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Using external battery with GM1?
  • umpump

    I've got a GM1 I like for video work - the sensor is really nice for HD and the PITA controls aren't an issue once you put a lens with an aperture ring on - but the battery life is, of course, awful. I'm thinking of getting a dummy battery on ebay. It seems to me that if do this then I should be able to run the camera off an 8.4V airsoft or bike light battery. Am I missing something?

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  • Vitaliy_KiselevVitaliy_Kiselev

    @ump

    I think not, you will need to retain chip inside.

    Can get third party battery and remove all internals carefully except chip and solder new wires and connector.

  • umpump

    Perhaps I'm missing something, but why would I need to retain the chip (presumably in the battery usually used) if an external power coupler/dummy battery is in place? The GM1 is designed to work with external power - specifically 8.4V DC from the main adapter via the coupler. If the coupler is getting 8.4V DC, then it shouldn't it be happy? There shouldn't be a way for the camera to tell the difference between an adequate external battery and the feed from the mains converter.

    (I think the role of the chip is to tell the camera to operate at the lower voltage of the standard battery?)

    But thanks - I'll experiment and see what happens. Success would turn GM1's into very useful little components for rigs emulating the ergos of an 8mm or 16mm camera - add a pistol grip and a simple magnifier for eye relief and away you go...

  • Vitaliy_KiselevVitaliy_Kiselev

    @ump

    If it is designed, I am wrong. In this case original battery has lower voltage than 8.4V.

  • umpump

    Yes, the regular battery is definitely lower. I just found this

    > https://www.dpreview.com/forums/post/59722696 A dpreview poster (RobertG_Berlin) mentioned that Panasonic cameras will measure the voltage, and if it is in the range for Li-ion batteries, it will require the battery to be chipped to identify it and the camera will say you can't use this battery if the voltage is 8.4v or less and the battery is unknown. But if the voltage is 8.5v or higher, it will assume it is being powered via an external source <<<

    ..I suspect the limit is 8.4 rather 8.5 though - if only from the text on the GM1 base plate.

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