I am making my first battery charger for ni-mh and ni-cd batteries that i use.

I have 9 battery slots :

1x : 9v ni-mh or ni-cd battery

4x : AA 1.2v batteries for ni-mh or ni-cd batteries

4x : AAA 1.2v batteries for ni-mh or ni-cd batteries

as from this link : Reduce voltage to many lower output with resistors and from other circuits and search around the net i understand how it needs to be done to one battery.

But how needs to be done to many as for my needs i need some help.

I havent connect them yet parallel or one by one or serial or whatever it needs. I just have a stable input from a ac to dc transformer that gives me 12volt - 2 amperes

what i want is learn how to do this, if i cant charge them all at once at least to be able to charge as much as i can with a simple way of resistors and diodes. I even have 78L05 that outputs 5v - 100/150 mah stable or mt1117 stable 3.3 volt output and 1 amp or adjustable. Ofcourse the only thing needed is a led to each battery when plugged in to indicate that is connected and charging. (ofcourse if i want the led to go off when fully charged i need some q1 transistor etc etc that i personally dont want to complicate things to much).

I need help to understand which is the best way to charge as many as possible with low mah of about 150 - 300 mah or even splitted by its types and use an appropiate mah for each type.

------------------------------------- UPDATE -------------------------------------

I am updating this post and maby someone could help i have this circuit for my 4xAAA 1.2V batteries and i need to charge them at a stable current of 150 mah - 160 mah I use the 78L05 regulator that provides 100mA stable and 5V output. More infos about 78L05 here :

Can anyone tell me if this circuit is working correct cause i dont have the appropiate test equipment for the moment and the online circuit creations are not so helpfull at my knowledge. Any kind of help or correction would be nice

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You're probably going to need a microcontroller to monitor and control the charging. NiMH and NiCd batteries require careful monitoring of the current, voltage, and maybe temperature too. This will be difficult to do with just resistors and diodes. These links say more:

http://www.powerstream.com/NiMH.htm http://batteryuniversity.com/learn/article/charging_nickel_based_batteries

  • \$\begingroup\$ Thank you for your answer and for the links, i need microcontroller cause i use different types AAA, AA and 9V or its the same if i had only 4 batteries of the same type ? \$\endgroup\$
    – Nocs
    Mar 20 '17 at 12:07

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