Need resources on how to design Ni-MH charger

[wisepie]

ds2714 current source

I need some sources/information on how to design a smart Ni-MH cell charger... what is delta-V or delta-V cut off detection..sorry, It is quite new for me to design this charger...
Pls email to me at dnamarketing(at)yahoo.com if you can help me. Thank you..

 

[Nitin Nalinde]

Ni-MH charger

Hi wisepie,

To design a smart cell charger(Ni-MH ,etc), go for Linear Technologies. They are so many solutions(ICs) for cell charger.

Regards,
Nitin.

 

[khouly]

Re: Ni-MH charger

a fast notes about Ni-MH charging

1) begin the charing with trickle this means u charge the battery with constant current equal about 50 mA , just to sense is this battery build up voltage or no

2) after that u verified that ur battery is ok , and if the temp of the battery is ok "need thermistor"

3) begin Fast Charge "with constant current " about .5 C to 1 C , this means u will done about 2 to 1 hour

4) after that Charger termination

deltaV this means that in the end of charging the voltage begin to decrease so if u detect the decrease about .02 /cell then cuttoff the fast charge mode

aslso there is another termination technique called delta T , when u dtectet that the Temp raised by 1 to 2 C degres , cuttoff the fast charge mode

Khouly

 

[wisepie]

Re: Ni-MH charger

Thank you for the information. I still have some doubts.. How about charging a battery still has half of its capacity compared to a fully discharged one.

Hi Khouly, do you have more details explanation about the delta V and delta T technique?

 

[khouly]

Re: Ni-MH charger

check these links

**broken link removed**
**broken link removed**
https://ww1.microchip.com/downloads/en/DeviceDoc/51648a.pdf
www.atmel.com/dyn/resources/prod_documents/doc1659.pdf

khouly

 

[baniliu]

Ni-MH charger

but how do we control for examle 50mA constant current, series resistor, outside or inside chip?

 

[khouly]

Re: Ni-MH charger

use constant current source , and a On of transistor switch ,cotrol the period then u get the current u want

check the datasheet of LM317 regulator to see how to use it as a constant current source

khouly

 

[satya_vijayawada]

Re: Ni-MH charger

try this link