How to Make Your RC Car Faster Pt.2: Upgrading the Battery

In the previous part of our How to Make your RC Car Faster series we learned how to pick the right motor to make your RC car faster. Now that you have that monster motor your RC car will be draining your battery pretty fast. So it's about time you learned how to upgrade your RC car battery.

                                 Upgrading the Battery
    Upgrading your RC car's battery is one of the easiest, cheapest, and effective upgrades you can do. The battery as you know, supplies power for the motor, servo (steering), receiver and ESC. So by the time you finish reading this you should be able to understand all those numbers you'll see when buying a battery.

NiMH Batteries
    NiMH batteries, also known as Nickel Metal Hydride, are one of the most problem free types of batteries you can find. Pretty much the only problem with them is that they may self-discharge more than other batteries and that many of them don't hold their charge as great as other batteries. But you can find many high capacity NiMH batteries to keep your RC vehicle powered for a good long time. NiMH batteries tend not to suffer from voltage depression (also known as "memory effect"). Memory effect supposedly occurs when the battery is not fully discharged between charging cycles. Then when you have a partway full condition the battery will "remember" the shorter cycle and is reduced to a lower capacity which means less run time. For example: you use 60% of your batteries power and then charge it. The battery will then only charge to 60% of its potential. The way people keep this from happening is by completely discharging the battery before recharging. But the good thing is that NiMH batteries don't suffer from this problem!

Pros: High capacity is available, Safer than other types when overcharged, Less of an environmental problem, no memory effect problems.
Cons: not always the advertised capacity, heavier than other battery types (typically 400grams), some won't hold a charge well.

NiCd (NiCad) Batteries
    NiCad batteries (nickel cadmium) are good for beginners and cheap to buy. Sounds great, but the catch is... these batteries suffer from memory effect. They are more durable than NiMH batteries, so they can get hotter and take more abuse. Eventually NiCad batteries will be banned because of their environmental effect, so now companies have stopped developing them and are focusing more on the NiMH batteries.

Pros: Cheap, durable.
Cons: Old technology, lacks power, lacks capacity, heavy (typically 350 grams), has memory effect.

LiPo Batteries
    Lipo batteries (Lithium Polymer) are lightweight, unlike both NiMH and NiCd batteries. They don't suffer from memory effect like NiCd batteries do. They hold a better charge than other battery types. About 20-30% longer life for the same capacity as a NiMH. LiPo batteries also don't self-discharge, this means you can charge them a week before you use it and it will still have close to, if not the same amount of power. The downfalls of LiPo batteries are that if overcharged or punctured it has been known to burst into flames.

Pros: Relatively cheap, Light (typically 250grams), No memory effect, Powerful, Great capacity.
Cons: Dangerous if overcharged or punctured (may burst into flames), not recommended for beginners.

    So those are the three main types of batteries. Now we dive deeper into the meaning of all those numbers (the different ratings) you're sure to see when picking the perfect battery.

mAh (Milliamp Hours)

    Probably the biggest thing you'll see when picking a battery is the mAh rating, which stands for milliamp hours. You can think of Milliamp Hours (mAh) as how much gas a car's tank can hold. So a battery with 5000mAh will run way longer than a battery with 1200mAh. Milliamp Hours don't have anything to do with your RC car's speed just the run time.

V (Volts
    If mAh is how much fuel your car can hold then volts would be how much power that fuel can give. If you have an 11.1 volt battery (11.1v) it will give your motor more power than a 7.2v  battery can. But before you get a higher voltage battery make sure your RC motor can handle it (Just look up your motor model to find out.).

C-rating
    C-rating is a rating you'll find when looking at LiPo batteries. There are two C-ratings you'll find. One stands for max continuous discharge potential and the other for max burst discharge potential. The continuous discharge potential is how much power the battery can discharge at any given moment. The max burst discharge is the amount of power the battery can burst to. Usually the burst is only towards the beginning, when the battery is fully charged. The max discharge is always double the continuous discharge. Now that you know what the C-rating is you need to know what it means to you. Well with a higher C-rating your car, truck or buggy will have a lot more burst or acceleration when coming out of corners. A higher C battery will also keep a cooler temperature than a lower C. Higher C-rating can also improve top speed. A common misconception is that a higher C-rating will discharge faster and give you less tun time. That's not true, a higher C-rating just means your battery has more power to give at any time you wish. So all in all you should go for the highest C-rating you can get.

S (Cell Count)
    The cell count is how many separate battery cells are put together in one pack. For example: 2S1P = 2 cells in one pack, 3S1P = 3 cells in one pack. Easy. Every cell has about 3.7 volts of power, so a 3S battery would give 11.1 volts of power. This may be important if your motor or ESC says specifically.

Making Sure It Fits
    Making sure your battery fits is just as important as making sure your motor fits. You don't want to buy a battery that doesn't fit. So measure the area where your battery would go and look at the battery's dimensions to see if it will fit.

                                                                         Up Next...
    Hopefully now you understand the different ratings and numbers you'll see when buying an RC battery. If there's something you don't understand then just leave a comment and it will get answered. Up next we'll be talking about making your RC car, truck, or buggy faster with gearing.