PWM Lead Acid Charging

[burgerfeet]

Hi all,

I have a concept question....is it possible or good for a secondary lead acid battery to be float (voltage) charged by maintaining the correct voltage using a microprocessor via power mosfet, or is it best to monitor current also? I have read that PWM charging a lead acid is not good but have also read that it is not an issue.

Many thanks,
Andrew

 

[RCinFLA]

Floating a lead acid at about 2.20 vdc per cell, 13.2v for six cell battery, indefinitely is fine without current sensing. However having current sensing is good to detect a cell failure that can cause a cascade failure of other cells in the string.

Over long periods, months, there can be stratification of electrolyte. A higher absorb, or equilizing charge will cause some bubbling and remix the electrolyte.

 

[crutschow]

PWM charging to improve efficiency is ok if you use an inductor at the PWM output to smooth the current pulses. Otherwise the peak current into the battery is limited only by the resistance of the PWM switch and circuitry.

 

[indulis]

Take a look at

**broken link removed**