NiMh Batteries?
- Thread starter FrogBoy
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js
Flashlight Enthusiast
FrogBoy,
I'm not sure what "most" modders use. Probably CR123 and CR2 batteries. Not many torches out there use NiMH rechargeables. Ginseng used them in his Aurora project. TigerLight uses them. I use them in my TL high current battery packs, and Ginseng used them in his custom MagCharger battery packs, although the stock MC uses NiCd.
You don't see many NiMH torches for precisely the reason you bring up. Overdischarge NiMH and you get cell reversal and damage. The TigerLight manual simply tells you to turn off the light when it starts to dim. That's the common solution.
Willie Hunt sells some pretty small voltage regulators, especially for currents under 2 amps. They can fit in many lights, I would guess. In any case, his LVR3I can be set to turn off when the battery pack reaches a certain voltage, thus protecting the batteries from damage.
I'm not sure what "most" modders use. Probably CR123 and CR2 batteries. Not many torches out there use NiMH rechargeables. Ginseng used them in his Aurora project. TigerLight uses them. I use them in my TL high current battery packs, and Ginseng used them in his custom MagCharger battery packs, although the stock MC uses NiCd.
You don't see many NiMH torches for precisely the reason you bring up. Overdischarge NiMH and you get cell reversal and damage. The TigerLight manual simply tells you to turn off the light when it starts to dim. That's the common solution.
Willie Hunt sells some pretty small voltage regulators, especially for currents under 2 amps. They can fit in many lights, I would guess. In any case, his LVR3I can be set to turn off when the battery pack reaches a certain voltage, thus protecting the batteries from damage.
BatteryCharger
Flashlight Enthusiast
Keep in mind that the reverse charging problem isn't as bad as many people believe. Not to mention NiMh are CHEAP if something does happen.
See this thread:
http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Number=587085&page=0&view=collapsed&sb=5&o=365&fpart=1
See this thread:
http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Number=587085&page=0&view=collapsed&sb=5&o=365&fpart=1
In the worst case, a cell of 10% or lower capacity among a string of other cells and running down to complete darkness, cell reversal is a bad thing. In the more likely case that you have a set of cells that vary over no more than a 5% range (that's 100mAh on a 2000mAh cell), and you smartly turn off the light once you see it begin to visibly dim, it is likely never to become a problem. The first case is partially abusive use and that is under your control.
Also, keep in mind that cell capacities contain a little chemical reserve potential as protection against reversal. So, even if you do dim it out almost completely, the low cell is likely to be recoverable.
Overcharging (and the heat generated) is the more likely problem you'll face. Although, with a smart charger, this possibility is almost eliminated.
Wilkey
Also, keep in mind that cell capacities contain a little chemical reserve potential as protection against reversal. So, even if you do dim it out almost completely, the low cell is likely to be recoverable.
Overcharging (and the heat generated) is the more likely problem you'll face. Although, with a smart charger, this possibility is almost eliminated.
Wilkey
andrewwynn
Flashlight Enthusiast
i built a low-volt cutout that only used 1 active component and about 6 inactives incl. a couple pots (which could be replaced with resistors).. I 'cheated' in my design 'cause i had a reference voltage, but you could make a reference voltage with 1 more active component.
click here for circuit
click here for circuit
