Anyone using 10440 batteries with an LPC?

[madmatt]

I have just recently finished two 3405 mxdl builds, a phr and an lpc, jayrob heatsinks/rkcstr v3 drivers.
Both lasers work nicely but I am having trouble with the battery life of the 10440s (600mah:crackup. I am using 2 batteries and a dummy battery (bolt) for around ~8.4 V full charge for the lpc, running @420ma. The phr is running @110ma and using 3 batteries and a diode to drop voltage to ~12V max.

So far I have got maybe 1 hour or so total run-time from the phr (1-1/1/2 min duty cycle) before it needed a recharge (current dropped to ~50ma).
The lpc is much worse, and will run about 1 min max on 2 fresh batteries before current starts to drop off, slowly at first then faster. Several of the 10440s (I have 6) seem a lot worse and only can sustain 420ma for maybe 15-20s before dropping down to <100ma.
Just wondering what sort of run times others using 10440s with an lpc are getting?

Edit: Just ran some tests on the batteries I had been using in the phr. I hooked up a ddl driver set @ 400ma and a 4 diode test load, one multimeter measuring current from the test load and one measuring battery voltage, which was 12.63V originally. I ran the test on the fully charged batteries for 33 min, when the voltage of the batteries had dropped to ~8.3 (~2.75V each roughly). Current was stable @ 399-400ma the whole time. Better than the the batteries I was using in the lpc but that only comes to around 220mah i think. Will test the others tomorrow...

 

[ndrew2505]

if your using trustfire batts then you should know they are notorious for over-rating their batteries. what they rate at 600mah may only be 200-300mah...

 

[dr-ebert]

The rated capacity assumes a discharge rate of 0.1C, which for a 500mAh battery means 50mA. The usable capacity can drop sharply at higher discharge rates.

A Li-ion cell has a 4.2V charging cutoff, meaning you must not charge it to a higher voltage, otherwise it will be damaged. The voltage then settles down to 3.6..3.7V, which is the rated voltage. Discharging the cell to below 3.0V will damage it as well - which seems to be what you've done. See for example here.

 

[madmatt]

Thanks for the replies.
I just tested the other 3 the same way, 400ma DDLl/4 diode load. Initital voltage 12.3, on switching the circuit on voltage dropped to <8V within 1 minute and current also dropped way down quickly too. So it would seem I have 3 damaged/faulty batteries.The charger says they are fine but they are only 4-4.1 V after a full charge. Time to order some more I guess, at least they are cheap...

Out if interest I tested some Trustfire Grey 16340/RCR123As from my flashlight, they put out ~400ma for 1h 45m before the voltage got too low, ~700mah which is still overrated (meant to be 880mah) but not too bad.