More power to you!
(Supersizing a scope-side portable power source)
As a completely sealed unit, these Gel-Cells have little likelyhood of leaking or causing damage, and I'm told they are even allowed to be shipped via air-freight. The battery box provides a convenient way of mounting all the harware though, as well as supplying a strap to carry it.

I decided to incorporate four individual 12V power outlets, so as to reduce the tangle of cables or octopus-style adapters. I also wanted to protect these via circuit breakers, but could not get the appropriate panel mounted CBs on short notice, so used panel-mounted fuses instead.
With ever increasing demands for scope-side power capacity, and not being overly fond of being tethered to an AC power line, meeting those needs was becoming quite a challenge. I had "graduated" from a single 17AH 12VDC 
12VDC 17AH Portable "Jump-Start" Gel-Cell Batteries
65AH Battery and a completed unit  
JumpStart, only to find that even two were becoming taxed with my longer sessions. Granted they were getting quite a workout, often starting their service-day not much beyond afternoon, providing power to a 5" LCD and an AP 900 or 600GTO mount tracking the sun.

When night arrived, they picked up the added burden of several dew-heaters and and an SBIG STV auto-guider, gallantly giving their best but often not enough! I would find myself juggling devices and cords to keep the mounts driven or auto-guider guiding, and needed desperately to find a solution.I had considered going to a 34AH battery, but even that would only measure up to my current capacity, and the two smaller units would still be required as supplements.
I then had the extremely good fortune of being tasked to perform a systems upgrade to several large-scale memory arrays with (drum roll please!) ... a total of ten 12VDC 65AH Gel-Cells that were to be disposed of!

Of that number, although five had difficulty in maintaining a charge, the remaining five were in pristine condition. The wheels started to spin as I thought of how to best contain, transport, and utilize these 48 pound beasts. Fortune was again on my side, as being a standard size battery  (group 24), the local marine supply store had a case that fit like a glove and could become the basis for a portable power source.
Front view showing the fuses and
master switch
Side view of power-out ports
The case allows convenient mounting of the power-out ports on each end, with a total of four being installed, each bank having its own fused protection.

The outlet ports are Radio Shack units which have neat rubber caps and come equipped with in-line fuses, which were canabalized in lieu of the panel mount type.

Radio Shack 12VDC Adapter Outlet PN # 270-1556
Rear-view showing the charging port
The original configuration for charging and accessing these cells was via a multi-conductor umbilical that feeds directly to the Gel-Cell electrodes. This was retained in an effort to ease the charging process, and was routed to the rear of the unit.  

Normally nestled just inside the top cover wings, it is extended here to denote its location. A mating umbilical (not shown) connects to the charger.

It perhaps would be almost as easy to simply remove the cover, but what the hey... I already had the harness!
Top of the unit and power monitor
Here you can see the four power-out ports (two each on either end), their associated fuses in the recessed coves, the master switch (in the lower right corner), and the voltage monitor.

The master switch applies power to the fuses, which in turn provide power to the left and right power-port banks.

Having had much angst with people striking panel-mounted fuses, I  was quite  happy to find these protective nooks in which to place them.
I wanted something to indicate when the unit was on, and also to be able to monitor the voltage level.

While toying with the idea of throwing together a perf-board mounted LED monitoring circuit, I discovered Radio Shack had an "Vehicle Battery Tester" (PN# 22-112) that would fit the bill for six bucks (good fortune strikes yet again!)

With such a small current draw, I opted to keep things simple by wiring it to the switch leg of the master, rather than use a separate momentary switch. When the power unit is switched on the monitor also comes on.
Close-up of the power monitor
And the guts....
Nothing elaborate here, as  this "under-cover" shot shows the simple arrangement used to route power from the battery to the receptacles, via the master switch and fuses.

The only surpise that befell me was that I couldn't find anyone who wanted these Gel-Cells!!! Eventually, they all found homes, but I was amazed that no one wanted these free (as in no $$$) cells!?!

Go figure!!!

UPDATE: It worked out so well, that I  just threw together a second one.