9v charger 5.5 output only

[sammovde]

I have two overnight slow chargers which can charge AA, AAA and 9v batteries. I measured from a multimeter and find out the charging voltage of AA and AAA is around 1.4 - 1.5v, but only 5.5v on charging 9v batteries.

I wonder if 5.5v could fully charge the 9v batteries. Isn't 9v battery consists 6-7 AAAA-size cells conected in serial?

Any one have the same experience in charging 9v batteries and would you please tell me the charging voltage of your 9v charger?

Thanks in advance.

P.S. the batteries are Ni-MH

 

[EvilLithiumMan]

Those voltages are low. Are you measuring the voltage while the batteries are charging? If not, try to anyway. Inexpensive chargers may use half or full wave rectification without any filtering. If that is the case and you are not using a TRMS (True Root Mean Squared) meter, you will get an inaccurate measurement.

BTW, you'll get more response to your query by posting in the "Flashlght Electronics - Batteries Included" forum.

 

[mdocod]

The circuit might not "kick on" until a battery is installed. The 5.5V open circuit reading might not have anything to do with the actual charging voltage. Or as mentioned, your meter may not be able to read what the true RMS voltage is correctly.

The slots on a "smart" charger often don't read any voltage at all open circuit. (that is the case with my old vanson speedy box). The 9V slots on my vanson read almost 15V open circuit. Those slots I know are not "smart" charge slots, but rather, very slow trickle charging slots. I believe they just have the power supply directly connected to those slots with a high value resistor in line to slow it down.

Eric