Before you connect any battery, please watch this video:

Definitely not. I always RTFM when $1000 gear at stake :)

but it does allow me to run span tests all day using only one battery charge cycle per day - i just use a cheapo tripod that has a small plate and allows me to get to the battery door and swap the battery in when I update the firmware, then back to the AC adapter to shoot for 2 hours or however long it takes for the GH2 to stop recording while I go do other stuff.

Sweet! All's well that ends well i guess.

And I wanted to put in that I've been using the dynex charger/AC adapter a lot without incident for the last 5 days or so while testing spanning with the hack. Works great, and useful for other random stuff too - like USB power and phone charging.

It should be ok regardless, just make sure that you test the polarity on the dc coupler contacts at the battery shaped end that goes into the camera. As long at it matches the polarity of the OEM battery you should be fine.

Ok, that makes sense.

Just make sure the one you order has the right tip included.

@arvidtp

I set it to 8.4v.

I'm not quite sure what you mean by "I'm assuming the DC input to the DC coupler needs to be regulated"

The dc coupler (the bit that looks like a battery and goes into the camera) just feels like a hollow box that connects the wires from the coupler to the camera appropriate contacts. That's why we need the Dynex thing to power it at 8.4v.

Make sure the seller includes the 4.75x1.75mm tip, that's the one you need for this. I had to get the seller to send it to me after the adapter and other tips arrived.

@evero
1. No - input voltage is too high?
2. Looks ok - no mention of efficiency though. I think it's a pretty inefficient circuit.
3. This looks like the efficient variety (can't remember all the details now, it was ages ago I looked at this stuff)

I would get something like this as mentioned in the other thread:
http://www.ebay.com/itm/5V-9V-12V-USB-Super-Capacity-Recharge-Li-ion-Battery-/280726420534?pt=US_Batteries&hash=item415c993c36

Unless you've already bought the one without 9V output?

@evero
For anyone feeling adventurous, I used a very small Texas Instruments circuit to convert my ~12V battery pack to 9.3V for my GH1. Depending on what country you are in, you might be able to obtain a free sample from Texas Instruments (I was in the UK when I obtained mine) I also have a 9V output which runs the camera just fine.

More details here: http://jordanofoz.com/?p=20

@markmark1 - Do you set the Dynex charger to the 8.4v setting? I'm looking at getting one. Here are the specs: http://www.dynexproducts.com/cms/documents/DX-UA_09-0318_QSG_V1_EN_Final%20Press.pdf

and I'm assuming the DC input to the DC coupler needs to be regulated, right?

I have built my own battery adapter which allows me to use Sony F970 batteries with my GH2. I have an electrical engineering background and I was very careful about how I designed my adapter. As has been stated the fully charged voltage of many batteries can be well excess of the rated voltage. While this in of itself may not cause damage to the GH2 I had no intent of letting my prized little GH2 see anything other than a nice clean compatible voltage level.

So I decided to use a DC-DC converter in my adapter that steps the voltage from the battery down a little to be more compatible with the GH2's normal operating level. A Sony F970 has a start voltage of about 8.4 volts and drops to 7.4 for a considerable amount of time. The problem of course is that most DC-DC converters need some amount of "pressure" or voltage difference between the input voltage and the regulated output voltage. I wanted to supply my GH2 with a stable voltage of some level for the longest period of time.

To do this I first ran a normal Panasonic battery down to almost empty. I then measured the voltage output from the Panasonic battery and found that at the last Bar on the battery gauge the Panasonic battery was reading 6.8 volts. Using this voltage I adjusted my DC-DC converter to output 6.8 volts. By doing this I know that my GH2 will never see more than 6.8 volts of power from my Sony F970 battery adapter. So when I plug in a fresh F970 with a voltage level of 8.4 volts my adapter steps that down to 6.8 volts and holds that voltage for a very long time.

In testing I have been able to run a stock GH2 for 8 hours of virtually uninterrupted recording. That was having it record at 24P H looking at a TV screen for changing content. Each time the card filled I would format the card and start recording again. I think 8 hours from one Sony F970 battery is pretty good.

The tough part was the actual connection to the GH2. I used a cheap third party battery to create my own power adapter. I found of course that the GH2 does not like to get just a voltage levels it also needs a special signature from the battery to allow the camera to operate. I had to incorporate a small mother board from the third party battery into my adapter as well. This was fairly tricky as there is little room between the contacts of the normal GH2 battery connections.

I have never done a DIY video on my adapter for this reason. I am too concerned that the connections I used via the old third party battery were to delicate for many to do with out potentially damaging their GH2. I use my adapter often and love the long run times.

In general please be careful when trying to adapter any type of power system to any camera or device. Always check the polarity then check it again, and check it again. You can check it a million times, you can be wrong only once.

CobyD: I orderd a Dynex universal camcorder like this one: http://www.ebay.com/itm/Dynex-Universal-Camera-Camcorder-AC-DC-Power-Adap-DX-UA-/260765841802?pt=Batteries_Chargers&hash=item3cb6daf98a#ht_1450wt_1141

It works! (I checked the polarity before I used it)

If anyone orders one, make sure it comes with the straight tips, the ones that came with mine were only the speciality ones, but after I contacted the seller, they sent me the correct one (as pictured far left bottom, dimensions 4.75mmx1.75mm)

Or use a potato. I remember from my schooldays that if you stick a couple of wires about 1cm apart into a potato, the potato will turn blue around a wire of one polarity. Can't remember which but I'm sure I have a potato somewhere so I could test it and report back. Of course, you need to carry a potato around with you and wait a bit for it to work, but that's a small price to pay. Can't be fried or sauteed, has to be raw.

UPDATE The potato turns green around the negative wire. So you need never worry about polarity again!