Flash Gun...the batteries??

Discussion in 'Digital Photography' started by wheelhot, Oct 10, 2009.

  1. wheelhot macrumors 68020

    Joined:
    Nov 23, 2007
    #1
    Hey,
    Alright, It seems I heard many people are saying that the Sanyo Eneloops and the Maha Imedions are better then the normal NiMH (eg: Powerex) batteries, from what I can see the only reason why its better because it can hold the charge longer over a period of non usage but how does that make it better then the regular NiMH during flash usage? Heck, its mAh is 2000 (eneloop) and 2100 (Imedion) vs 2700 commonly found in the usual NiMH battery.

    And well between Eneloop and Imedion, I can see that Imedion has higher mAh compared to Eneloop but does that make it better?
     
  2. mahood macrumors member

    Joined:
    Aug 6, 2009
    Location:
    UK
    #2
    The mAh figure is a measure of stored energy - you can imagine if you draw 2000 milliamps constantly, a 2000mAh battery will last for one hour. In that sense, higher is better - you can supply more current for longer, which is a good thing. This means fewer battery changes, more shots between recharges etc. It's unlikely to be noticed in flash recycle times, as they all supply enough power - you'll just feel that you get more shots from the higher value cells.

    As you say, the Eneloop and Imedion 'hold' that charge longer - ideal for something which sits in your camera bag for weeks between uses. They're called 'low-discharge' and are explained here: http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery

    A typical NiMH battery can lose up to 50% of its charge in a year (most of that at the start - the rate tails off quickly), while LSDs lose between 15% and 30% - so it's not a big deal unless you're leaving them alone for a long time. Estimates are that a NiMH cell loses around 2% of its charge per day at normal temperatures, so if you use your kit regularly you'll not notice a difference. (If you replace 2800mAh NiMHs with 2000mAh LSDs, you'll only win if it sits around for nearly 3 weeks before you use it.) they're mostly designed for lower current applications like clocks & remote controls where they sit around for ages doing almost nothing.

    For a review and more info: http://www.stefanv.com/electronics/low_self_discharge.html

    I use 'normal' 2800mAh NiMH cells, and get in the habit of recharging them before a major shoot, (afterwards too if I use them a lot) and carry standard non-rechargables in the camera bag (which last up to 5 years) just in case.

    Hope this helps.

    Mark
     

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