RC Batteries
Batteries are needed in the RC world because they help make everything go. Without batteries we have nothing to power the servos and receivers.
So, what type of battery is better? NIMH or LIPO?
Both kinds are used to power electric model RC Models, but, what's the difference between them? I hear you ask?
NIMH batteries or Nickel - Metal - Hydride Batteries ( or NIMH for short - Pronounced NIM - the h is silent) are usually the included battery in an RTR (Ready To Run) RC Model. They are inexpensive and don't require special care, but they are heavy, heavier than a LIPO of similar voltage and capacity.
A NIMHs voltage decreases steadily as the battery is discharged (used), your RC slows in speed with each passing minute.
The cells used in NIMH batteries are the same as a AA or AAA battery that you power TV remotes and torches for example. NIMHs are constructed using 6 - 8 of these types of batteries (Cylindrical Cells).
LIPO Batteries or Lithium - Polymer batteries, are lighter than a NIMH with similar voltage, and this in turn helps your RC Model to feel more powerful. Helping to contribute to that feeing of more power is the LIPOs ability to hold its voltage longer as the battery is used. Instead of producing less voltage while in use, a LIPO will hold voltage longer for most of its use then drop off suddenly (stops) at the end of the battery charge.
LIPOS are more expensive than NIMHS and do require more care. They look like a flat slab type cell, and they are either 2 or 3 cell configurations.
When you are looking at batteries either NIMH or LIPO, there are a few things to think about;
1. THE CAPACITY - This determines how long your RC Model will run per charge and
2. THE VOLTAGE - This determines how fast your RC Model goes and how much power your RC Model will deliver.
Capacity
On the battery label you will see a big number like 3300, 4000, 5000, 5500 etc. This number indicates the batteries capacity in milliamp hours or "mAh" for short.
The bigger the number - the longer your RC Model will run per charge.
So, let's say your battery is rated at 5000 mAh, this means it can hold a steady 5 amps for a full hour. A milliamp is 1/1000 of an amp, if you divide the mAh x 1000 you get the amps. So, 5000 divide by 1000 = 5 amps.
Remember - The bigger the number, the longer the run time.
Voltage
The two important numbers on any battery are the capacity and the voltage. Just as with capacity, more volts are better to a certain point. Dependant on what power system your RC Model is designed for - Too much voltage could shut down your RC Model or worse - Fry the electronics, so check your speed control specifications.
A battery voltage is determined by the number of cells it has. A single NIMH cell gives off 1,2 volts and NIMH batteries generally come as 6 or 7 cell packs or by their voltage (7.2 volts and 8.4 volts).
With LIPOS it's a bit different. Same principle as a NIMH but, because a single LIPO cell gives you 3.7 volts you have fewer cells in the LIPO pack for a certain voltage. The most common LIPOS come as 2 cell (7.4 volt packs) and 3 cell (11.1 volt packs), depending on the RC Model you have and how much voltage it can handle, you might be able to use 4, 5 or 6 cell LIPOS, (it all depends on what your power system specifications are, so make sure to check your RC Models information).
So what about the "S" and what does it mean?
Just as we have talked about it before NIMH and LIPO battery packs are often referred to by the number of cells in the pack, e.g.: 2 cell or 3 cell. You may have also seen or even read about LIPO packs with a designation such as 2S, 3S, 4S etc.
The S refers to series, and shows that the cells within the battery pack are connected "Positive to Negative". Some LIPO battery packs feature cells connected both in series and in parallel, which is designated by a P, e.g.: a 2S2P LIPO battery pack would have two pairs of LIPO cells inside. Each pair would be wired in parallel (2P) and the two pairs would be wired together in series (2S), S!*T - Is your head hurting? Mine certainly is........ Now almost every RC LIPO is wired in series and referred to as 2S, 3S, 4S etc.
Cells that are connected in series have their voltage combined.
A 2S pack would have two 3.7-volt cells in series, inside the pack. The cells are connected by their Positive (+) and Negative (-) tabs to deliver 7.4 volts.
Okay, A quick bit of info on battery chargers!
First and most important!
If you have NIMH batteries you need a NIMH charger. If you have LIPO batteries you need a LIPO charger. It is so so important to get that right!!
If you use both battery types, there are chargers you can get with settings for both LIPO and NIMH. Just please make sure you have the right setting selected before pressing start.
Amperage is an important feature on chargers, the higher the chargers amp output the faster it can charge your battery pack. If you have a 4-amp charger, a 3000 mAh battery will be charged in about 45 minutes. Now you might be thinking "If more amps are better, then why not get a 10-amp charger?' Batteries do not like to be charged fast, and if you tried that amperage you would just smoke the battery.
Charging at lower amps will extend your battery life.
BE SAFE! AND PLEASE REMEMBER
When charging your battery NEVER leave it unattended!!. 99.999 Percent of the time batteries charge without a problem. But, If you are like me and fall into the 0.0001 Percent category, then staying near your battery while it is charging would be a smart thing to do.
Always use the right charger for your battery. Never use a NIMH charger with a LIPO battery because LIPOS tend to catch on Fire.
Make sure your charger has the right connectors.
A flame-retardant charging bag is a great idea when charging your batteries. It ads a layer of safety, it protects the battery and the environment during charging and lessens the chance of a Fire.
Store your batteries at 20 Percent charge, and store them in a cool, dry place.
And
Please DO NOT charge a NIMH battery on a LIPO charger!!
We hope you find this information helpful, Happy RC-ing From the Team @ Aussie Hobbies.