HP41 Rechargeable Battery Pack - three pins ?


Hi All,

I have just aqcuired a 41C with rechargeable battery pack, but it has three pins instead of the normal two pins for the charger. Does anyone know what the extra (middle) pin is for ?, and can I charge this with a normal 41c battery charger ?



I wonder if that middle pin was designed to be a 'ground' pin at one point.. The AC plug is conspicuously missing a 'case' ground.


I am not sure the answer, some senior told me before , the different between two and three pin battery was the three pin battery could be used the AC charger power to hp41 directly.It also need 3 pin AC charger. Similar to classic series 45,65,67,80.The two pin battery can not used the AC charger power directly,it just charged the battery only when it plugged the AC charger.

If it is not correct answer, every senior user please tell me the true of the different between these two battery.

Edited: 4 Mar 2010, 3:46 a.m.

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