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Replacement pcb mount nicd battery

Rangytangy

Jan 18, 2022
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Jan 18, 2022
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Help needed sourcing a replacement Varta nicd 3.6v 280 mah pcb mount 3 pin battery, seems all I can hold of from manufacturers are either 60 mah or higher 120 mah nmh not sure that the instrument it has come out of will be capable of charging it , hope someone can shed a little light on sourcing one of these .
 

Rangytangy

Jan 18, 2022
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Jan 18, 2022
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Thanks for your swift reply photo attached kindest regards.

Clipboard01.jpg
 
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Rangytangy

Jan 18, 2022
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Jan 18, 2022
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dave9

Mar 5, 2017
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You could measure the voltage and current to it to see what the charging circuit is doing (with a high ohm resistor load). Depends on the device, but a common NiCd stack of that capacity, would be trickle charged off 5V rail with a current limiting resistor in series, or whatever > ~4.4V rail is available on the PCB.

If you make up a number, say 8+mA target charge rate on a 5V rail, might have around 100 ohm resistor in series already, so could add another 400 ohms or so across the terminals and measure the current and voltage.

Is there room for a larger battery pack? Since NiMH is less tolerant of the trickle charging, you could offset this by using a larger cell size, like 3X AAA NiMH in a battery holder wired to the PCB, or there may still be some stock out there of AAA NiCd as it wasn't that long ago I saw some cheap generic landscape lights that used NiCd AAA... though I don't know about the quality, if the NiCd are now only made by 2nd/3rd tier manufacturers instead of major brand like NiMH are.
 
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