Schematic diagram of charging a 200 amp hour battery with a PD9140 charger & charge wizard starting at 80% discharged.

See PD Data.

The PD delivers 40 amps until 13.5 volts is reached at which point the current falls as the battery voltage rises until the current is zero at about 14.4 volts.

• 20-60% takes two hours to gain 80 amp-hrs.
• 60-80% takes 1 1/3 hours to gain 40 amp-hrs.
• 80-99% takes 2 2/3 hours to gain 40 amp-hrs.
• About 6 hours to gain 160 amp-hrs starting from 80% discharge.
• About 4 hours to gain 80 amp-hrs starting from 60% discharge.

It takes twice as long to recover the second half of the charge as to recover the first half. This is because the PD's "boost mode" characteristic starts to decrease current at around 13.5 volts.

The figure is based on one published by R. Perez, see:
http://www.homepower.com/files/battvoltandsoc.pdf

DISCLAIMER: the above calculations are probably within 20% of reality.

dmartin@newarts.com 2004 may 2