Charge Rates for NiCads
P van Huyssteen - Ingenieursnetwerke
batteries like AA,A,C,D,etc.
I am trying to build a charger capable of charging the whole range of
batteries.
Thank you
Pierre van Huyssteen
Joern Yngve Dahl-Stamnes
>Does anybody have a list of the charge rates of the different size NiCad
>batteries like AA,A,C,D,etc.
>
>I am trying to build a charger capable of charging the whole range of
>batteries.
From a table I got:
Type ANSI Capasity C5mAH
------------------------------
AAA 220
1/3AA 110
1/2AA 350
AA 700
3/2AA 800
2/3Af 600
4/5Af 1200
Af 1400
7/5Af 1700
1/2Cs 750
4/5Cs 1200
Cs 2000
5/4Cs 2300
C 2800
1/2D 2300
2/3D 2500
D 5000
F 7000
SF 10000
------------------------------
Note that this is the capasity when the battery is discharged over 5
hours time period.
When you shall charge a battery, you should use a constant current
source which give 0.1 C5mAH. If you have a C cell battery, the charge
current is 2800 mAh * 0.1 = 280 mA. This will charge your battery in 10
hours (if there is no losses at all). But since some of the energy is
lossed, you have to increase the charge time to 14 - 16 hours. This
charging method will not harm your batteries, but you should disconnect
the batteries after 16 hours.
Hope this help.
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* I went back to my mother, * Joern Yngve Dahl-Stamnes *
* I said, "I'm crazy ma, help me!" * University of Trondheim *
* She said, "I know how it feels son, * The Norwegian Institute of Tech. *
* 'cause it runs in the family." * Division of Physical Electronics *
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Jose Velez
It is very difficult to give you an exact list of charge rates of common
sized batteries. This is because even for the same size (example: AA) they
have different capacities (500mah, 600mah and even 1Ah) and the charge rate
(at least for maximum life) is usually 1/10 of the nominal capacity for a
period of 15 hours (you can shorten the charge duration incrementing the
current and shortening the time... at the expense of battery life!)
Any way, the most common current are:
50 ma for AA batteries
500 ma for ?? (medium sized...:)
1500 ma for D size batteries
Hope this helps
Jos'e Velez
r...@trsvax.tandy.com
Charge rates are defined by the amp-hour capacity of the battery.
If you want a safe charge, but one that takes 12-14 hours, charge
at a C/10 rate, where C is the batteries amp-hour rating. For example,
most AA batteries now are .65 A-H batteries. So, to safely charge them,
you would apply 65 milliamps. At a C/10 rate, most batteries can dissipate
the heat and recombine the oxygen generated during overcharge without
venting electrolyte, so leaving them on the charger for longer periods
is not typically a problem.
There are some systems available (notably the ICS1700 Ni-Cad Battery
Charger Controller from Integrated Circuit Systems) that allow you
to charge at a faster rate (the ICS1700 works at .5C, 1C, 2C, and 4C).
To do this, however, you must carefully monitor the battery
voltage during charge, and turn off the charger (or reduce to a
trickle charge) as soon as the charge voltage peaks. Otherwise,
you end up cooking the electrolyte out of the battery.
Typical battery capacities are: C/10 rate is:
N -- .15 A-H 15 mA
AAA -- .18 A-H 18 mA
AA -- .45. .65, or .85 A-H 45, 65, or 85 mA
9V -- .065 A-H 6.5 mA
C -- 1.6 or 2.0 A-H 160 or 200 mA
D -- 1.6 or 4.2 A-H 160 or 420 mA
Paul Opitz
Radio Shack Publications