Here is the emoli solution. I use 5761 on emoli, 26700 but the voltage is the same. Problem is 5761 is touchy and varies between lots on voltage and size acutally. NTCs are also very variable with a very wide tolerance of 20%. Using the 26700 I get @ 30 minutes run time and 10-12 minutes to full charge at 5A with a BC-6. Took a lot of work to do it.
Using an NTC ?
post #25
http://candlepowerforums.com/vb/showpost.php?p=2634123&postcount=25
I chose the emoli because I was able to get right up to the flash point with the method described and gained about 50-80 lumens more, that can be up to 10% brighter. You can use two A123 but they reach 6.9 Vbattery (rated 3.3V nominal voltage) and about 6.6Vbulb when used and can be direct drive. Good combinations but you can get 10% more lumens by pumbing 0.4-0.5 volts into the bulb.
The NTC gives the soft start but steady state voltage was too high. You cannot use NTCs in series and parallel, the result is unpredicatable due to the fact NTCs work off heat that is a result of Amps going through it. You change that with added or reduced resitance. So with one of the prescribed NTC s leaves too much voltage after steady state, and I mean that is measured it 10ths of volts. So you reduce the steady state with a resistor, Ohms Law. You must take the voltage readings from the light, not a test fixture, and Vbulb right at the pins. Buy a few bulbs. You will burn a couple while fine tuning to the edge like I did. See the thread it will get you a starting point.
Another very bright 5761 I build was unexpected. I used two D lithium batteries. The PCBs on them are junk and would not work, could not start the circuit. I bought PCBs from batteryspace.com and made a 7.2V pack and those also take care of balancing for series charging so I shuved it into a MagCharge. Undexpectedly the PCB somehow acts like a softs start. It must just start up slow enough to do that.
Another M*gCharger 5761, but why
Both these lights are the brightest 5761s I have built and if you searched the 5761 key word, you see I have done a few. The emolie is a good choice but will take some work to get there.
Someone, QUICK! give us a regulator!!
Ok, how do you spell it: emoli? emolie? e-moli?
We need a regulator for sure.