@flascgus Looks like you have the right voltage. Nimh or Nicad are 1.2v/cell and you have 7 there, making 8.4v. The only thing I can think of is if it was reversed polarity. Did you check it with a meter?

I've built these before and always use the Castle Creations 20a bec. Had one plugged into the wall (via wall wart 12 v AC-DC converter) for 3-4 weeks straight doing timelapse shots. They also work well from any battery with a voltage above the target voltage. You do have to have a little usb device to set the voltage though. (castle link software for PC only)

Caution should be taken with Lipos. They have been known to burn houses down. If you accidentally puncture it, it will pretty much become a fireball. Same thing if you charge it the wrong way. You need a balance charger. Care also needs to be taken to not discharge them below 80% of their mAh capacity, or about 3.8v per cell or they will have a very short life.
For this application it would be good to get ones that come in a hard case, meant for RC cars.

@flaschus Huh yeah I guess voltage spikes like @feha said. I dunno. Again I am the farthest thing from an electrician. I just have wired up some RC stuff in the past. Did the camera die right on a fresh battery? Because the lipos usually have higher voltage when just charged then settle down after a little bit.

@flaschus do not connect anything to GH1/GH2 without a voltage stabilizer ... think of if lipo or whatever battery is fault or get a problem they can release uncontrolled power etc ... The DC coupler have not any protection, just passes the current straight to the camera ... I will be making soon a video tutorial about this ...

@tommyp

here is a pic of the setup that killed the gh1... thoughts?

The red is the power black is the ground hook them to the same color on your UBEC input and you are good to go. Oh I forgot you will need some sort of connector to fit to the battery plug. Then you would wire that to the input of the ubec.

I would take a voltage reading with a multimeter to see what voltage the ubec is putting out just to be totally safe.

@ flaschus I don't know the voltage spec for teh GH1 but its prob different to the GH2. Funny really if panasoic see this post they are going to try and make camera that wont work with any battery but their own.

Panasonic should make a better battery then we would have to go though all this.

@flaschus what was your setup?

I am the farthest thing from an electrician but I would just tap them both off of the 14.8 line don't stack them. My quad just goes from battery to a power spider. Just a bunch of wires soldered all together at one point. My Ubec's and ESCs are all drawing from that one point which is powered from one line from the battery. The ground is the same way.

I just ordered a 9v ubec from hobbypartz. Going to run the gh2 off of my RC lipos. Have been wanting to do this for a while but never took the time to buy the UBEC. I have been running my gh2 off of an old sony camcorder brick connected to the battery adapter if I needed long recording times. But that is usually for performances where I can get power. It would be convenient for some jobs coming up that I have batteries so I guess now is the time to figure out a better power solution. I would like to have something more professional like the Dolgin but it is just too much money (and I would like it to lock the battery in place) when I have all but $11 of the materials siting in front of me. I was thinking about buying a vagabond mini and just trying to use that battery but I am not sure what connector that is and it costs a bit more than $11. I would use a vagabond way more than the Dolgin so it would be worthwhile.

@chainsawfilms - Rc batteries have balancing plugs that you can draw down certain cells of the battery to get different voltage. Lipos are 3.7v a cell though. So you could get 3.7, 7.4, 11.1 or 14.8 off of a lipo battery if you drew down certain cells independently of the main power out. I don't think it is a good idea for large draws though since the balance leads are usually tiny. But I have used them for powering LED strip lights on a quadcopter. I am not sure about NiMh I think they are 1.7v or something a cell. I have only used lipos so I am not sure of the feasibility of tapping a NiMh or if you even can.

@ChainsawFilms - http://www.personal-view.com/talks/discussion/comment/51421#Comment_51421

Thats the topic that talks about using a rig setup with custom battery. I don't if its what ya looking for.

@ChainsawFilms, it is possible and some are doing it from other posts topics. In fact one guy made his own with different outputs for each device. It would be quite difficult to split the voltage, so that it each device gets its own correct voltage. However the RC battery packs are a good alternative to most battery solutions because of their high resistance to discharge.

@benfx i like the design of this battery, but the mah capacity is to low .. if you check the voltage for higher voltage you get less mah ...