5761 Questions

[max52]

I bought several 5761s to play with. I first tried one in an AW 2c M*G. The 5761 pulled way too much out of the AW C cells. I now have a 5761 in a M*G 2 D with a Kiu High temp running 8 Rayovac Hybrid's. The output is incredible. My question is: How is 5761 able to handle 9.6v? Is the 5761 causing so much "sag" in the 8 cells that only 7.2v is being delivered? I have used this configuration over a period of time with no problems.

Should I shoot for 7.2V in future configurations?

 

[mdocod]

My guess is that the rayovac hybrids fall on their face at 5 amps

 

[lebox97]

there are several threads about this lamp...
IIRC - 7.2v is MAX - anything over and you get

 

[matrixshaman]

You scared me - I thought okay here's another newbie with 20 questions only he's gone totally overboard with 5761 questions

 

[max52]

I think I need to change configuration. I use the Titanium "Power Max" 1800s in my 12 cell modified to run 50W Mr16 lamps. The Titanium 1800s hold up well. I was also thinking about the FiveMega 6 x 14500 holder using AW 14500s. I wonder whether the AW 14500s ca take the amps? Any Thoughts?

 

[LuxLuthor]

No, generally the AW Li-Ions are set to break the connection with their PTC at 5A (+/- 0.5) to protect the cells. In addition, the 14500 is pretty much the weakling of those cells. While you can get the voltage with Li-Ions, you cannot get the greater than 5.5A that the 5761 bulb needs to shine.

That is why the 1800's or even better, the CBP Elite 1700 AA's which can crank out 25A and still sustain their voltage.

 

[lebox97]

the best person to help you with these AW questions is "AW",
always helpful and all around awesome :twothumbs guy -
oh, and he does hotwires setups himself

PM him

 

[jimjones3630]

Many of us who have M@g61 runing the 5761 used AW new C cell when it came out. Lights that worked with one click started to require 2 or more clicks to work and some folks previously working 5761 would not work at all.

What you might want to do is measure the voltage at the bulb when on.
Stick DMM probes to both pins, or loop with wire to make the connection and see what volts at the bulb.

Lately I have had a "weak" lot of 5761 and flashing around 7.1vbulb or so.

Jim

 

[max52]

I switched configuration to 2 D Lions. They can handle the amp draw, and I don't have mess around with with Charging 6 cells. Performs great.

 

[JimmyM]

The 5761 can take 2 D Li-Ions with no regulator?

 

[max52]

Incredible output. I really like the 5761. No "insta-flash".
I was concerned, because I normally charge the D Lions to 4.1X V. This time I charged them to 4.25V. I crossed my fingers and hit the switch expecting a insta-flash but instead got the great output of the 5761.

Voltage measured at 6.92V at the lamp.

 

[Raoul_Duke]

What king of D li-ions are you using.
I have read on here not to charge D li-ions over 4.1, 4.25V is definatley too high I'm hopeing your D's are protected.

 

[max52]

The D Lions are protected, and I am very careful when charging them. They probably have the potential to go off like a hand grenade if mis-handled. Like I said, I balance them carefully, and monitor the charging process costantly. I screwed up and over-charged 1, then to balance had to charge the other one to 4.25. I know this is the high end of charging. I like them at 4.15V.

 

[jimjones3630]

6.92vbulb is great with 2D's no wonder has incredible output.

Vbulb and Vbat. for me tells the whole story of a mod. When I wasn't taking these measurements, had a couple of m@g61 built sort of blindly-like the analogy- doing differnet resistance fixs untill both started instan-flashing. I didn't have an idea why.

Rsistance is your friend not just with this bulb but all bulbs will instan-flash at some point. The reason could run 5761 on 8 cells when 7 historically is the max is they were saging down below the instan-flash point of the 5761. If use 8 upgraded cells known for high amp ability probable start instan-flashing. Same reason with your D cells. Measuring bat voltage static is not as useful as measuring them in the mod to obtain vbat.

Incredible output. I really like the 5761. No "insta-flash".
I was concerned, because I normally charge the D Lions to 4.1X V. This time I charged them to 4.25V. I crossed my fingers and hit the switch expecting a insta-flash but instead got the great output of the 5761.

Voltage measured at 6.92V at the lamp.

 

[JimmyM]

I'm running the 64275 on 2 of Kai's D Li-Ions. I have AWR's Hotdriver set to 6.9V. The Vbat on 2 fresh off the charger cells is 7.5V when running. I want to tweak the '275 up to 7.0. It flashes on 7.2-7.25. I like the more robust 5761. But the filament of the 275 is so nice and small, it makes for a pretty decent hot spot even with the 2" FM reflector. I have a 2" Deep FM reflector/bezel that I'm using on an ROP-low. Maybe it would be best used on the 275 or 5761. Now that thing would THROW.

 

[BSBG]

I have a 2" Deep FM reflector/bezel that I'm using on an ROP-low. Maybe it would be best used on the 275 or 5761. Now that thing would THROW.

I'm not sure the 5761 will fit into the 2" deep unless you bore it out - the ROP is pretty tight and the 5761 is larger in diameter. But you are right, it would throw...

 

[LuxLuthor]

I'm not sure the 5761 will fit into the 2" deep unless you bore it out - the ROP is pretty tight and the 5761 is larger in diameter. But you are right, it would throw...

You are correct. The 5761 is 0.375" and the 2" Deep FM reflector bore is 0.34" and I don't know if it is worth taking a chance on the pristine 2" Deep SMO surface to bore it out.

 

[jimjones3630]

Just tried 2" deep reflector with 5761, did have to open it up not sure exactly what measurement is the opening. In the past, have opened up just enough then twist off pins for a $6 moment.

Didn't like the pencil beam effect. So, opened enough for 100w 62138 with 3xemolis in a 4C. Like the form of it and the beam. Usable side spill and throoos.