Battery low voltage indicator Project

[lloydi12345]

Hi, I would like to create a battery low voltage indicator that will be connected to a microcontroller. Supposedly I'll be using this kind of battery. They are NimH AA batteries.

**broken link removed**

If they're a total of 6v when 4 batteries were connected. When will they be not functioning well on mobile robot's motors if I have two dc motors? Is it 3v which is the half of 6v? Is it the voltage or current?

 

[Diver300]

Somewhere around 1.1 V per cell and they are pretty well dead. I would say 4.5 V could be taken as the point where things will stop.

You certainly won't get much out of any motors if the battery voltage is 4.5 V. The batteries will have lost their ability to produce large currents by then.

 

[DemonicSandwich]

Nominal voltage of a NiMH cell is 1.2v. Four of them is 4.8v. About 0.9 to 1.0v is dead for a NiMH cell (3.6-4.0 for four).

 

[lloydi12345]

Thanks for the reply Diver300 and DemonicSandwich. Is it also the same with other batteries like alkaline AA?

 

[DemonicSandwich]

No, different battery chemistry's have different voltage levels.

Alkaline cells should produce 1.5-1.6v new. Most devices consider them dead around 1.1v under load.

 

[lloydi12345]

Thanks a lot for the quick replies