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AA Ni-MH battery charger output current mA
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jayboydog:
Thinking about different cheap AA Ni-MH 1.2v battery chargers.    two look identical. both have 120v AC input.   different brands yet both have label reads "200mA x 4".  I measure current mA by opening the circuit with a piece of paper between charger and battery then close the circuit with meter probes adjacent to each side of the paper,  but each outputs different mA to each battery depending on 1,2,3,4 batteries charging at same time.  #A  120mA    90mA    72mA    60mA,   #B  60mA   60mA    60mA   60mA.

what is "200mA x 4" supposed to mean?


A third charger is called "smarter".   will charge 1,2,3 or 4 batteries at same time.  I do not get a mA output as whichever individual channel I am in series to measure mA causes "error" on the charger display for that channel.  the other batteries continue charging.  why is the meter measuring mA in series with a battery causing "error"?
dacman:
"Smart" chargers can usually charge both NiCad and NiMH.  They take measurements on the batteries, they do not just source current.  Placing the leads in series would not be something the charger would understand.
Audioguru:
Your meter measures current by connecting a resistor in series and measuring the voltage across the resistor. A smart charger sees the battery with too much resistance in it and shows an error.
IanB:

--- Quote from: jayboydog on April 23, 2018, 01:37:07 am ---Thinking about different cheap AA Ni-MH 1.2v battery chargers.    two look identical. both have 120v AC input.   different brands yet both have label reads "200mA x 4".  I measure current mA by opening the circuit with a piece of paper between charger and battery then close the circuit with meter probes adjacent to each side of the paper,  but each outputs different mA to each battery depending on 1,2,3,4 batteries charging at same time.  #A  120mA    90mA    72mA    60mA,   #B  60mA   60mA    60mA   60mA.

what is "200mA x 4" supposed to mean?
--- End quote ---

Whatever the marketing people want it to mean  :)

A more useful number to look at is how many hours it should take to charge a typical battery. If the charger is really charging at 60 mA then a typical 2000 mAh battery would take about 36 hours to charge, which is silly. Nobody would wait that long.

Make and model number of the chargers would be helpful.
Circlotron:

--- Quote from: IanB on April 23, 2018, 03:46:26 am ---would take about 36 hours to charge, which is silly. Nobody would wait that long.

--- End quote ---
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