Build Your Own Combat Robot

96 Build Your Own Combat Robot
FIGURE 5-7
Various NiCad
Batteries (courtesy
of Panasonic)
of the two. Generally, a charger designed for this purpose must be used. Excellent
fast chargers for NiCads are readily available.
Slow charging can be accomplished by sending a current equal to 1/10 th
of the
Ahr rating of the battery for 15 hours. It is important that you not allow the battery
to remain on this type of charger for long periods (longer than 24 to 48 hours)
or else the NiCad will suffer from voltage depression (about .1 to .2 volts per cell).
Figure 5-7 shows various NiCad batteries.
Following are the advantages of NiCad:
■ It has an excellent cost verses performance ranking.
■ For long-term use and with proper care, the NiCad can be less expensive
in the end—even less than the SLA.
■ With proper care and storage, NiCads can last through more than
1,000 charge cycles—though a chance to run this many charge cycles
is not likely to happen in the harsh world of a combat robot.
■ NiCad packs are small, so they can be stored in your refrigerator for
long periods of time.
■ The NiCad battery is moderately priced, so you can purchase more
than one battery pack.
■ The energy density is good—three times that of SLA—and in this
application surpassed only by NiMH.