Got a nanjg110 , for a single mode 1x cr123 light, with an xml2-t6
It should deliver arround 950ma to the led, but how much would it draw at the tailcap? On a single cr123 i measure almost 2.2a, ain’t that a little high ?
Since it’s only a single battery, the difference in current (2.2 amps - 0.95 amps) has to be going somewhere. Either that, or maybe your meter leads.
How are you measuring the emitter current? Are you using a clamp meter, or do you have the meter in series with the emitter?
How are you measuring the tailcap current - what are your meter leads like?
Well haven’t measured led amps, only tail, in series, the leads of my meter are okay, pretty descent set (voltcraft)
Measruing a nanjg 105c with 5x7135 and a 18650 gives me measurements of little over 1.5amps on tail on high mode, and 500mah on med, 0.2mah on moon.
That seems to be on par with what i expected.
Isn’t the nanjg 110 a buck circuit…as in conversion of the power from the battery to the emitter, they are rarely efficient
I think HKJ did a review on it…
Hi,
I mis-read your OP - I thought you had said that you were MEASURING 950 mA at the emitter - sorry.
According to this:
So, if I had to guess, with a CR123, you’d probably see about 2.2 amps at the emitter?
EDIT: If that is the case, you might as well just get a contact board and wire the battery /- leads directly to the emitter/- leads since the driver is single mode?
Convert everything to watts to make sense of what a boost driver is doing. To get an accurate idea you'll need to measure both the input voltage, and output volts & amps.
Well i think i understand how a boost driver should work , to make more volts to deliver to the led it will use higer amps to do that. (Thats where coverting to watts kicks in)
Just at 3.1 volts 2.1a seemed little high to me, due to the fact it should only deliver 950ma to the led. Just cant find how much volt it should deliver…
I even tried 3x aa (eneloop) so it has 3.6 volt, and even the it uses 2.1 amps.
Lowerig to 2 eneloops at 2.4 volts still lets it such 2.1 amps.
Measuring volt at the led gives me a very strange readout of only 0.345 volt, running 2x eneloop (2.4 volts)
It's not strange, it's just flat out wrong. A LED won't even come close to lighting up at only 0.345v. Measure between the two wires that go to the LED star/board/MCPCB/whatever the LED's mounted on.
That driver is not made to run from three AAs. And I think you're guessing about the input voltage... they aren't an actual 1.2 volts, and they for sure won't be at that voltage while delivering 2 amps. The open circuit, no-load voltage isn't even the one that matters. What you need is the actual input voltage while the light is running. Multiply that by the input current, and you have the input power, in watts.
If you take the same measurements on the output side, and do the same math, you get the output power in watts. Input minus output equals the driver efficiency. Without all those numbers, or even with all but one of them, we're all just guessing.
I measured the cells today, are 1.21 and 1.25 together that would be 2.46
Under the load of the nanjg 110 that value drops to 1.66.
That measurement of 0.345 volts at the led, i did measure again today now it comes to a more sensible 2.77 volts with 1 eneloop, slightly going up to 2,84 with 2 and 2.95 with 3 eneloops.
Did a measurement again on the amps, it does draw 2.2 with the 2 eneloops, wich, under load deliver 1,66 volts to the led.
Had no option to measure the amps at the led, the led and driver are stuck in the dropin, im afrraid that desoldering a lead from the led woud make it almost impossible to solder it on again
But the 1.66 volts beeing upped to 2.84 makes more sense in drawing 2.2 amps to me. never thought of the voltage dropping that much under load.
When I look to the HKJ review, and the 2.2 amps would be on par with an input of 1.66 volts. 8)
I thought these voltages were the standard battery voltage, not voltages under load.
After (again )reading how hkj tests i see he measures the input of the voltage so it must be under load.
So i did the test again with 3 eneloops, 3,81 volts without load.
Under load voltage drops to 3.3 volts and the amps drawn from he batteries is 1.1a.
Voltage at the led is 2.97.
So there is no problem….
My expectations were based on some assumptions i made :~
Remember, failure is always an option (Adam Savage) :bigsmile:
So imagine what happens to the input current with two AAs when the voltage gets down to around 1v each... yikes. :O
On a single AA/AAA it reduces the output by about half so the input current stays reasonable, but above 1.8v/2v it tries to do the full output current.