Did I learn something regarding low internal resistance of cells combined with resitance of light?
Let me explain. Experimenting with 3 Luminous SSR50 LEDs , direct driving.
Taking tailcap measurements, surprised to see 3 x IMR16340s deliver an initial 5.6Amps. Over a period of 15 seconds this drops to 4A. Had quite a few runs , recharging cells , all good.
When I tried 3 x IMR26650 , resting voltage around 3.9v I measured a steady 4A. With cells charged to about 95% , I measured a steady 5.6A. Tried several times , making sure I was getting good contact , 20-30 seconds and a steady 5.6A.
Here's where I think the lesson occurred. Using an FM 3x26500 body with a small spring in the tailcap to use as a twisty , (spring makes contact with retaining ring at top so very little resistance) LEDs started turning very blue within about 2 seconds. If they could handle 20-30 seconds at 5.6A with no colour shift , how much higher was the current without multimeter in circuit?
Then tried 3 x fully charged AW C LIOns. Steady 5.4A. I would have guessed after the IMR26500s , 4.5 - 5A from the AW Cs. (I was hoping for around 4.5A for the sake of the cells)
So I believe the lesson is to really get the benefit of IMR cells ( assuming you want maximum current) you need to have minimal resitance in the light as well otherwise the advantage of the low internal resistance of the cells is mostly wasted.
So am I stating the obvious?
As a result of this , if I was making a single cell DD SS50/90 light , say Mag 1C using Mag switch , with the high resistance of the mag switch I'd use an IMR26650 for the longer run.
If I wanted maximum output , I'd replace mag switch or chose alternate host with lower resistance and use an IMR26500.
FYI , also found with 2 IMR16340s I got just less than 100ma, with 3 primaries I got about 280ma - providing an unexpected backup option for a low powered light.
Let me explain. Experimenting with 3 Luminous SSR50 LEDs , direct driving.
Taking tailcap measurements, surprised to see 3 x IMR16340s deliver an initial 5.6Amps. Over a period of 15 seconds this drops to 4A. Had quite a few runs , recharging cells , all good.
When I tried 3 x IMR26650 , resting voltage around 3.9v I measured a steady 4A. With cells charged to about 95% , I measured a steady 5.6A. Tried several times , making sure I was getting good contact , 20-30 seconds and a steady 5.6A.
Here's where I think the lesson occurred. Using an FM 3x26500 body with a small spring in the tailcap to use as a twisty , (spring makes contact with retaining ring at top so very little resistance) LEDs started turning very blue within about 2 seconds. If they could handle 20-30 seconds at 5.6A with no colour shift , how much higher was the current without multimeter in circuit?
Then tried 3 x fully charged AW C LIOns. Steady 5.4A. I would have guessed after the IMR26500s , 4.5 - 5A from the AW Cs. (I was hoping for around 4.5A for the sake of the cells)
So I believe the lesson is to really get the benefit of IMR cells ( assuming you want maximum current) you need to have minimal resitance in the light as well otherwise the advantage of the low internal resistance of the cells is mostly wasted.
So am I stating the obvious?
As a result of this , if I was making a single cell DD SS50/90 light , say Mag 1C using Mag switch , with the high resistance of the mag switch I'd use an IMR26650 for the longer run.
If I wanted maximum output , I'd replace mag switch or chose alternate host with lower resistance and use an IMR26500.
FYI , also found with 2 IMR16340s I got just less than 100ma, with 3 primaries I got about 280ma - providing an unexpected backup option for a low powered light.
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