Data Hacking

50 Part I — Hardware Hacks
1.5V
+ −
+ −
FIGURE 3-9: Two AA batteries
in parallel provide 1.5 volts
However, there is a side effect. The capacity of the batteries is increased. Therefore, if you take
four AAs and put them into two pairs of two in series and join the two pairs in parallel, as
shown in Figure 3-10, the output voltage would still be 3 volts, but the capacity (or how long
the batteries would last) would be doubled.
+ −
+ −
3V
+ −
+ −
FIGURE 3-10: Four AA batteries arranged to provide 3 volts
As long as you have no more than two batteries in series, you can add a few sets in parallel to
get additional power from the system. This is true no matter what kind of battery you are dealing
with (although rechargeable batteries generally run at a lower voltage — about 1.2 volts —
than alkaline batteries do).
Remember that you aren’t limited to using AA batteries. The bigger the battery, the more
power you’ll get from it!
The power order of typical alkaline batteries is as follows:
Battery Size Nominal Voltage (V) Approximate Capacity (mAh)
AAA 1.5 1100
AA 1.5 2800
C 1.5 7500
D 1.5 15000
9V 9 580