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#1
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How long to charge AA NiMH?
I have a Sony BC-CS1 charger. Apparently the charging light never goes
out. How long should I charge a AA NiMH battery? Thx. Ed |
#2
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How long to charge AA NiMH?
Until it is fully charged. When charged with a fairly high current (greater
than about 1/4th of capacity), NiMH batteries start to heat up, (most of the energy is converted to heat) and the terminal voltage drops slightly. Decent chargers will detect this state for every single cell and either switch the charge current off or switch to trickle charge for maintaining the charge. I do not know about the Sony BC-CS1. For example the better models from GP and others work fine this way. As a rule of thumb, a fully discharged new NiMH battery can be charged with 1.4 times its capacity before overcharging sets in. "Ed Wicks" schrieb im Newsbeitrag ... I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed |
#3
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How long to charge AA NiMH?
In article ,
Ed Wicks wrote: I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed Until it is charged. How long does that take? Take the mAh rating of the battery. Add 30% and divide that by the chargers output. That is how long it takes that charger to recharge that battery if that cell is fully uncharged. -- To reply no_ HPMarketing Corp. |
#4
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How long to charge AA NiMH?
Ed Wicks wrote: I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed The NiMH batteries are known for high tolerance to overcharging. If you charge your battery for 8 hours, it will definetely be charged (there are no other chargers which are made for charging for longer). |
#5
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How long to charge AA NiMH?
Bob Salomon wrote:
Until it is charged. How long does that take? Take the mAh rating of the battery. Add 30% and divide that by the chargers output. That is how long it takes that charger to recharge that battery if that cell is fully uncharged. Close but not quite. The "Operating Instructions" sheet packed with my Sony BCG-34HUF charger specify a 15 minute charge time for 2500mA NH-AA batteries. The charging output is specified as 7.5 amps at 5.6 volts DC. You formula calculates 26 minutes. If you deduct the 30% instead of adding it, the formula calculates 14 minutes. Did you mean to say "add 30%" or should it have been "subtract 30%" or does this particular charger just work faster than your formula? |
#6
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How long to charge AA NiMH?
Ed Wicks wrote:
I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed Hi... That charger is little more than a trickle charger; it charges at only 70 mil's. So if you were charging 2500 mA batteries from "empty" to completely topped up, it would take a little more than two days to finish. Take care. Ken |
#7
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How long to charge AA NiMH?
On Thu, 28 Dec 2006 08:20:45 -0500, Ed Wicks wrote:
I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed How long have you waited for the light to go out? Some old chargers have lights that don't indicate when the batteries have reached a full charge, and use the light only to indicate that the charger is powered on and is still charging, even if the batteries have been charged so long that they're now being overcharged. A figure can't be given for that charger unless you know the actual capacity of the AA batteries. The BC-CS1 is an old, *slow* charger that took 13 hours to charge 1,750mAh AA batteries. If you have the original AA cells that came with the charger, they're probably pretty old and have lost a lot of their original capacity. So if by now they're providing only 1,200mAh, they'd charge quicker, taking about 9 hours to reach full charge. But if you buy new 2,700mAh batteries, they would need just over 20 hours to complete charging. Such old chargers usually had timer cutoffs, so that they might stop charging after about 15 hours, and the 2,700mAh batteries wouldn't fully charge with only a single charge cycle. If the charger's charging light went out at 15 hours, the 2,700mAh batteries would only be 75% charged. You should probably get a new "smart" charger, one that knows when the batteries are fully charged and stops charging at that point, instead of continuing to charge until a time limit is reached. They'll be able to deal with modern high capacity NiMH cells, and depending on the model, can fully charge AA cells in less than a couple of hours. There are some very high current chargers that can fully charge AA cells in as little as 15 minutes, but the NiMH batteries would probably last longer if you get a gentler charger that takes an hour or more to finish charging. |
#8
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How long to charge AA NiMH?
On Thu, 28 Dec 2006 08:20:45 -0500
Ed Wicks wrote: I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed Here's the summary I wrote up back in 2002, including a link to definitive backup material by Marc Venis and a handy Java charging time calculator: http://paulngail1.home.comcast.net/batteries.html Charging time does matter. If your charger is not one of the newer automatic types, you must know the charging current and the capacity of your batteries in order to calculate the approximate time to a full charge. If your charger does not have its charging current listed on its label, throw it out and buy a better one. Paul Allen |
#9
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How long to charge AA NiMH?
Ken Weitzel wrote: That charger is little more than a trickle charger; it charges at only 70 mil's. So if you were charging 2500 mA batteries from "empty" to completely topped up, it would take a little more than two days to finish. LOL I got my first N-Mh AA 2600mA cells last week and only have an old Uniross charger which states it charges at 150 mA. I make that around 24.6 hours for a full charge! Must get a modern charger.... The rule of thumb I used with slow charge Ni-Cd's is capacity/10 for 14 hours. |
#10
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How long to charge AA NiMH?
Ed Wicks wrote:
I have a Sony BC-CS1 charger. Apparently the charging light never goes out. How long should I charge a AA NiMH battery? Thx. Ed I have 2500 NiMH batteries which take 27 hours to charge in my 140mA charger. Ron -- And it really doesn't matter if I'm wrong I'm right Where I belong I'm right Where I belong. Lennon & McCartney |
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