lead acid battery charge current

[darla1]

dear all

i am charging lead acid battery using full bridge topology, when i check the output current with resistive load (8A) the waveform is good i.e it is in continues and having ripple current of 2A pk-pk.

next i connected the battery, the current waveform is good upto 3 amps, beyond 3 amps the output current is going to pk pk 16A. the waveform is not good it is going to 1amp to 16 amp.

i did not understand why the system is behaing like this.

can any body explain this problem.

thanks and regards
ramesh

 

[ravimarcus]

The battery is like a huge capacitor. Your charger is not able to supply the required current. Hence the huge ripple. Try putting some large capacitors across the charger.

Cheers

Ravi

 

[darla1]

The battery is like a huge capacitor. Your charger is not able to supply the required current. Hence the huge ripple. Try putting some large capacitors across the charger.

thanks Mr ravi

i am using two capacitors in parallel having each 4700uf, i hope this much capacitance is sufficient....

do you think that i need to increase further..

thanks
ramesh

 

[ravimarcus]

do you think that i need to increase further..

You will have to ask the charger :-D.

i am using two capacitors in parallel having each 4700uf, i hope this much capacitance is sufficient

Check the ripple on an oscilloscope and not with a multimeter. Increase it if necessary. Instead of using 1 large value like 10,000 uF, use small values in parallel. This will further reduce the ESR (Effective Series Resistance) of the capacitors.

Cheers

Ravi

 

[darla1]

Check the ripple on an oscilloscope and not with a multimeter. Increase it if necessary. Instead of using 1 large value like 10,000 uF, use small values in parallel. This will further reduce the ESR (Effective Series Resistance) of the capacitors.

dear ravi

i have checked the wave form with CRO only please have look on my waveform and suggest something...

thanks

ravi

 

[ravimarcus]

i have checked the wave form with CRO only please have look on my waveform and suggest something...

The waveform is from a current probe. What is the voltage ripple? If it is 1 or 2 volts / current, it should be ok I presume. To make it smooth, you will need lots of capacitors and it will cost a lot.

Cheers

Ravi

 

[darla1]

To make it smooth, you will need lots of capacitors and it will cost a lot.

dear Mr Ravi

as per my design i need to get dc output current with pk-pk of 2A, but here i am not getting dc, getting ripple dc from 1 A to 16A, this is not desirable.

if we charge the battry like this the battery life effects.....

thanks
ramesh

 

[ravimarcus]

If you are talking of pk-pk, then it is AC, what is the DC component on the output?
If you are in Bangalore, you can call me. I need to have more info about the problems you are having.

Cheers

Ravi

 

[darla1]

If you are talking of pk-pk, then it is AC, what is the DC component on the output?

dear ravi

my dc component is showing only 1A and mean value is 5A then pk-pk is alomost 16A.

i am from hyderabad

thanks
ramesh

 

[ravimarcus]

I am going offline on this topic. I have sent you my contact details. Please email me.

Cheers

Ravi

 

[BABESH]

what i understand is that to charge battery first u ned a DC voltage,
what is charging current for battery?
If it is <1.5A then use a LM317 and configure it as current source then u r current thru battery will be constant.

What is current capability of bridge rectifier.

Hope my understanding is correct...