Pelican Big D bulb in ROP, how much voltage can it take?

exodus125

Enlightened
Joined
Oct 29, 2008
Messages
333
Location
Miami, FL
I use to have an ROP using the big d bulb. The adapter I was using was from kaidomain and it had a lot of resistance. Now I have a very good adapter and I am wondering if I put 6 AA eneloops at 1.5 or 1.6 V each that's about 9V. Can the Big D bulb take that much voltage? Would I need to let the batteries sit before I run the ROP?

In the incan bulb destruction test, the high bulb flashed at 8.6 v and the low flashed at 9.7 v.
 
Last edited:

J3004

Newly Enlightened
Joined
May 24, 2008
Messages
90
Location
Germany
Eneloops don't have 1.5-1.6V.

They have normally 1.2-1.3V each.

6 of them is no problem for the bulb.
 

exodus125

Enlightened
Joined
Oct 29, 2008
Messages
333
Location
Miami, FL
Eneloops don't have 1.5-1.6V.

They have normally 1.2-1.3V each.

6 of them is no problem for the bulb.

why is it that when I put the batteries in the sanyo charger and I check them after fully charging it tells me the batteries are at 1.47?
 

Benson

Flashlight Enthusiast
Joined
Feb 15, 2009
Messages
1,145
why is it that when I put the batteries in the sanyo charger and I check them after fully charging it tells me the batteries are at 1.47?
Because they are fully charged (not on the plateau where they deliver most of their energy), and you're measuring voltage with no load.
Silverfox's NiMH shootout shows graphs of batteries under various loads; you can see how the voltage at low currents is substantially above even the starting voltage under moderate loads. (Eneloops are a little over half-way down the page.)
 

YCbCr

Newly Enlightened
Joined
Nov 15, 2009
Messages
1
Hi there!

I was thinking on a big & heavy ROP mod, using a 4D Mag, in which the 3854H bulb seems to be unnnderdriven with 4 alkaline D cells.
What do you think, could it take 6 of them? (Judging by the 6 Eneloops mentioned many times; but their voltage is also lower.)
I ask this because I plan to use an extension, but don't know whether I should get a 1 or 2 cell; buying both would be over the budget. :(
Anyway, the 2D could be used with a dummy cell too as a cheap and universal solution. :)

Or on a second thought: may the 3853H with 6 batteries be a viable option to better match the voltages?
I do have a vast supply of D cells, hence not thinking with 18650s or AAs (but portals :D, it won't be used so much to consider rechargeables (yet?)).
 

VegasF6

Flashlight Enthusiast
Joined
Dec 5, 2007
Messages
1,449
Location
Las Vegas
Just for the sake of testing it, you could simply complete the circuit with 6 batteries and a piece of wire, alligator clip, etc. For C cells you can use a piece of PVC pipe (1" I think) or for D cells, tape, a piece of paper, rare earth magnets etc. That will save you the money of buying an extension you may not want.
 
Top