KPR118 Bulb Question

I have a few of the KPR118 bulbs I want to use in a 3D Mag.

Bulb is rated 7.2V @ 700ma (5watt ?) and is listed for a 6 C or D cells.
6 cells is 9V but want to use 2 LiOn's in a 3D mag.
Does the 9V (6D alkaline cells) have that much sag at .7amp draw
to where the 2 LiOn cells will be OK with the KPR118

It should be OK at 8.4V (2 LiOn), am I correct????

I will be sleeving the tube (3D Mag) for the LiOn's and using a dummy cell extender to
make up the difference in cell length.

I just want to get a little more brightness out of my 3D Mag without
resorting to a ROP or LED conversion.

Suggestions or comments??

Thanks

You might want to check out some of the threads regarding using the 6 cell Magnum Star bulb with 2 Li-ion cells. That seems pretty close to what you are attempting.

Lightfoot98 said:

[..]Bulb is rated 7.2V @ 700ma (5watt ?) and is listed for a 6 C or D cells.[...]Does the 9V (6D alkaline cells) have that much sag at .7amp draw[...]

Click to expand...

It is not uncommon for bulbs (500ma and above) for C and D cells to be rated at 1.2V per cell. This goes all the way back to carbon-zinc batteries when 2.4V 500ma bulbs were everywhere. New cells don't sag that much but the sag increases as the cells are depleted.

Your success will largely be determined by the durability of the filament in your particular bulbs. The same filament can be rated at different voltages and wattages, just different lifespan (hours). There are some good threads on that also.

You might want to just consider your first attempt "sacrificial". Good luck!

Mag's WhiteStar Kryton 6 cell bulb is 820mA @ 7.2v
Mag's MagnumStar Xenon 6 cell is 840mA @ 7.2v
-both of these bulbs will outperform the KPR118

*MagnumStar 5 cell will pull 945mA at 7.2v, but requires that you let batteries rest for 2 hours after charging to avoid blowing the bulb
*Philips HPX-53 5 cell Xenon bulb will pull 1060mA at 7.2v, doesn't require any resting period, and will be brighter but not quite as white as the MagStar 5 cell