At what mah do rechargeables become discharged

[smgtech]

I am using a MH-C9000 and it shows on the screen dischg and it is at 1400 something mah but many minutes before it was dischg and it was at 500 something mah. Any way I thought if you dischg the battery that if it were full it should start close to 2650 mah since that is what the battery capacity is and then end up at the end of the dischg at somewhere close to 0 mah but it appears the mah is going up during the discharge. How does the charger know when the battery has been fully discharged or is there a certain mah that it stops discharging at? I am refreshing and analyzing my batteries.

 

[smgtech]

discharge

At what mah does a rechargeable battery become discharged in a MH-C9000? When my MH-C9000 dischg a battery, the mah seems to be rising???

Thanks,
Steven.

 

[SilverFox]

Hello Steven,

Welcome to CPF.

Your terminology is a little bit off...

The capacity of a battery is given in mAh. This is the product of discharging at a given current (mA) for a period of time (h).

This means that if you discharge a cell at 500 mA for a period of 1 hour, it had 500 mAh of capacity.

Since the charger is able to charge many different capacity cells, it starts at 0 and works its way up.

A cell is considered completely discharged when its voltage drops to 0.9 volts. By monitoring the voltage of the cell, the charger stops discharging when the voltage drops below 0.9 volts.

Tom

 

[smgtech]

Thank you now I understand how and when it stops discharging. But I still do not understand why it goes up in mah on the MH-C9000. When it starts out somewhere at 500 mah and then at the end of the discharge it says 2300 mah does that mean that 2300 mah of capacity is available to charge? I do know that mah stands for milliamps per hour.

 

[Benson]

Thank you now I understand how and when it stops discharging. But I still do not understand why it goes up in mah on the MH-C9000. When it starts out somewhere at 500 mah and then at the end of the discharge it says 2300 mah does that mean that 2300 mah of capacity is available to charge? I do know that mah stands for milliamps per hour.

It's counting the discharge as it is performed. If it says 2300 at the end, that means it discharged the battery 2300mAh before it hit the voltage threshold -- if that was started with the battery fully charged, then it would take about that to fully charge it again, but if that discharge was started from half-empty, then it would take more to fully charge it. The charger can't know the battery's history, it just tells you what it has done.

And mAh does not stand for mA/h, it's mA*h.

 

[smgtech]

Wow I am learning a lot I thought I knew! :thanks: