Quark AA Current

[glockxj]

Can someone measure the current at the tail of their Quark aa? Does 800mA on a 14500 and 1.2A on an eneloop sound right?

 

[think2x]

I don't have any 14500's but My daughters did 1.4A on ONE Nimh.

 

[GeoBruin]

I'll let you know once I get home. My Quark of course is with me but my DMM is not.

 

[glockxj]

I just thought it would pull more current with the 14500 than with the eneloop.

 

[hellokitty[hk]]

No it has to boost the 1.2v+ of a NiMH up to the vf of the LED ≈3v+.
So if you're measuring at the tailcap, you'll get what the driver is pulling out of the battery, which will probably be about three times as much as the emitter is seeing.
If you measure it at the emitter, you'll get the actual amperage to the emitter, but that could be problematic.

 

[glockxj]

No it has to boost the 1.2v+ of a NiMH up to the vf of the LED ≈3v+.
So if you're measuring at the tailcap, you'll get what the driver is pulling out of the battery, which will probably be about three times as much as the emitter is seeing.
If you measure it at the emitter, you'll get the actual amperage to the emitter, but that could be problematic.

Thanks for your reply. Since the 14500 is 4.2 volts fresh off the charger, the driver has to pull less current from the battery, correct?

 

[hellokitty[hk]]

vf is the voltage required by the emitter, and it's a bit over 3v for that LED.
So yes for the 3.7v~4.2v li-ion, the driver just needs to buck down the voltage a tiny bit, and supply the proper amperage.
For an equivalent mode using a NiMH (1.45v hot off the charger), it has to draw more power to boost the voltage up to 3v+, and there are some driver inefficiencies too, so it's got to pull a higher amperage from the battery.

IMO those readings look fine, but I don't have a quark, nor do I know how much current they're driven at.

 

[glockxj]

Thanks for your clearing that up for me. It also answers other questions I had. All your help is appreciated!