Question:
Checking the first of my two v7.1 chargers
— cell voltage does continue to go up, for at least several hours after the green light goes on (4.22v after a couple of hours)
— with no cell in the charger — green light stays on — I measure 4.54v between the charger’s terminals on my voltmeter.
Does that make sense?
Is this good enough? Btw, power doctor is spot on, changing between 0,01A and 0,02A after “cut off” so I guess mine is calibrated properly.
1. Normal charging - red light
2. Still charging - green light 4.17V
3. Still charging - 4.20V
4. Still charging - 4.22V
5. Self discharging (power source disconnected)
Well, that is a hell of a USB doctor isn’t it? 
Frankly I don’t know… all I can say is that my unit finished charging this morning at 4.17. Now (+7 hours) reads 4.16. In “real world” scenarios that is not overcharging. But will see what it says after some more time (Battery is 4.35V so I do not worry too much)
My setup is quite simple:
Do you power that meter of the battery?
A real DMM is much better to use.
Checked the second of my two v7.1 chargers.
Same behavior: green light comes on at 4.15v
Voltage continues to be supplied (first one measured 4.54v, second one measures 4.51v) with green light staying on
Voltage of cell continues to go up — haven’t let one go above 4.22v (Samsung cells)
When the cell is removed, the green light stays on and the terminals of the chargers stay at 4.54/4.51v
No, the voltmeter receives power from the measured poles. It needs uses about 10mA according to specs. I am sorry but I don’t have a DMM. I could remove the meter and check at different times but, still, I don’t see how this could change things much. Do you think that the voltmeter is absorbing the trickling charge so the battery does not overcharge? - if that was the case there would be a very simple fix for the problem. (see post #5)
With about 20mA trickle charging the meter is eating half of that. It would be better only to connect when checking.
^ Hmm, Could that be a sort of a work around? Hook up a couple voltage meters. Would it interfere with the charging algorithm?
Last night I popped a partially discharged Samsung –28A laptop pull into the ML-102 v7.1 I acquired in late November. When I checked on it this morning, the green light was lit. My USB meter wasn’t reporting any drain, and my multimeter shows the cell voltage (cell still in charger) as 4.176v.
You would have to match the current rather well for it to work. To low current and it would still charge, to high current and it would discharge the battery.
repeating the question, is this the expected behavior?
on my two v7.1s, after the green light goes on
— I remove a cell from the charger,
— the green light stays on, and
— my meter measures over 4.5v between the charger’s terminals
Chargers may behave this way, without any problems. The issue is how much current can be produced above 4.2 volt, 0.1mA is no problem, 20mA is a problem.
> how much current can be produced
Ok. So I took the meter, set it for
DCA, 200mA
and measured between the terminals (green LED on)
Meter said “overload” then went to zero.
DCA measurement stayed at zero
DCVolts stayed as before around 4.5v
Unplugged the power input; plugged the power back in
Got flashing alternating red/green/red/green
So — ?? — something reset there? I have no idea what the alternating red/green LED is supposed to be signaling.
After a while, I put the cell back in, LED changed to solid green, and it’s back to its original configuration, still charging.
Oops, you need a new fuse for you DMM.
You measured to zero, you should have had the battery between the (in series with) DMM and the charger.
That is normal behavior. Green & Red light flashing: Battery not detected
> That is normal behavior. Green & Red light flashing: Battery not detected
So — it should do that whenever the battery is removed?
Because I’ve never seen it before.
That’s why I’m asking what’s normal — since I see the green light staying on when the battery is removed.
EDIT — fortunately I have spare fuses for my meter.
Duh. I’ve done this before.
It is more likely because the battery voltage is around 0 and not raising due to the shorting with the DMM.
Many chargers signals faults with flashing leds.
LED status light:
Red: Charging
Green: Fully charged
Blue (dim): Ready and not connected to any device
Blue (bright) solid or flashing: Charging external device
Green & Red light flashing: Battery not detected
Never paid much attention but the flashing is normal when you power the unit without battery. After charging a battery, the LED stays on (with or without battery) until you reset power or reinsert a battery
I shorted the DMM set on amperage, and it quit measuring amps til I replaced the fuse.
But it still measured voltage; the charger was still supplying the 4.5v.
I see what happened.
I’d never tried unplugging and plugging the DC power back after removing the cell from the charger.
Power cycling the charger resets something — here’s the pattern:
—- I remove the cell, the green LED stays on
(and if I put the cell back in, the green LED stays unchanged)
—- with no cell in the charger, when I unplug the power and plug it back in, all three LEDs (red/green, and blue) start flashing
That’s true for both of the v7.1 chargers I have.
So it detects “no cell in charger” only after its DC input power has cycled off and on.
I’ve always left the charger plugged into its DC power throughout testing — so I never saw this before.
—————————————-
Reformatting Iker’s list above:
— Red: Charging
— Green: Fully charged
(I see the green staying on after a charged cell is removed, as long as input power is provided)
— Blue (dim): Ready and not connected to any device
— Blue (bright) solid or flashing: Charging external device
— Green & Red light flashing: Battery not detected
(I see red/green and blue all flashing )
And now the voltage is 4.18 something. Clearly my example has this problem as well.