Charging Algorithm for NiCd battery?

[tom12sg]

best charging method for nicd

Hi,

Anyone has any good way of charging NiCd or NiMH battery?
Are their charging method difference?
Is there any formula to calculate on how much and time to charge?
I think of using a ADC port to measure the amount of voltage left and it determine how long my charging cycle shoild be.
Any spec. or link of the above information please share.

Thanks.

 

[C-Man]

Might not exactly be what you are looking for but you should be able to get some ideas from it:

http://www.atmel.com/dyn/resources/prod_documents/doc1659.pdf

best regards

 

[Jaannee]

Hi!
The normal way of charging NiCd or NiMH is by measuring the voltage drop that happens when the battery is fully charged. Both types of batteries is charged with constant current.
The drop for NiCd is larger than for NiMH.
If you want to charge fast, you normally choose a charging current of 1C where C is the capacity of the battery. But it is a good idea to supervise the temperature of the battery when doing so.
After fast charging you can switch to trickle charge (0.01C) to keep the battery fully charged even if left in the charger.

/Janne

 

[Rayengine]

Normally we adopted same charging scheme for both NiCd and NiMH battery. Jaannee's message is quite clear. Just one more addition is the battery temperature should not rise higher than the specification which will cause degradation of batteries. Usually, it is about 45 degree C.

 

[alphi]

pls ref:

 

[jzo777n]

A good source of information is data sheets/app notes from manufactors that makes charge IC like TI, Maxim, Linear...
Or battery manufactors like Panasonic, GP..

 

[nex]

Hi,

I think that best charging method is reflex charging. You have a charge pulse (~900ms) at 1C or more, then few uS discharge at 3-4 C. After 10ms test to see if full charge. For more details I have a pdf file...

Cheers !