How to discharge Ni-Cd battery

I am going to show you a discharge Ni-cd Battery circuit. Why should you use this?

Ni-Cad battery has advantages that rechargeable to reuse again. And cheaper than other types of rechargeable batteries like Ni-HM battery.

I love NiCd batteries. Because they are mains 4 reasons:

  • Hard to damage more durable than lead-acid or lithium batteries.
  • Far more tolerant towards long deep discharge cycles.
  • It can perform well under tough conditions.
  • Have high energy like with alkaline batteries (cannot recharge).

But they have an important disadvantage is a memory effect. Before charging this battery. It needs to have power is zero only.

how to Discharge Nicad battery

If you charge it while little energy remaining. It will cause the memory effect status.

There are 2 disadvantages:
It will remember that voltage or energy level. Resulting in not being able to release the maximum energy.
And importantly, the lifetime of this type of battery is shorter, too.

Read Also: Simple NiMH NiCd Battery Charger circuit

A good solution is using the Discharge Nicd battery circuit at all times. Before charging with a normal battery charger.

Prohibition: Do not cause the battery to short-circuit. It will damage the battery.

We have 2 circuits to do:

Simple circuit with relay

This is simple ni cad battery discharge for 6V (1.2Vx4). This circuit will help increase its lifetimes of more.

How it works

When we connect the batteries 6V(1.2V in series) to discharge.  Both diodes D1 and D2 in series, they will detect a voltage of the battery. 

Recommended: Simple 1.2V AA battery Solar charger circuit

If the battery has a voltage more 1.4V. It makes RY1 run. A contact switch from NC into NO. It makes L1 flow up until the voltage is lower down.  Adjust VR1 to stop working to contact NO to NC. Then, the L1 goes out. It finished the discharged process.

simple discharge ni cad battery using Relay and lamp

Discharge Ni-Cd battery in many voltages

We can use this circuit for many levels of the battery from 3V to 15V.

discharge Ni-cd Battery

This circuit is used to discharge the battery at a voltage bias to Q1 adjusted using VR1 serves volt bias to the base pin of Q1 is appropriate to bring the battery if the battery has voltage remaining Lamp. Light up until the battery runs out Lamp will gradually vanish if there is no battery power remaining lamp will not start.

Parts you will need

VR1: Potentiometer 1K
Q1: TIP3055, NPN transistor
L1: 12V 10W light bulbs

Caution: In use, if possible, Q1 should be mouth attached to the heat sink, too.

CR: image by StonyCreek

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