I have some Ni-Cad batteries (12 Volt) and a 12 Volt lead-acid charger from a security system. I'm thinking of a 12 Volt UPS power supply. The charger is set for trickle charging lead acid. Would anyone know the proper terminal Voltage for a trickle charged Ni-cad?
Tnx, Lewis

Lewis,
I've found 2 volts/cell to be typical of a Nicad under charge, but beware a trickle charge for a LA is not the same as a Nicad. Trickling an LA may be a few amps, whereas nicad might be a few milliamps, depending on the batts. Open cell volts will drop to approx. 1.5 volts right off the charger, then to 1.2v under load. Best to get real specs on the nicad in question

marv

:I have some Ni-Cad batteries (12 Volt) and a 12 Volt lead-acid charger from a security system. I'm thinking of a 12 Volt UPS power supply. The charger is set for trickle charging lead acid. Would anyone know the proper terminal Voltage for a trickle charged Ni-cad?
:Tnx, Lewis
:

Lead acid batteries are open vented, and so gasses can escape. NiCad batteries are sealed, and so must not build up any steam, or else they will explode. This is why they often take over 16 hours to charge. The charger for my cordless shaver feeds current to one 1.2V NiCad through an LED that also serves as a 'charge' pilot lamp. It may even serve as a rectifier. I don't recall. Anyway, the current is VERY low. Charging a NiCad at 1 ampere or more will likely blow it.

My grandfather had a charger that had a diode and a 7 watt C7 bulb in series with the AC line. Evidently the current draw of the 7 watt bulb was enough to charge the batteries from 120VAC.

T.

T.

:Lead acid batteries are open vented, and so gasses can escape. NiCad batteries are sealed, and so must not build up any steam, or else they will explode. This is why they often take over 16 hours to charge. The charger for my cordless shaver feeds current to one 1.2V NiCad through an LED that also serves as a 'charge' pilot lamp. It may even serve as a rectifier. I don't recall. Anyway, the current is VERY low. Charging a NiCad at 1 ampere or more will likely blow it.
:
:My grandfather had a charger that had a diode and a 7 watt C7 bulb in series with the AC line. Evidently the current draw of the 7 watt bulb was enough to charge the batteries from 120VAC.
:
:T.
:
:T.
:These batteries came from a DC-9 emergency light pack. In the plane, there was a resistor connected to a 28 Volt DC bus, and were constantly trickle charged through a resistor whenever there was power on the airplane.
Whatever Voltage I turn the lead-acid trickle charger to, the current will go to zero after a while, and the battery seems to be fully charged. I was wondering if there was an optomal Voltage like there is for a car battery, like 14.4 Volts, I think. I put a ni-cad in my security system in place of a lead acid, and it worked fine for about a month without even getting warm, and tested fine under load when the battery test button was pushed.
Lewis