Philips 5761, which host?

[uknewbie]

Hi all,

I have on their way to me an FM bi-pin socket adapter and a Philips 5761.

Can I run this with 6AA Eneloops in a2D direct drive without ?

Otherwise what would be the best host/battery combo for this bulb. Runtime doesn't matter, would rather avoid having to use a soft start or Lithium unless 18650.

Small as possible of course :thumbsup: 2C with 2 x 18650 perhaps??

Thanks,
Craig.

 

[mrartillery]

For a 2 D with 6nimh's you dont need a soft start, but you will need to let the cells rest after charging as you'll have almost 8.5v, or youll need a bleeding lamp, here; http://www.candlepowerforums.com/vb/showthread.php?t=246836

This is the same setup i run, dont expect much over 20min of runtime though, as the 5761 draws over 5 amps.

As for the 2 c, you can run lithiums such as a IMR26500 in a bored host which you can do yourself with a brake cylinder hone or similiar, BUT you will need a soft start or a NTC in the tailcap to take care of over voltage.

NTC's are a cheap and relatively easy fix, described here; http://www.candlepowerforums.com/vb/showthread.php?t=170972

and here; http://www.candlepowerforums.com/vb/showthread.php?t=185335

 

[uknewbie]

Thanks.

What is the safe resting period for 6 x AA Eneloops before running this setup?

Could I just take voltage reading from the cells to make sure they had rested enough?

Thanks,
Craig.

 

[mrartillery]

Never messed with eneloops, but i do know they hold there charge well, ive read some have had blown bulbs 24 hours after charging, so like I said you may want to buy you a MR16 (50w) to bleed the excess voltage off with.

And yes, you may want to invest in a good DMM, or digital multimeter to read the voltage. A good rule of thumb is dont put much more than 7.8v on a 5761, you'll blow them really quick, and most problems with blown 61's is at start up. This is why people use NTC's and soft starts so that the voltage gradually hits the bulb not all at once.

But if you let it rest and make sure the voltage is within range you should be fine, i haven't blown one yet.

Here's you a graph to show applied voltage, lumen output and bulb life expectancy http://i61.photobucket.com/albums/h75/pike444/bulbs/5761.jpg

 

[Databyter]

For that setup with 6 aa's your basically looking at 7.2 V nominal after rest or under load, but up to 9V after a full charge. (This assuming 1.2 V per cell nominal, and up to 1.5 hot off the charger).

For a 6 Volt bulb that is best over-driven at about 7.2 V (1400 lumens vs. about 750 for the stock 6V manufacturer recommended Voltage) you only have about a half of a volt before it gets to a probable insta-flash. I like to think of flashing a bulb as just a really high performance incident with a remarkably short run time. I think most are not interested in this particular bulb putting out about 4000 lumens for 300 milliseconds.

Chart pic. Compliments of Lux Luthor's Destructive Bulb Testing here

http://www.candlepowerforums.com/vb/showthread.php?t=179748

You really have to be careful which means, ideally a soft start switch which defaults to low when un-powered (like AW's does I believe). Then you can use it fresh off the charger at a lower setting, and then crank it up under load after a while as needed. Alternatly you will have to do what MrArtillary says for direct drive and rest and test your pack, or use 5 cells instead of 6. I would think that lithium cells would only make your voltage situation even more volitale and less flexible for this voltage sensitive application. It's a nice bulb, but it is very voltage sensitive for over driving.

If you look at some of the other bulb charts in Lux Luthors Destructive Bulb Testing thread you will see some other 6V based bulbs that can be overdriven a bit more before flashing which might help a bit, Notably the ROP 6V and the Osram 64430, there is another bulb that looks good too but I think it's kind of hard to get, and probably more expensive when you find a supplier (the GE bulb). Also some of the bulbs won't fit in the bi pin adapter, some will.


SIDE NOTE: I just got one of these AW switches, and although I'm still training my fingers to do the right things ( I unconsciously try to turn it off with a single click and it just changes levels) I LOVE it for my M*g85. I usually use the 60% level and sometimes the 30% for moderate needs but it's nice to have the full throw/brightness capability. It about triples the amount of time before I need to charge it.

I just bought another one for a M*G 623 build I am doing. I don't want to start fires, I want a light that I can use on lower levels that has a shock and awe capability built in. I am going to do alot of reflector experimentation to see if I can overcome the ugly artifacts that this bulb has.

P.S. Lux if your seeing this, I am not rushing you but I just feel bad for your poor neglected Capacitive discharge spot welder, they require alot of love and attention.

 

[uknewbie]

Wow thanks for the great replies.

If my very rough calculations are correct, you are looking at easily over $200 build cost for a 2D 6AA 5761 with an AW switch?

Doesn't really seem like bang for buck when you consider what you could buy built for that money, does it?

 

[Databyter]

Wow thanks for the great replies.

If my very rough calculations are correct, you are looking at easily over $200 build cost for a 2D 6AA 5761 with an AW switch?

Doesn't really seem like bang for buck when you consider what you could buy built for that money, does it?

Clear your mind and walk towards the light.

 

[Steve in SoCal]

Wow thanks for the great replies.

If my very rough calculations are correct, you are looking at easily over $200 build cost for a 2D 6AA 5761 with an AW switch?

Doesn't really seem like bang for buck when you consider what you could buy built for that money, does it?

A ROP_LE build is cheaper and should put out approx. 1000 bulb lumens. I used an old 2D host, the Pelican 3854 High bulb, added a metal reflector, a new lens and 2xAW IMR18650s. After a little monkeying around with the spring and a PVC tube to sleeve the batteries you are done.

 

[uknewbie]

I already have a ROP high in a 6D on 6 x 10Ah LSD D cells. Pretty bright.

Was going to run the 5761 in it but apparently it would as those cells won't sag enough to save that bulb.

Could always just bleed those to get the voltage down and check it is 1.2 per cell before running it?

 

[mrartillery]

I love my ROP high (3854), ive got it a 2 C with 2 IMR26500's, prob my favorite all around light, due to the size and the beam is just beautiful, basically the same output as the 5761 as well, also can handle more voltage. The 5761 is a little whiter though.

 

[uknewbie]

The destruction charts show the 5761 as something like double the Lux at the same 7.2v as the 3854.

I appreciate this will not appear twice as bright, but still brighter, and like you say, whiter, which is why I was looking to use it instead.

How long would my D cells need to rest, or be bled using another bulb before I could safely run the 5761 do you know?

Many thanks.

 

[mrartillery]

The destruction charts show the 5761 as something like double the Lux at the same 7.2v as the 3854.

I appreciate this will not appear twice as bright, but still brighter, and like you say, whiter, which is why I was looking to use it instead.

How long would my D cells need to rest, or be bled using another bulb before I could safely run the 5761 do you know?

Many thanks.

Honestly, I'd be afraid to make a guess being that ive never messed with these cells before, since you say youre using a drop in bi-pin socket you could use the 3854-L to bleed voltage off, its very resilient to overdrive, just run it for a minute or two checking your voltage periodically at the switch until its within range to use the 5761.