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Old May 29, 2003, 3:08 PM   #11
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ehm which means what to me in this case :?

Sorry Steve must be having a slow day today - obviously excited bout my trip to Snowdonia - though weather forecasts don't look too promising
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Old May 30, 2003, 10:16 AM   #12
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Why don't you stick the same rating torch bulb across each battery at the same time, discharge each to the same level (bulb at same dim level - (be creative, use your cam exposure meter, with a spare set of batts!). Then put all 4 batts back in your charger noting which slots it goes into, until charge complete, remove them and repeat discharge test. If 1 cell is discharging faster, that suggests either it had less charge to begin with, or it is out of balance by not taking or giving up the same charge. Repeat switching batts in different slots.

I assume if I buy 4 batts at the same time (I date and number each one) that each will age at the same rate, if they are conditioned to start with. So your question is either the charger is not delivering a balanced charge to each cell(possible), the cam discharges in pairs, (unusual), something is wrong with the cell efficiency (possible). From a fully discharged cell, I would expect each to feel about the same temperature near to end of the charge cycle.

Most chargers cut back to trickle charge, somewhere near the charge end point, in time terms you could get quite a variation as the final lower trickle charge of tens of milliamps is used to finish off the charge. VOX
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Old May 31, 2003, 10:43 AM   #13
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Steve6, a fellow racer .

Most of the cells are indeed different.
When using a good loader this should however be no problem.
To make sure you could use a decharging loader, this will draw your batteries almost dry, leaving a bit of charge (totally drawn is very bad), but even then there can be a difference.

I use NiMh 1600Mah for my camera and 2100Mah for my transmitter when racing, I must honestly say that the batteries for the camera do behave different from my transmitter, so maybe some camera's do draw different from the batteries although that seems unlogical.

Anyway, nothing to worry about.
But DO use a decharger sometime, although it is said that NiMh do not have the memory effect and therefor don't need to be decharged I found out that when you decharge after 10-12 cycles the runtime increased remarkably with a total conditioning cycle.

Greetings,
Frank
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Old May 31, 2003, 3:00 PM   #14
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thanks for the feedback all

stefan
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Old Jun 1, 2003, 1:14 AM   #15
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Frank Doorhof

Very interesting info about the "decharging". I'll have to remember that.
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Old Jun 2, 2003, 10:56 AM   #16
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ehm which means what to me in this case

A load of waffle to say don't worry, it's ok and not too unexpected to have cells of different capacities.
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Old Jun 2, 2003, 11:12 AM   #17
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you could say that, but this is much more intressting....

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Frank
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Old Jun 4, 2003, 8:07 PM   #18
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I see the same mixed recharge times with sets of 4 AA Powerex 2000 batteries and a Maha 401 charger, using an HP Photosmart 850 camera. However, it is really only significant on slow charge. On fast charge, the difference is a couple of minutes at most.
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Old Jun 7, 2003, 6:52 PM   #19
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Quote:
Most chargers cut back to trickle charge, somewhere near the charge end point, in time terms you could get quite a variation as the final lower trickle charge of tens of milliamps is used to finish off the charge. VOX
And, if you put more charge into a battery (within reason that is), so what, it just gets a bit more hotter! Batts aren't like piggy banks, charge a batt twice as long and they don't get twice the capacity - the extra energy put in just ends up as heat.
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Old Jun 7, 2003, 10:40 PM   #20
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I thought the rule was that it was ok to put in more change than was necessary... but only if it was a small charge. If you use the full blast recharge power to an already charged battery you could damage it. Am I missing something? I always assumed this is why they switch to a trickle charge once full (that, and it keeps the batteries topped off.)
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