I'm currently searching for a cheap and high capacity power source to power my slider and the mx2.

I had a look on a few threads and a lot of people seem to suggest the blue li-ion battery packs like this one:
http://www.ebay.com/itm/12V-DC-9800mA-R ... 4ac2f68505

How much capacity is useful?

And in the shop of kids of all ages I found this pack (amazon link for english description)
http://www.amazon.com/Poweradd-Pilot-Pr ... ds=xtpower

with 2300mAh - not exactly the one linked above.
and the exact model (in german)
http://shop.kids-of-all-ages.de/motion- ... k-23000mah



I do like this one more because it seems more versatile, for charging the phone for example.
the 2300mAh version costs around 100 euro.
There is also a solar model for 10 bucks more, is it useful to spend a bit more for this?

Thanks for your help

I'd go for about a 6000mAH 12v battery myself.
Personally I like to just get 10,000mAH 12v batteries, as they are also good for powering a DSLR for a full 24hours.

Built in solar is generally not worth it, as it takes about 3 to 4 days of good sunlight to charge it with such a small solar panel.

Also beware!
23000mAH at 5v is not the same as 23000mAH at 12v. If a battery has built in USB power they are probably quoting the 5v rate, which means it only has about 40% of the capacity of the same number on a 12v battery.

I just picked up one of these for a similar rig. Really like it so far, may buy another just to have...
http://www.amazon.com/gp/aw/d/B00935L44 ... +power+12v

Nothing comes close the these batteries http://www.amazon.com/gp/product/B0056B ... EI3EMXUPTH

They are the same ones found in the Kessler Ion. You could save yourself lots of head ache and save up for the kessler ion and not have to build out your own weather proofing and battery charge meter + connections. I don't recommend any other battery. If you get any other battery, you will loose shots, you will be frustrated, you will end up spending more money then the ion costs eventually, by having to replace other batteries.

So do yourself a big favor and save up for the ion or build out a battery from the one linked on amazon! The ion Makes for a great tripod anker as well.

Cheers!