Did you know that some (relatively cheap 14.4V/3Ah) rechargeable batteries for power tools can power that professional 12V LED spot for 10 to 15 minutes at full power?

The Maintenance dept. in our company has dozens of them so this will save my next project without asking that 1500 EUR for a "Pro solution" (for 5 LED spots).
Even if you need to buy new batteries you pay +/- 75 EUR each.

Of course you need to make a backplate yourself.
The one in the picture will be painted black so nobody will notice the D.I.Y..

Also the external connection will become an internal one. So the XLR connector can still be used for adapters.

Are they really that cheap to be worth it? For inexpensive 12V li-ion batteries, I've been using ones I get on ebay. You can get 12V 9.8Ah li-ion batteries for $40 shipped free, thats almost three times the capacity of yours in a much simpler form factor. I just velcro them to the back of my monitors or lights and they have a built in standard 2.1mm dc barrel plug which is what most things take or that can be easily adapted to 4pin XLR with a $10 cable.

With those bigger batteries for longer runs or bigger lights/monitors and the smaller ones with level indicators for smaller ones, its hard to beat the price and simplicity... Just make sure you get the 12.6V 1A or 1.5A charger since the ones they come with are usually like 350ma or something which takes many hours to charge.

I also use them to power remote controlled RGB led light strips which can be a pretty powerful tool and happen to take 12V 2.1mm DC plug power as well. I made my halloween costume out of them this year :)

Brand New 12V 9800mAh DC Rechargeable Li ion Battery Adapter for CCTV Camera Cam | eBay (http://www.ebay.com/itm/370881418150)
4-Pin XLR Power Adapter | PROCAM Photo & Video Gear (http://procam.com/4-pin-xlr-power-adapter)
Portable DC 12V 3800mAh USB 5V 5600mAh Li ion Rechargeable Battery Power Pack | eBay (http://www.ebay.com/itm/121096367860)
Li ion Polymer LED Battery Pack Charger 8 4V 16 8 12 6 1A 1 5A 2S3S4S Cell Lot | eBay (http://www.ebay.com/itm/370911321448)