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Thread: Charger Charging Voltage?

  1. #1

    Default Charger Charging Voltage?

    I just got myself a Energizer DUO USB Charger for cheap.
    I have to say it's a nifty usb charger, it came with an AC to USB adapter to plug it straight to the wall.

    I also have my Sanyo NC-MDR02NU, from an Eneloop battery package.

    Now, the charging specifications on the Sanyo charger is
    Output = DC 1.2V
    550mA x 2 (AA)
    380mA x 2 (AAA)

    Where as the Energizer USB charger states
    Output = 1.4V (DC Current Sign =) 550mA.

    That's all it says. What does the equal sign mean? The charge time specs says it can charge a 2000mAh Battery in 4 hours.
    I've emailed Energizer about the charge times and if it makes a difference, and does it send BOTH batteries 1.4V @ 550mA.
    The Eneloop USB Charger clearly states that it does send 450mA x 2 (AA).
    That's why i'm curious on what it charges the batteries at.
    I've yet to receive a response.

    What does the charge voltage difference make in a charger?
    Would the Sanyo charger charge faster than the Energizer DUO charger?
    Last edited by kay188; 12-18-2008 at 01:23 PM.

  2. #2
    *Flashaholic* Mr Happy's Avatar
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    Default Re: Charger Charging Voltage?

    The charging voltage doesn't really mean very much; it's just a nominal figure. The difference between 1.2 V and 1.4 V is just the difference between one label and another label.

    The charging current (mA) is more important as that tells you how fast it will charge the batteries. As a rough approximation you can take 1.1 times the cell capacity divided by the charging current as time to charge. It may be longer than this, but rarely less.

    What you can mainly tell from the voltage is if the charger will charge batteries singly or in pairs. A voltage of about 1.4 V normally means singly, whereas a voltage of about 2.8 V usually means in pairs.

  3. #3
    *Flashaholic* Marduke's Avatar
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    Default Re: Charger Charging Voltage?

    The solid/dashed "equal sign" is the symbol for DC (Direct Current)

  4. #4

    Default Re: Charger Charging Voltage?

    So there would be no difference between the Sanyo Charger and the Energizer Duo Charger?

    Since the Energizer Duo charger has a higher charge voltage, that doesnt mean it'll charge faster than the Sanyo charger does it?

    Also, having the Sanyo charger charge at 1.2v it also means it can charge a single cell?

    Since the specifications state the charge current for two cells, would the charge current double for charging a single cell to 1A from 550mA for 2 cells?

    Same question for the Energizer Duo Charger.

  5. #5
    *Flashaholic* Marduke's Avatar
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    Default Re: Charger Charging Voltage?

    Quote Originally Posted by kay188 View Post
    So there would be no difference between the Sanyo Charger and the Energizer Duo Charger?

    Since the Energizer Duo charger has a higher charge voltage, that doesnt mean it'll charge faster than the Sanyo charger does it?

    Also, having the Sanyo charger charge at 1.2v it also means it can charge a single cell?
    They most likely both charge using a voltage of 1.4-1.5v, despite what the back says. You could always measure what they actually do with a multimeter.

  6. #6
    *Flashaholic* Mr Happy's Avatar
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    Default Re: Charger Charging Voltage?

    Quote Originally Posted by kay188 View Post
    Since the Energizer Duo charger has a higher charge voltage, that doesnt mean it'll charge faster than the Sanyo charger does it?
    As Marduke says, just because it says 1.2 V on the label, that doesn't mean it charges at 1.2 V. It is most likely intended to indicate that the charger should be used for charging NiMH batteries with a nominal voltage of 1.2 V.

    The actual voltage required to charge NiMH batteries is 1.5 V or higher. If the charger can't actually produce 1.5 V it won't be able to charge the batteries fully. (In fact, 1.2 V is not enough to charge NiMH batteries at all.)

  7. #7

    Default Re: Charger Charging Voltage?

    I should really invest in a multimeter :P

    So i'm assuming charging one cell wouldnt double the charge time?

    It should shouldnt it? I recall looking at the Eneloop USB charger, and it states charging one cell is double the power so double the speed of charging, same with some chargers.
    I have this Pisen Charger i got from DX and it says from the manufacturer site that charging one cell is 1A where as 2 cells would be 500mA.

  8. #8
    *Flashaholic* Mr Happy's Avatar
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    Default Re: Charger Charging Voltage?

    Quote Originally Posted by kay188 View Post
    So i'm assuming charging one cell wouldnt double the charge time?

    I have this Pisen Charger i got from DX and it says from the manufacturer site that charging one cell is 1A where as 2 cells would be 500mA.
    It all depends on the charger. The charging speed is proportional to the current the charger feeds into the cell. Some chargers charge 1 cell faster than 2 cells. Some chargers charge 2 cells faster than 4 cells. Some charge at the same speed no matter what. You really can't generalize beyond what the instruction manual says for each individual charger.

  9. #9

    Default Re: Charger Charging Voltage?

    Does anyone know if the Sanyo USB charger can be used as an emergency power source for phones or mp3 players?

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