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batteries along with the requisite charger to
keep them powered up. If your project uses
batteries, they will need to be monitored,
which takes some additional time and effort.
• NiMH - These are the most widely
used batteries in the construction of robots.
They offer good value with a high energy
density and very little memory effect,
making them a very popular choice.
• LiPo - It is easy to see why this design
is quickly gaining in popularity. They are
lightweight and have good capacity. They
also offer high discharge rates. The voltages
are a bit funky as they come in increments of 3. 7 volts.
• Li-Ion - The fact that these batteries have no
memory effect issues makes recharging a breeze. They have
a good power output rate and are lightweight, but are
expensive and heat sensitive. If they are completely
discharged, they are toast and will need to be replaced. Li-ion batteries do pose a higher fire danger than other
battery types, so some added care should be taken when
• NiCd - NiCds are declining in popularity as they have
a significant drawback. Improper use and charging can
cause a major memory effect. Continual recharging reduces
the capacity of the batteries. They should be fully
discharged prior to recharging in order to get the most out
• Alkaline - We have all had experience using these in
a flashlight, toy, or other device. They are low cost but non-rechargeable, so you are required to constantly buy
replacements. The convenience of being readily available
virtually everywhere is a plus.
• Lead Acid - These are inexpensive considering their
high capacity, but they are big and heavy. You need to be
sure to keep them charged, and they lack the high
discharge rates of other battery choices. Motorcycle
batteries are a good option to consider if you are interested
in giving them a try.
I have also utilized a 12V 6,000 mAh li-ion battery that
includes a wall plug charger in some of my projects (Figure
6). It comes in very handy, and is a versatile all-in-one
solution to fit many of my power needs (see Resources).
Once you decide on a battery type, you then need to
consider what capacity you need. There are many choices
available, so consider your choice carefully. I am of the
belief that more is better here, so I choose the largest
capacity possible while still considering my space and
Putting a Charge into Your
It does come with its own challenges. Keeping batteries
charged and ready when you need them is an ongoing
concern. This is where a quality battery charger can be
worth its weight in gold. Well, maybe not gold, but you get
As my battery supported projects have gotten more
complex, I have had to continually increase my reliance on a
greater number of batteries in ever-increasing capacities.
This need for more power has also demanded that I
upgrade my charging capabilities. I have had several
different models as my needs have changed. Both of my
previous chargers are models from Hitec and have served
me admirably (Figure 7). However, I once again found
myself in the market for an upgraded model.
The New Hitec X4 AC Pro Charger
I was fortunate enough to get my hands on one of the
new Hitec X4 Pro battery chargers (see Resources), so this
Figure 6. All-in-one 12V battery.
Figure 7. Pick the size you need.