you using and do you leave on while charging …

I fix phones at work…Apple and Samsung. Many phones seem to not shut charging down when the battery is full. We fill a 5 gallon bucket full if swollen batteries every couple of months. Both of my Zeblaze watches also had swelled up batteries.

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