I happen to own 5 batteries for the GM1. I bought the GM1 at a good price and it came with the stock Lumix battery. This is a smallish battery at only 680 mAh, a rather paltry amount of energy for a camera as sophisticated as this is. So I bought a pair of aftermarket batteries, and then did it again as the result of a “senior moment” … a term I despise and thus substitute with “brain fart” …
Anyway … here are samples of each battery with the protective mother hen in the background …
The battery on the left is the DTSE and the one on the right is a FOSMON. All work well in the camera and all carry a decent charge. Both aftermarket batteries claim a substantial 1000mAh, to which I call bullshit. The FOSMON does outlast the Lumix on video, but only by a tiny percentage. The DTSE batteries don’t get as much use and thus they probably need a few more cycles to get up to full capacity.
I basically set the GM1 on a tripod and set it to 24p at 28 Mbps with exposure values of 3200 ISO, f/3.5 and 1/50 shutter (180 degree.) This was done in a dark basement and there was no movement, so recording was extremely consistent from cam to cam.
I only approximated the total times by adding each file’s length, and here they are:
| Battery | Recording Time |
| Lumix | 108m |
| DTSE | 92m |
| FOSMON | 113m |
The FOSMON batteries are obviously a good value. The DTSE not so much.
Note also that sleep mode seems to work with both.
