AW's C Lithium Ions

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beetleguise

beetleguise

Enlightened
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Jun 12, 2007
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I am powering a 2c mag61 with AW's c lithiums and am experiencing trouble with the light shutting off after about 5 minutes on "high". I just pulled out the batteries and found one at 3.65 V and the other at 3.1 V. When I started out tonight they were both at 4.07 exactly.
My theory is that the 5761 is too hot a bulb, and the discharge rates of the batteries vary due to one being closer to the head and much hotter. I think I will need to get my head finned, or use the WA1111. Anyone have this problem?
 
Does anyone have any insight to offer? Am I murdering my Lithiums with heat? Someone else out there must be running a mag61. :help:
 
I should have been more descriptive. This happens when I go full bright for about 5 minutes continuous. Normally, I get pretty decent runtime- if I run it at 30 or 60 percent, or I use full bright in short bursts. The light gets freakin HOT. I saw Lux ran his full power for 25 minutes I think it was with no trouble. I dunno.
 
I don't think Mudman was using AW's V2 Mag C Incan Driver for his test according to his write up?
 
I read the mudmans chronicles of the mag 61. He had a fan blowing on it the whole time. This is not practical for me. I built this light to use every night at work. I need the light for distance and up close so I used the AW incan smartdriver. The problem is when I use the light in full bright for more than 5 minutes. The light gets hot, and it shuts off. I am thinking of sending the light to Jesus Hernandez to get it finned. The light is already banged up, so the finning would be strictly for heat dissipation. I am wondering if this is a waste of money and using a lower watt bulb is the answer. I just figured there must be some others out there who use the mag 61 for more than short burst show.
 
Hi there beetleguise, If one of your cells is measuring 3.1V after shut off, then I suspect that the cell shut down due to overdischarge protection kicking in. The cell voltage would not measure as low without load like that as it would under operation, so it quite probably got down to the 2.5V or so needed to shut off.

I tend to agree with EvilLithiumMan that one of your cells may be bad or they were not equally charged. As far as I know, AW did not incorporate an overheating protection circuit into the driver. If there was a problem with the driver electronics overheating, then waiting for it to cool down should allow the light to turn back on, unless of course the circuit is permanently damaged or one of the cells has overdischarge protection activated. If the light won't restart after cooling but will restart after recharging the cells, then there is a problem with one of the cells.

You really should consider using the WA01111 bulb too. It is still very bright and white and will give you longer runtimes with less heat.
 
1+ on 5761 2C generates heat, have not compaired finned head vs non-fin head run times. Current wisdom is finned helps cool and thus longer run times. Found what makes a difference regarding heat, measured by touch anyway, how I wish had access to a thermal imager, is ceramic insulation stuffed between head and reflector and around pedistal.

5761 runs cooler as does 64430's substitute tungsram 56580 at around 7.5A in 4C with stock head insulated as above. Posted somewhere else, am discoverying pedistal/switch properly modded, not using kiu socket and heat sink just bipin and insulation is capable of as others here have advocated will work with bulbs up to 10A and maybe more.

My ROP failures with li x2 battery solution, turning into instantflashing cash cows, quickly converted to bipins then flashed a bunch of 5761s, easy enough switching to 1111 thinking I over modded, decreased too much resistance. The fact is 5761 like any bulb has it's voltage limits and seems like gets a bad reputation. Give it 7.1v at the pins and it is a winner for me.

Jim
 
When the flashlight shuts off, I suspect it is the low voltage/overdischarge protection, but one battery is much more discharged than the other. The battery closest to the head is getting hotter and discharging faster than the other. I still have alot of electrons left in the other battery, but the flashlight discharges one faster on high(HOT) and shuts down way too early. I am thinking the 1111 is the way to go. My co-worker Aircraft800 runs one and only charges his light once a week! He uses his all night long too.
 
One thing I would like to add- I think AW's protected C cell lithium Ions are superb! My problem is definitely not the battery, or the incan smart driver. It has to be the heat.
 
Your theory that the cell closest to the head gets hotter and therefore cannot deliver as much power makes sense. If that is the case, then you should be able to repeat the phenomenon with the position of the cells reversed. So regardless of which cell is closer to the head it will always be the one to discharge sooner and trip the protection circuit. Please report back if you can test this out or already have.
 
I have been able to flip the batties and continue to use the light for a while ( after the low voltage cell recovered a little). I am not too worried since the low voltage protection will cut it out if it gets overdischarged. My light goes dim when BOTH batteried approach 3V and I shut it off.
For now, I will avoid 100% bright. There is a bulb out there that is about the same as the 5761, but only 20 watts, instead of the 30. I will try that one.
 
Does the same thing happen after you flip the cells? What are the voltages of the 2 cells after a discharge when you have changed them round? It would be a good idea to test this after a similar discharge time to see whether it is the heat or the cells themselves.
 
New discovery tonight! My light only seems to fail after I turn it off, and then try to turn it on after it has been running on 100%. I checked the voltages tonight, and they were at 3.7 each. I find that if I screw the tailcap off a few turns, screw it back on and try again, the light works. After reading a post by LuxLuther- "brightest mag mods" I found out that the 5761 runs dangerously close to the overcurrent protection of AW's protected Lithium C cells. My new guess is that when I select the light off, I am pushing the batteries just over the max current and they are actually tripping off. I am always able to turn my light on if I unscrew the tailcap and screw it back on. My light only fails after running it on high for an extended time or for a short time and then selecting it off (before selecting dim mode).I need to use a bulb that draws fewer amps, AND produces lower wattage.
 
Last edited:
The WA1111 has already been recommended here, but I'd add the WA1274. It would be running basically at spec on 2C li-ion. I run one in a similar setup and like it quite a lot - it's not dim and yellow, more like "normal" instead of insanely bright and white. You get more runtime, less heat and plenty of light, a pretty good combo.
 
OK, tonight I experienced my light not turning on again until I unscrewed the tailcap and put it back on again. This time I had fresh batteries and I was on dim. I don't understand it. I checked the amp draw on dim and it was way under 5 amps. Maybe it is my Incan smartdriver. I hope not. I still plan on using a lower watt bulb- around 20 rated, but my problem remains. If I figure anything out I will post it.
 
Mystery solved! It is NOT my batteries or smartdriver at all. I kept thinking about the fact that I had to unscrew the tailcap and tighten it to get it to work. Everything looked good. I know that the smartdriver needs to dig into the light past the anodizing to get a good ground, but that looked good. I got out my flukemeter and just started checking everything.:stupid: But, :twothumbs! The tailspring was cutdown to accomodate the protected cell extra length, but it had a good ground. What I did wrong was check the tailspring resistance at the tip of the cut, not where the actual contact was taking place. The tailspring had an intermittent high resistance. I had to buff off the plating, then I had much lower resistance all along the places where the spring contacted the battery. So far, no problems. I am charging my batteries right now, and I probably won't run the light until tomorrow night. If the problem returns, I will post again, otherwise case closed!
 
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