External battery for Panasonic GH2

I was looking for an external, cheap battery for the Panasonic GH2. After seeing these two videos


GH2 Custom Battery Solution from Phil Hover on Vimeo.



GH2 8.4v external battery test from Keylight on Vimeo.

I decided that I wanted to try myself. So I bought the DWM-DCC8 adapter and then looked on ebay for a cheap external battery. I found this pack from seller Am-slotracing and I can confirm that these batteries work very well. I had to change the connectors though, but anybody with some soldiering skills can do it (in my case I went to an electronics shop). To charge these batteries I use a GBC charger, code 38.0240.05 (I live in Italy).

At first I bought this charger, but it was broken (dead-on-arrival) and the vendor did not reply to my e-mail.
I cannot say how long these batteris last because they really last a lot; I bought two of them just in case.