Will a ROP/5761 be brighter on 2xC LiIon or 6AA?

[GarageBoy]

I'm guessing the runtime is down compared to 6AA, but will it be as bright? Thanks (can't seem to get the search function to take ROP)

 

[iapyx]

I'm guessing the runtime is down compared to 6AA, but will it be as bright? Thanks (can't seem to get the search function to take ROP)

Ask NL (Northern Lights) as he knows everyting about the 5761 and batteries. I'd say yes.

edit: 6x1.2V = 7.2V (nimh) versus 2x3.7V = 7.4 V (li-ion)
conclusion: the 2C setup should be brighter.

And I think the runtime of the 2C is longer too

 

[IMSabbel]

You are taking a short-cut there.

It all depends on the cells themselfs. In this case, on how big the voltage drop under load is.
Seeing that C-lithiums arent the most optimized size, i think its prettly likely that eneloops might fare better.

 

[copperfox]

My ROP is brighter on 2xC li-ion than it was on 6 Eneloops. I didn't test runtime differences

Seeing that C-lithiums arent the most optimized size, i think its prettly likely that eneloops might fare better.

What do you mean, not the most optimized size?

 

[iapyx]

My ROP is brighter on 2xC li-ion than it was on 6 Eneloops. I didn't test runtime differences



What do you mean, not the most optimized size?

I think he means that you need an extender in order to have the C-cells fit in a C mag. In a MagD they fit without any problem.

I was referring to AW C-cells.

 

[KiwiMark]

I'm guessing the runtime is down compared to 6AA, but will it be as bright? Thanks (can't seem to get the search function to take ROP)

The Li-ion option should be brighter. But it would be risky to run the 5761 from 2 x Li-ion cells. Lux Luthor's destructive bulb testing shows that the 5761 will at 7.9V. If you get the new IMR 26500 cells from AW you will find that they are capable of delivering over 8V when fresh.

For a ROP High it should be OK, but it will vary bulb to bulb, I instaflashed a ROP High bulb from 2 Li-ion D cells. I don't know how long the bulb would last even if it doesn't instaflash.

For a ROP Low it should be fine - I haven't blown one yet running from 2 Li-ion D cells.

I am thinking of trying 5 x IMR 26500 cells to run a 64458 bulb - should be bright!
http://i61.photobucket.com/albums/h75/pike444/bulbs/64458.jpg
5 cells should be around 18.5 volts and 9.9 amps for 183 watts of power and 5900 Lumen.

 

[davidt]

Here is my experience.

With a pack of nimh elite 1700s wired directly to the switch with fresh voltage of 8.55 volts my rop high bulb pulls 4.40 amps. And using luxluthor's destructive incan bulb testing chart it indicated the pack is outputing 7.2 volts.

With kaidomain's D lithium stick and fresh voltage of 8.53 volts my rop bulb pulls 4.30 amps. Using luxluthor's destructive incan bulb testing chart it indicates the pack is outputing 7.0 volts.

I believe using a rop high bulb a nimh pack would be slightly brighter.

 

[KiwiMark]

Here is my experience.

With a pack of nimh elite 1700s wired directly to the switch with fresh voltage of 8.55 volts my rop high bulb pulls 4.40 amps. And using luxluthor's destructive incan bulb testing chart it indicated the pack is outputing 7.2 volts.

With kaidomain's D lithium stick and fresh voltage of 8.53 volts my rop bulb pulls 4.30 amps. Using luxluthor's destructive incan bulb testing chart it indicates the pack is outputing 7.0 volts.

I believe using a rop high bulb a nimh pack would be slightly brighter.

I suspect you had a dodgy Li-ion cell - 7.0 volts is WAY too low, especially for D cells. If not a dodgy cell then a dodgy protective circuit with too much resistance.

I am also VERY sure you wouldn't get that with AW's IMR cells - the IMR cells are capable of delivering a LOT more than 4.4 amps with a very low voltage sag. They would probably be able to give 8.0 volts when fresh off the charger, droping to 7.6 within a minute or 2. Also AW cells are good quality and much less likely to have a dodgy cell. On top of that they IMR cells don't have any protective circuit to add resistance.