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nicad battery cycling and capacity question

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nicad battery cycling and capacity question

Old 04-13-2017, 08:34 PM
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bansheeman1
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Default nicad battery cycling and capacity question

I have a 4.8V 600mah battery and a 9.6volt 600mah. Just bought them. What should the capacities be after cycling and charging. Meaning what are good acceptable mah numbers to be considered useable. I thought we flew off the extra capacity above 600mah. I am rusty having been out of the sport for a while. I am trying to verify the packs are good. thank you for your help.
Old 04-14-2017, 02:50 AM
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1QwkSport2.5r
 
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If they charge to capacity and hold a charge, I'd say they're good. Does your charger show you how much of a charge the battery takes?
Old 04-14-2017, 03:08 AM
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Charge and then discharge them. If the discharge reads 80% (480 mah) or better of the rated capacity then the batteries are OK to use.
Old 04-14-2017, 08:58 AM
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bansheeman1
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My cycler/charger is the old Alpha 4 by Litco. It shows only discharge mah. The discharge rate is 500mah or 333mah. The 4.8 read 628mah first cycle and the 9.6 read 177mah.
Old 04-14-2017, 10:20 AM
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All Day Dan
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Measure the discharge capacity at a cut off voltage of 1.1 volts per cell or 4.4 volts and 8.8 volts. Do this three times. It will be less than the rated capacity. About 80%. Discard them when you measure 20% of their initial capacity you measured or two to three years old whichever occurs first. Deep cycle them every three months if they are being used or once a month if they are not. Dan.
Old 04-15-2017, 04:00 AM
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Steve Percifield
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You need to do 2 or 3 discharge/ charge cycles to format them and wake them up. Being new both should charge and discharge some where around 600mah. The charger settings, cable resistance, and a lot of things will affect the results , so anything close is Ok. It's more important that they are consistent. The 80% rule is the cut off. MAH will seldom exceed rated value.

You are thinking of voltage, which will exceed nominal voltage after a charge.
Old 04-15-2017, 07:45 AM
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Rodney
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The rate of discharge is important; the faster you discharge the lower the capacity you will read. If I remember correctly, you should discharge at 0.1C (60 milliamperes for your 600 mah cells) down to 1.0 volts/cell if comparing to factory specs, any faster and you will get a lower reading. Also be sure to charge at 0.1C for at least 15 hours between charges to insure that all cells are balanced. If you charge at a higher rate and/or use a peak detecting charger chances are that all the cells were never fully charged.
Old 04-15-2017, 08:38 AM
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All Day Dan
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Rodney, you have a good point. None of the modern chargers have a constant current option for NiCads. How do you get around the peak detector charging to get to the 15 hours needed for a full charge? Dan.
Old 04-15-2017, 11:37 AM
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A. J. Clark
 
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If your charger switches to a trickle charge after the peak charge you can set the trickle charge to .1c
Old 04-16-2017, 08:37 AM
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I have a 4-cell NiCd pack that I am guessing is on its last leg. I also have a 5 cell NiMh pack that probably has a dead cell in it too. Where is the best/most ideal source for small NiMh cells? It seems that the quality of these NiCd and NiMh cells is hit or miss in a retail setting... I'd like to convert to using LiFe cells, but I know some aircraft receivers don't like much over 6v if even that much. So NiMh is probably the best route to go, I just need a reliable source of quality cells to make some receiver packs. The NiCd cells I have are Cadnica 600MAh and the NiMH pack are 1600MAh from Venom racing (RC car outfit).

I tried the discharge and recharge cycle with the charger - the NiCd pack peaked at 4.1v after one cycle charged at .1A (lowest the charger will do - it took 359 minutes to do the discharge and charge cycles together). The NiMh pack peaked at 5.57v after a discharge/charge cycle which was the same voltage after just a normal charge at .5A. The charger I'm using is the Hobby People Activator; model 60 or 80, I forget.
Old 04-16-2017, 08:40 AM
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Rodney
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You might want to check out" www.angelfire.com/ny2/kath/rc.html "for lots of good info on how to make chargers and much more for most any specific task. A really useful web site for many items.

Last edited by Rodney; 04-16-2017 at 08:41 AM. Reason: correct address

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