Coleman Twin LED Lantern; Battery and LED Swap...?

[LEDAdd1ct]

Rather than hijack existing threads, I thought I would start a new one. I have a basic idea of what I would like to do to the Coleman Twin LED Lantern as seen here:

http://www.coleman.com/coleman/colemancom/detail.asp?product_id=2000001147&categoryid=1045

If both these mods cannot be done, I do not think I will purchase this lantern.

Mod One:

I would like to replace the stock Cree LEDs with Cree P4 7Cs.

a) Has anyone accessed the internals of this particular lantern?

b) If not, do any current owners see an easy path to the LEDs? Is the head screwed on? Glued on? Attached by screws?


Mod Two:

SLA batteries and chargers are cheap, and certainly more manageable than eight LSD "D" Ni-Mh cells. Is the battery cavity in the Coleman Twin LED Lantern large enough to accomodate a 12volt SLA battery of the same capacity as the equivalent "D" size Ni-Mh cell, i.e. 10-12aH?

I think with these two mods, this lantern would be simply beautiful.

EDITS:

4/22/09 7:17 P.M.

adirondackdestroyer has established that the top is attached by screws, and that in all likelihood, removing those screws will provide access to the LEDs.

4/28/09 2:48 P.M.

adirondackdestroyer has established the internal cavity is approximately five inches long, circular, and has a square peg which the battery holder slides around. The cells are held in a circular array.

 

[LEDAdd1ct]

After I received the specs provided by adirondackdestroyer (see Post #1), I decided that due to the weight and dimensions, an SLA battery would not be the best fit. After doing some research, I decided I could either use the Accupower LSD D cells, or, find some other type of battery pack. My goal is for the pack to be able to be charged inside the light. I found this pack and charger combination here:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=5124

"Customize LiFePO4 Battery & charger: 12.8V 9.6Ah (123Wh, 21A rate ) with separate charge and discharge terminal & 3A charger"

I believe that the pack, rated at 4.5" x 3.3" x 3.3" will fit inside the battery compartment if the center peg is filed down. On the product page, it specs the pack at 14.6 volts peak with a working voltage of 12.8 volts. Though it is more expensive than the Accupower cells, the time it takes to charge this pack, about five hours, plus the convenience of not having eight cells to handle, plus the fact I can drill a small hole in the side to install a charging jack, which, with the separate charging and discharging wires and the accompanying reduction in weight make it worth it. Additionally, LiFePO4 is advertised as a very safe chemistry without the risks of traditional li-ion cells (please correct me if I am in error on this).

Does anyone know what the maximum voltage the buck circuit in the lantern can handle? 1.5volts x 8 "D" cells = 12 volts. The working voltage of the pack is 12.8 volts, but off the charger, it could be as high as 14.6 volts. Obviously, I do not wish to use 14.6 volts if the buck circuit cannot handle it. I called Coleman, and after waiting on hold for fifteen minutes, I politely asked the representative for the maximum voltage the buck circuit can handle. He adamantly and severely refused to attempt to answer the question, stating that if "you wanted to make a rocketship out of it, with today's technology, you probably could!" He spurned me, declining to forward my question to engineering or anyone in the technical/R&D department.

So, does anyone have any thoughts on this? Does anyone have any past experience working with the guts of this lantern who can identify what the maximum working voltage of this lantern is/might be? I am fairly certain that the "working voltage" of 12.8 volts would be just fine, but I am hesitant to put 14.6 volts in...