Page 220 - Uninterruptible Power Supplies

Batteries

V
1.50

If for example the charging is done with a maximum constant voltage of 1.70 VPC, use
1.70 – 1.50 = 0.2 V in the following formula:

W = V I n where
W = Dissipated power in watt
I = Charging current in Amps

n = number of cells in series connection
V = Difference between charging voltage per cell and 1.50 V

The charging current is dependent upon how high the final voltage is allowed to go, and
on the cell type.
Figure 7.35

1.33
V

The discharge voltage is of course different for different rates of discharge and different
cell types. Use the following formula:
W = V I n where
W = Dissipated power in watt

I = Charging current in Amps
V = Difference between 1.33 V and the discharge voltage per cell
Figure 7.36

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.