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Single Cell Lead Acid Battery Charger

Posted by: RAJAN KS on

Dear sir,
Greetings...
We are in the process of designing a Battery charger for a Single Cell (2.1V) Lead Acid Battery with the current rating of 3 Amps maximum. The charger has to cut-off automatically once the cell is charged.
Can you please suggest us a suitable Power Integration Device for the above charger design?
Also can you please provide us a reference design or an application note for the above requirement?
Thanks
with regards,
RAJAN KS
Chief Executive
Embit Technologies,
Bengaluru
India

Comments

Submitted by PI-Sky on 02/10/2020

Hi,

Currently we have no reference designs for 2.1V but we can give guidance on how to do it.

We would need to know what is exactly meant by “charger has to cut-off automatically”. Normally Lead Acid battery chargers are float chargers which means once the voltage of the cell/battery reaches the target voltage, the charging current drops and the charger stays at the cell/battery voltage. A very weak current continues to flow and that current is just the leakage current of the battery. This enables the battery to stay charged at all times. Is the customer expecting something different that will disconnect the battery from the charger such as a relay?

Thanks

Submitted by RAJAN KS on 11/29/2021

Dear sir,

Thanks for your kind reply. Sorry I could not reply to you immediately.

Thanks for offering your guidance on how to design the 2.1V Lead Acid Battery Charger.

I mean the charger has to cut-off automatically after the battery is fully charged. We want to disconnect the charger using a relay. The relay has to be switched ON again when the battery charge drops below a set percentage (say for example 60%).   

I request to kindly guide on how to design this charger  please.

Thanks

with regards,

RAJAN KS

 

Submitted by PI-Sky on 12/08/2021

Hi Rajan,

I you were to use INN3162C which is rated for 10W, you would need a 2nd stage buck converter to convert the output voltage to ~2.1V since the minimum operating voltage for the IC is 3.3V. Currently we do not have a reference design for this but I'm willing to help you.

After that you would also need a microcontroller that would implement your charging profile. That microcontroller would also handle the turning on/off of the relay/FET that you would use to cut the connection to the battery whenever it is below 60%/at 100% respectively.

Image removed.Regards