Ask DH – A Primer on LiPo Batteries

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Sometimes there are questions you have about RC you’ve always wondered, but for one reason or another, never asked.  Whether you’re a seasoned veteran or brand new, we’re going to bring you up to speed. Have a question you’ve been wanting to ask? Let us know in the comments!

A great upgrade for your truck is to swap out your stock NiMH batteries for LiPo (lithium-ion polymer) batteries. They aren’t the standard cylinders you would expect, and instead come in a semi-rigid pouch.

IMPORTANT: LiPo batteries are extremely sensitive and dangerous if not handled properly. We’re not kidding. This post is meant to be helpful, but please consult your manual/local hobby shop/forums on the interwebs if you are ever in doubt. Stay safe, and stay racing.

Why switch?

Because LiPo batteries are lighter, have higher capacities and discharge rates compared to their NiMH counterparts,  they add a tremendous amount of power to your ride at the price of strict maintenance requirements and a shorter life.

Is it worth it? The 6S LiPo that we tried last night says “yes”, but that’s up to you.

The numbers explained

There are a bunch of numbers on the face of a LiPo battery. Here is a run down of what they all mean.

LipoBattery_Traxxas

 

4200 mAh (milliamp hours): This is the battery capacity which is one half of determining how long the battery will last (the other being discharge rate)

7.4v (volts): Each LiPo cell has a nominal voltage of 3.7 volts which has a direct correlation to speed. In this case If your motor is rated at 3500kV, it will spin 3500 RPM for every volt (3500 x 7.4 = 25900 RPM)

2s: How many cells the battery has (typically 2 or 3 cells). If someone is running “6s”, that means they are using two 3-cell batteries. Each cell has a voltage of 3.7v, so 7.4v total in this case.

25C: This is the discharge rate. To find the continuous discharge rate, C-Rating X Capacity (in amps). In this example, 25 x 4.2 =105A. Make sure that the motor you’re running doesn’t draw more than that on a regular basis.

Proper Care/Maintenance

  1. NEVER leave your batteries charging unattended.
  2. Always charge your batteries in a LiPo bag for safety
  3. Make sure your charger is set to the proper number of cells
  4. Never charge at more than 1C unless specifically authorized
  5. If the battery balloons or is punctured, DO NOT use it and immediately get it to a fire-safe place.
  6. Don’t let batteries drop below 3.0v. Most ESCs will have a Low Voltage Cutoff to help avoid this.
  7. Store LiPos at 3.7v (neither full charge or completely empty). Leaving a fully charged LiPo sit can cause damage.

More Info

Here is some great additional info from Traxxas on the proper care and use of LiPos.

More of a forum person? Great community post from Ultimate RC.

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