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- Nicad charger
June 25, 2007, 1:18 am
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Re: Nicad charger
You will need to know the recommended charging current and overhead voltage
for charging the particular battery type. The charger will have to be
properly regulated for both the voltage and current, and have the proper
safety design in order to not overcharge the battery.
Many of these batteries have thermo sensing devices that feed some logic
circuits in the charger. This is to cause the charger to shut down in the
case if the battery overheats.
In working in this industry, I have seen injuries and fires started from
improper charging of NiCad and Lithium batteries. Read the warnings on these
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Re: Nicad charger
If it would be an old fashioned standard NiCad and you don't know
anything more specific, assume that the charge has to be
14 hrs at 10% of the capacity, when fully discharged.
i.e. a 1 Ah Cell will be charged with 0.1A for 14 hrs.
10% current of this again, can be safely applied as trickle charge 24/7
to keep the battery full and ready to go (1% of capacity).
Your battery has 8 cells with nominal 1.2V*8 = 9.6V. When fully charged
it will have 8*1.4V = 11.2V
Measure the current when fully charged with 12V applied. If it is like
the trickle charge (about 1% of capacity) you could just switch a light
bulb in series that has about the power of 2.4V*[10%of capacity].
It will act as a constant current source over a fair time of the
charging process, and also as a current limiter.
Make sure that your power supply is rated for your charging current.
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