Tenergy T6278 Universal Smart Charger, Finally a Good Charger forC & D NiMH cells

Discussion in 'Digital Photography' started by SMS, Jul 9, 2008.

  1. SMS

    SMS Guest

    While there are numerous smart chargers available for AA and AAA cells,
    there is a dearth of smart chargers for C & D cells. C & D cells are
    finally coming down in price, and low-discharge C & D cells are also now
    available. I was looking for a good C & D charger because I use a lot of
    C batteries in Cree LED flashlights (the awesome Taskforce 2C Cree LED
    flashlight from Lowe's) for bicycle lighting.

    The individual charging channels with the LCD display for each channel
    is great, as is the discharge feature since periodic deep discharge is
    crucial in maintaining NiMH batteries. There's a fan to keep the
    batteries cool during charging, which also helps to prevent false
    over-temp detection which would prematurely shut the charger down.

    The power adapter is rated at 12 volts, 1.2A, so the charger could
    easily be used from a vehicle's 12 volt power source without the need
    for an inverter, but there is no DC charging cord offered so I'm going
    to fabricate one.

    One potential problem is that the charger stops automatically after six
    hours of charging (most good chargers will time-out just in case the
    Delta V charge detection or the over temperature detection doesn't stop
    charging). A fully discharged 10,000 mAH D cell will take about 14 hours
    to charge (extrapolating from the charging timetable (2.8 hours for a
    2000 mAH cell)). Even the 5000 mAH C cells that I bought would take
    about 7 hours to charge from a totally discharged level. The next design
    should either extend the maximum time, or include a switch to select 6,
    12, 18, or 14 hour cut-off.

    It also charges 9V NiMH batteries (usually 8.4V in practice), but it
    doesn't do the discharge function for them.

    I'm not sure if the end of charge detection is Delta V or Negative Delta
    V. Normally there would be a switch for Ni-Cad versus NiMH to switch the
    end-of-charge detection between Delta V and negative Delta V.

    All in all, it's the best C/D charger I've found, and I've looked at a
    lot of chargers. Of course it also charges AA and AAA cells.

    I ordered this charger from one of All Battery's eBay "Buy it Now"
    auctions (where the prices can be less than their web site, though with
    higher shipping). Since they are close by to me, and I go over to that
    area often, I called to see if I could do Will-Call and they said it was
    fine, though they still charged $4 "handling" for me to pick it up. I
    got the bundle with 8 5000 mAH C cells for $56, plus tax and handling.


    Note that if you close their page without ordering you'll get an offer
    for a 10% discount via chatting with someone (or something). This still
    was more than the eBay price for what I ordered so I declined.

    SMS, Jul 9, 2008
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