A while back I posted about some available 12V DC batteries you can use from Ryobi. They've been working great and many people have adapted them on Timelapse rigs and motion controlled sliders. Here's another option. Now I'm fairly weary about posting no name battery packs, so i've been testing these for a few weeks now before I decide if they are any good.
I originally purchased two of these CCTV Battery packs because of the 5V USB option. These little batteries hold quite a charge and i'm able to fully bring my dead cell phone or iPad back to life (charging through USB) several times over before needing to recharge the Pack again. These USB chargers are the most handy thing when you can't be tied to an outlet (like when traveling).
They also come with a double sided barrel connector to power up 12V DC items, and those have been coming in quite handy as well. The connector fits most standard Camera accessories, but you can always get additional ones to power up other accessories that will run on 12V or 5V DC. [Note] At Radio Shack it's 'AdaptaPlug Size N', elsewhere the common plug is 5.5mm OD and 2.5mm ID Male Plug. The battery uses negative from the outside and sends positive from the inside. Just make sure you have the inside as Positive and the Outside as Negative when making your DIY plug. You can see what that looks like, and find some easy DIY tips here: 5.5mm Male DC Plug Tips
I've been able to power up the Z96 LED light, the 312 LED Video lights, the SmallHD DP6 LCD monitor (and other monitors), the 352 LED Ring Light, and the list goes on and on. So many times you'll catch one of your accessories out of AA's or Sony's, and this backup battery solves them all. [Update] The Zoom H1 can be powered via USB, just figured that out when my AA battery was dying out on location.
I haven't done any real battery testing to see if the 3800mah /12V DC specs they list on the website is actual, but they do hold a charge and power up all my accessories for quite some time. Fairly light weight so all it takes is a bit of Velcro to hang it on the back of your Lilliput LCD monitors, or Portable LED lights that can accept DC in (like the Z96 or 312 LEDs). Unfortunately my 900 LED lights require 14V DC to be at it's 'Brightest' setting, but these little 12V DC batteries will power them up as well. Definitely not a bad price, and I have a few more on order. Trust me, i'm still putting them through the ringer. You can find them (click here).
[Update] Some of these items might not ship with the correct barrel adapter which is 5.5mm OD and 2.5mm ID. A comment left by Luca has links to some adapter cables. [Thanks Luca]
I found these DC cables that should fit quite nicely. The problem is, they're quite short:
So here is an extension cable: