Hello
Why most battery charger that charge nickel cadmium or nickel metal hydride batterys from size AAA ,AAA,C ,D.
require that you charge two battery at same time?
When you try to charge One battery at a time the battery charger will not work.
Second question looks like most battery charger ,charge battery in parallel.
Third question is there a battery charger that charge battery in series size (AA) ,(D).
Thank for infor.
mrel

 

Two cells are needed in the charger because they are charged in series.

 

The chargers put out almost 4 volts. If you tried to charge 1 battery, it would kill it. Cheaper chargers keep the prices down by not adding additional logic and regulation to check on the numbers of batteries. So they require a minimum of 2 batteries. Often these types of chargers will drain the batteries prior to the charging cycle, so if you have one charged battery and one not, it will drain the batteries to around 2v then start the charging cycle.

 

Thank for the reply Audioguru,Retched.
Retched I am confuse on your on the reply on nickel cadmium or nickel metal hydride batterys from size AAA ,AA,C ,D.
You mention battery charger , drain battery to 2 volts how would that be possible since AAA ,AA,C ,D batterys when fully charge only hold 1.3 volts.
Audioguru you mention battery are charge in series,why most battery charger have battery in holder facing in a parallel diection , positive same diection and negative same diection ,looks like charge in parallel..
mrel

 

A Ni-Cad or Ni-MH cell is 1.4V to 1.5V when fully charged and is still in the charger.

Two cells can appear to be facing the same direction but are actually wired in series.

 

Parallel is not the same when regarding angles and electronics. Serial means the all the electrons traveling through one component will travel through another. So the lines are not shared. in battery chargers, the batteries are lined up in series, but bent to fit in the case.

Parallel circuits don't need to run side by side, like the geometry definition. Parallel means the electronic path that go through one point are split to two or more points.