Nitecore UMS4 Charger Question
- Thread starter DJ Colonel Corn
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Hmmm
Well, I'm not sure if that's what this charger is doing, or what !
However like I said at the beginning, with it set @ 2000mA per slot it's no faster then the UM4 @ 1500mA per slot.
That said, again, when I switched the mode to 3000mAh per slot, it read 2500mA per slot on the meter and charged about an hour faster.
This is a curious little charger !
I'll also note that it mistook my nimh battery for an li-ion, and tried to charge it to 4.2 volts.
Luckily, I noticed the reading of 1.6V and immediately shut it down. Battery was quite hot.
I avoided a potential disaster here.
Well, I'm not sure if that's what this charger is doing, or what !
However like I said at the beginning, with it set @ 2000mA per slot it's no faster then the UM4 @ 1500mA per slot.
That said, again, when I switched the mode to 3000mAh per slot, it read 2500mA per slot on the meter and charged about an hour faster.
This is a curious little charger !
I'll also note that it mistook my nimh battery for an li-ion, and tried to charge it to 4.2 volts.
Luckily, I noticed the reading of 1.6V and immediately shut it down. Battery was quite hot.
I avoided a potential disaster here.
OK folks
A kind forum member, @HigherStateD , in the thread Nitecore UMS4 Intelligent USB Battery Charger , has reminded me that Watt's Law dictates the forumula Watts = Volts * Amps.
Therefore, since the UMS4 can output 18 watts (4*4.2 leaves room to spare), it can charge two slots at 2000mA each.
Still unsure why then, the QC charger and Nitecore charger are both rated 3amps maximum, but that just shows my lack of understanding regarding electricity.
If anyone wants to chime in on why these units claim a 3A limit, I'd be interested to hear it.
Because at 18 watts, charging at 4.2 volts, it can ouput just over 4 amps.
A kind forum member, @HigherStateD , in the thread Nitecore UMS4 Intelligent USB Battery Charger , has reminded me that Watt's Law dictates the forumula Watts = Volts * Amps.
Therefore, since the UMS4 can output 18 watts (4*4.2 leaves room to spare), it can charge two slots at 2000mA each.
Still unsure why then, the QC charger and Nitecore charger are both rated 3amps maximum, but that just shows my lack of understanding regarding electricity.
If anyone wants to chime in on why these units claim a 3A limit, I'd be interested to hear it.
Because at 18 watts, charging at 4.2 volts, it can ouput just over 4 amps.
As I watch my um4 charge, the amperage doesn't stay at peak output through the entire cycle. As it aproaches terminal voltage, the amps drop. Nominal voltage is a better, that is to say, more accurate figure to use for the equation. It's like how beginning mech users should calculate based on peak voltage, but not for accuracy, but rather safety. Under load, the voltage doesn't stay at peak, so nominal gives a more precise understanding of what's actually happening.
Yes, I understand this, it lowers the charge as the batteries approach 4.2 volts.
Still, at 18 watts, the UMS4 is more than capable of charging @ 2000mA.
My question is why the devices have a 3A rating.
What is the Brand/Model of the QC Charger you are using?
And what are the Complete Output Specs for it?
I'm not quite sure where your confusion lies. The equation looks like this, at the point where the output of the charger is hitting the maximum output, as stated by nitecore:
Output of ac-dc brick is: 5v * 3A = 15w.
Output of charger with 4 full slots is 4 (3.7v) * 1A = 14.8w
So the output of the charger is below the threshold of tolerance of the adapter.
Where I Think the Confusion lies is that DJ Colonel Corn thinks that His QC Wall Charger is sending 5V @ 3 Amps (MAX) to his Battery Charger.
And that is Not what I think is going on.
What I think is happening is when DJ plugs his QC Wall Charger into the Battery Charger, the QC Wall Charger sends a "Handshake" and asks...
"Hi. Are you a QC Device?"
Then the Battery Charger replies... "I Sure Am!"
