Power usage with battery grip?

Discussion in 'Beyond the Basics' started by cfusionpm, Sep 5, 2009.

  1. cfusionpm

    cfusionpm TPF Noob!

    Joined:
    Jun 21, 2009
    Messages:
    852
    Likes Received:
    6
    Location:
    San Diego, CA
    Can others edit my Photos:
    Photos OK to edit
    Just curious if there was any info on how batteries were used in a battery grip. If it holds two camera batteries, does it pull power from both of them equally? Or does it completely drain one then move to the second? Also, it seems the overall battery level indicator on the top screen represents the combined charge between them, is that accurate too?
     
  2. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    38,235
    Likes Received:
    5,007
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    Most grips use 1 battery at a time. There are some exceptions but not many.

    The way most battery operated things work, the battery voltages get added together. So 2, 1.5 volt AA batteries get added together (and used at the same time) for 3 volts. I just looked at one of my Nikon D90 batteries and it is 7.5 volts. Two used at the same time would be 15 volts, to much voltage for the camera circuits to handle.

    The D90 has a menu page to examine the charge level of each battery.
     
  3. cfusionpm

    cfusionpm TPF Noob!

    Joined:
    Jun 21, 2009
    Messages:
    852
    Likes Received:
    6
    Location:
    San Diego, CA
    Can others edit my Photos:
    Photos OK to edit
    How about the canon 50D? Is it burried in some sub menu?
     
  4. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    38,235
    Likes Received:
    5,007
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    I found out about the Nikon menu page by reading my camera Users Manual. Did you get one of those with your canon 50D? I don't shoot canon gear.

    Would you like me to download a canon 50D users manual and look for you? I know canon's user manuals aren't as, uh, complete as Nikon's. Let me know.

    Maybe a fellow canon 50d user will happen on your post and give some insight.
     
  5. pharmakon

    pharmakon TPF Noob!

    Joined:
    Aug 7, 2009
    Messages:
    365
    Likes Received:
    7
    Location:
    Western NC
    Can others edit my Photos:
    Photos OK to edit
    Not trying to start trouble, but the voltage only doubles if the batteries are wired in a series, wiring them in parallel would draw from both batteries at the same time without changing the voltage (assuming 2 batteries of the same voltage). The latter method would be much easier to produce without adding extra circutry to "switch" batteries once one runs low. I would think this is how the "budget" aftermarket grips would be as they don't have charge indicators so they probably lack the needed electronics for battery switching.
     
  6. camz

    camz No longer a newbie, moving up!

    Joined:
    Jun 11, 2009
    Messages:
    1,878
    Likes Received:
    284
    Location:
    Bay Area
    Can others edit my Photos:
    Photos NOT OK to edit
    Yes I think they use them both together at the same time and is assembled in series. I just ohmed out my grip and the positive pole of one battery compartment is connected to the negative mean they are both acting as one battery(series). So you have if you have the 50D with the BP-511A runs at 7.4 Volts. That makes 14.8 Volts with two so there's probably just a voltage regulator or sometype of step down transformer circuit in your camera that's converting the voltage to operation spec.
     
  7. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    38,235
    Likes Received:
    5,007
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    Yep. My reply was not really very clear was it. I was thinking about battery powered speedlights and cameras.
     
  8. Moglex

    Moglex TPF Noob!

    Joined:
    Jun 13, 2008
    Messages:
    578
    Likes Received:
    0
    Location:
    Whitstable
    Can others edit my Photos:
    Photos OK to edit
    Check to determine the voltage of the normal lithium battery.

    If the batteries in the grip add up to this voltage or just a little more, then they will be wired in series and both used together.

    If they add up to a lot more then they will almost certainly be wired partly in parallel to get near the required voltage.

    It would be odd if a grip had special circuitry to use one battery (or pair/group of batteries) before the another as that would not really provide any benefit.

    Requiring the user to manually switch batteries would make some sense as it would be an alert that half the available power had been used.
     
  9. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    38,235
    Likes Received:
    5,007
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    Pretty typical for Nikon grips. Holds 2 batteries, uses 1 at a time, no user intervention to swap to the fresh battery in the grip. Plus, the grip can be used with just 1 battery. You just have to be sure and put it in the right slot.
     
  10. Moglex

    Moglex TPF Noob!

    Joined:
    Jun 13, 2008
    Messages:
    578
    Likes Received:
    0
    Location:
    Whitstable
    Can others edit my Photos:
    Photos OK to edit
    Does it have a clearly visible display to tell the user that it's switched batteries?
     
  11. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    38,235
    Likes Received:
    5,007
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    The info is on a menu page in the camera.
     
  12. Moglex

    Moglex TPF Noob!

    Joined:
    Jun 13, 2008
    Messages:
    578
    Likes Received:
    0
    Location:
    Whitstable
    Can others edit my Photos:
    Photos OK to edit
    So it could quite easily make the swap without the user realising?

    Seems odd to put all that extra circuitry and logic into the camera so that it operates in such a way that the user may not be aware that they are running on the second battery.

    Do you happen to know what the advantage of this scheme is over simply running the two batteries in parallel?
     

Share This Page

Search tags for this page
battery grip batteries in parallel
,
battery grip consume not use power
,

battery grip power consumption

,
battery grip power consumption vs battery on camera
,
canon battery grip power consumption
,
canon battery power draw
,
how does two batteries in a camera power grip work?