Quote:
Originally Posted by whites75
Can someone tell me a bit about batteries please. Watching stuff on youtube I keep seeing the phrase like 2's or 3's when referring to the battery. Why would you use the bigger battery, does it just make the car quicker. Also how do you know if the battery is right for a specific model of car.
Reason I ask is I am due to get a buggy and sct soon and will want extra batteries so just wanna make sure I get the right ones but also why would I choose one over the other please?
My dad has a brushed ftx carnage which one battery says 1700 nimah or something on it but the other says 3000 on it. This I am going to use as a general bashing car once I upgrade it to a brushless motor 
cheers team |
Two main types of batteries you will come across, Nickel Metal Hydride (NiMH) and Lithium Polymer (LiPO). Lipo are newer, offer much more ability to deliver lots of power quickly and have taken over all racing and most bashing.
NiMH are often packaged in ready to run kits and are fine but are an older technology. You can fully discharge a NiMH with no ill effects but you are recommended not to top up charge them, fully discharge and then fully charge - known as a cycle - from new and after storing.
LiPO must never be discharged lower than 3 volts per cell (many people don't discharge lower than 3.2 volts) or they will be ruined. However you can "top up" charge them so many people run a race, then top up the same battery ready for the next race. They must not be left full charged or discharged but in a state called "storage charge" around 3.6 volts per cell. Because a LiPO battery must not be discharged below 3 volts all modern Electronic Speed Controllers (ESC) have a built in LiPO cutoff so the car will slow dramatically when the voltage drops to 3 volts or so and will stop completely if you do not stop driving quickly. For this reason, only use LiPO batteries on an ESC that is designed to use them and has a Low Voltage Cutoff (LVC).
All batteries have a capacity measured in milliamperes per hour or mAh/hr. This is the number you have read on the batteries like 1700 mAh or 3000 mAh. These are typical values for a NiMH battery and a 1700 might just get you through a 5 min race.
LiPO's typically have much higher capacities from 5000mAh to 7000mAh which should keep you running for 20 - 30 minutes, great for bashing.
As my previous post the "S" refers to cells in (s)eries in the battery. More battery cells equals more voltage which means a faster motor speed. For racing all 10th off road is done on 2S (7.4v) and 3S is not needed or permitted AFAIK. For bashing you are free to do whatever and many use 3S to get faster motors speeds and therefore higher top speeds.
Most cars will be designed for a certain battery and can also be different shapes. Most common in NiMH are the 6 cell stick pack and rounded in shape. LiPO's are usually in a square hard case for most racing cars and are in "Stick", Shortie" or "Saddle Pack" format and your car will determine which one you should use.
You can get soft pack LiPO's but they are not allowed for racing and are more vulnerable to being punctured in a crash. This is a bad thing and can allow the pack to catch fire and the universe will end!
Hope this helps a little.