Expert Advice - Batteries
Many people might not think so, but batteries play an important role in the performance of a Mini 4wd.
A good motor needs good batteries to run, or else the motor won't do well. Of course, the batteries I'm
talking about are rechargeable AA batteries. To begin talking about batteries, let's first talk about the
features of every battery.
First, you'll notice that on almost every pair of rechargeable batteries, there is a number written, followed
by the letters mAh. A pair of Tamiya Ni-Cd Mini 4wd Batteries has 1000 mAh. That's milliampere/hour, or the capacity
of electricity for the battery. The higher the number, the more space the battery has, but the weight increases as
Then you'll see the voltage. For example, 1.2 V printed on the battery.
And here's something you probably won't see on a battery: the internal resistance. Almost every conductor
of electricity has some sort of resistance to the electricity. This is where electricity is lost. This is measured
in milliohms for a battery. The higher the resistance, the less the electric flow, and therefore less electricity
flowing from your batteries to your motor.
Now that we know the basic of batteries, let's look at the types of batteries.
Nickel Cadmium batteries are better known as Ni-Cd batteries. They are overall good and common rechargeable
batteries, except that they have the memory problem. Before you recharge it, you must fully discharge it, or
when you charge it up again, it loses a bit of it's capacity. It is very noticible, and shouldn't be tried. That's
why you must always discharge your Ni-Cd batteries completely before you recharge them.
Nickel Metal Hydride
These are also known as Ni-MH batteries. Most people believe that these batteries have no memory effect,
but in reality, they do. The memory effect is not as noticeable, though. I would prefer these batteries than
the Ni-Cds simply because of the difference in memory effects.
So, is that all? There are many more types of batteries (Alkaline and Lithium Ion, just to name two), except
those aren't commonly used for Mini 4wd, and to tell you all the truth, I don't know much about them. To end the discussion
about batteries, let's talk about discharging.
Discharging Your Battery
Discharging your battery is a very important thing to do before charging it, especially with Ni-Cd batteries.
Discharging a battery takes knowledge too. When you discharge a battery, you want it to go all the way down
to 0 V. Suppose you take a flashlight or a motor to drain a pair of batteries, which, by the way, is encouraged by'
many people. At a certain voltage, the flashlight will not light up anymore. However, the battery is still being drained,
therefore damaging the cell. A motor is also the case. Down to a certain voltage, the motor simply can't spin. In other
words, using a flashlight, motor, or any other similar equipment to discharge batteries pretty stupid.
So how do you discharge batteries properly? Use a discharger! You can buy Tamiya's Mini 4wd Discharger or any other
discharger. Just make sure you don't use a flashlight or motor.
Right after you recharge a battery, it starts to lose its electricity almost immediately. Of course, this
is a very slow process. My suggestion to you is you should recharge your batteries right before a race with
a quick charger, so that your battery will have enough electricity.
If you won't be using your batteries for a long period of time, you need to know how to store them. For Ni-Cd batteries,
drain the batteries completely. For Ni-MH batteries, make sure that you have some electricity inside the batteries before
Everytime you charge and discharge a battery, you lose some of its capacity permanently. And everytime
you do so, the internal resistance builds up a tiny bit (this happens over a long period of time). In
other words, as batteries get older, they start losing their original power. So if you ever want to race
in a big-time race, you should buy new batteries, so that the power is full, and the internal resistance is the
lowest it can be.
That's all that I know about batteries. There is definitely a lot more to batteries that I don't understand, but I'm
providing the most basic information. If you see something wrong, please contact me.