Then the QC Wall Charger says... "Cool! What is the Maximum Voltage you can handle?"
Then the Battery Charger replies... "12 Volts Please"
Then the QC Wall Charger says... "OK. 12 Volts coming right up"
And then the QC Wall Charger starts sending 12 Volts @ 1.5 Amps (or so).
Now, if the QC Wall Charger is plugged into a Non-QC Device, then when it Asks if the device is a QC Device, it gets No Reply. So the QC Wall Charge reverts to it's 5 Volt out put at a Maximum 3 Amps.
So all that Stuff about the QC Wall Charger having a Maximum of 3 Amps ONLY Applies when it is Outputting 5 Volts. And when the QC Wall Charger is Connected to DJ's QC Capable Battery, it Isn't. It is sending 12 Volts to the Battery Charger. And the 12 Volts is at 1.5 Amps (or so).
This is Also why you see the Dual Input numbers in Specs for the UMS4 Battery Charger.
Input
DC 5V/2A 12V/1.5A
18W (MAX)
The Battery Charger will use 5V @ 2 Amps Input if you plug an Non-QC Wall Charger into it.
But will use 12V @ 1.5 Amps Input if it is connected to a QC Wall Charger.
---
On the Battery Charger:
I can see why the Maximum Single Slot Amperage is 3 Amps. Because the Battery Charger really Doesn't have Single Slots. It has Two Set of Dual Slots. Or 2 Lanes each made up of 2 Slots.
And if the Battery Charger allowed 3 Amps to flow thru Both Slots in a a Lane, then that would Exceed the 18 Watts that the Battery Charger can handle.
JMO after a Restless night of Little Sleep. And perhaps Too Much Coffee.
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See, my thought is that it's similar to the confusion over amperage displays on most mods... It displays the coil side amperage, not the battery side. The 3A max of the adapter doesn't in anyway correlate to the 3.7v amperage of the two rails of the charger.
BTW - If DJ put one of these Inline USB Meters in between the QC Wall Charger and the Battery Charger...
... I feel Confident enough to bet @Mooch next Paycheck that it would read 12V @ 1.5 Amps (or so).
BTW2 - An Inline USB Meter is a Handy little Gadget to have.
Because it is Cool to Know how many mAh went into say your Smartphone when trying to Figure out if it is time to Buy a New Battery? Or is just some App(s) that is Sucking down the Battery Life.
damn, and I just charge my batteries in my nitecore q4 until the light flashes green. Charging wasn't fast enough ay one point, so my solution? I bought few new sets of batteries so now I always have some spare batteries charged and ready to go
Some of us push our cells up to, and recklessly past, CDR, so we like to monitor the health of them, as CDR drops as they age. I think the intent of the OP, however, is to make sure the charger they paid good money for is actually capable of it's claims.
I totally understand. This was more of a joke on my side- I'm partially too lazy to go into so much detail about batteries/ chargers (mainly due to price- If batteries were expensve i'd really explore the topic), and partially not concerned too much as I use only regulated mods, so chances of blowing up the batteries for me are rather small. If I was a mech user my approach would be totally different
The battery market being a grey market, and regulated mods only being as good as the engineering, I prefer to monitor the health of the 20700 30A 3000maH cell or two I place so close to my mouth. I also check the tires, signals, breaks and such before driving.
Again, I totally understand. Thanks to this forum and my own online research, I managed to get my batteries from a trusted vendor.
I wasn't saying that i completely ignore battery safety- I check wraps, I am aware of Mooch's recommended CDR, and I never go past or even up to for the batteries I have.
The only exception for me was the AVB Avatar 21700 battery by Eleaf (?), that I treated like the values provided by the manufacturer were correct. Which I soon found out to be wrong with ECF memebers' help. But my mod didn't blow up
I have a few from XTAR but my are rated at 4.5-6.0V 0-2.5A. I also don't have a QC wall charger.
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