LiPo Batteries Explained: S Numbers, C Ratings, Charging, Storage & Best Practice
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LiPo Batteries Explained: S Numbers, C Ratings, Charging, Storage & Best Practice
LiPo batteries are the beating heart of modern RC cars. They’re the reason today’s trucks accelerate harder, run faster and deliver more power than anything we had in the 90s. But if you’re new to LiPos, the numbers and terminology can look confusing — and the safety advice can sound intimidating.
Don’t worry. This guide from The Truck Monster breaks everything down into simple, practical tips so you can get the most out of your batteries safely and confidently.
What Is a LiPo Battery?
A LiPo (Lithium Polymer) battery is a lightweight, high-power battery that can deliver enormous current compared to older NiMH packs. They’re the standard power source for hobby-grade RC cars because they provide:
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Higher voltage
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More punch
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Longer runtimes
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Lower weight
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Better consistency under load
If you’ve ever wondered why modern RC trucks feel so fast and alive, LiPo is the reason.
Understanding S Numbers (Voltage)
“S” stands for Series, and tells you how many internal cells a LiPo has.
Each cell is 3.7V nominal, 4.2V fully charged.
Common RC LiPo Configurations
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2S LiPo = 7.4V nominal (8.4V fully charged)
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3S LiPo = 11.1V nominal (12.6V fully charged)
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4S LiPo = 14.8V nominal (16.8V fully charged)
What it means for performance
More S = more voltage = more speed and power.
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2S = fast
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3S = wild
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4S+ = hold on tight
Always check your ESC’s rating before upgrading.
Understanding C Ratings (Discharge Capability)
The C rating tells you how much current the battery can safely deliver.
Example
A 4000mAh LiPo with a 50C rating:
4.0Ah × 50C = 200A continuous current
That’s the maximum sustained current the battery can output.
What it means for performance
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Higher C = more punch, better acceleration
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Lower C = softer throttle, more voltage sag
Manufacturers sometimes exaggerate C ratings, but as a rule:
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30–50C = suitable for beginners
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50–100C = ideal for fast brushless trucks
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100C+ = great for high-demand setups
How to Charge a LiPo Battery Safely
LiPos require proper charging — but it’s straightforward if you follow the rules.
1. Always Use a LiPo-Compatible Balance Charger
A balance charger ensures each cell is charged evenly.
Never use an old NiMH charger or a cheap unbalanced charger.
2. Charge at 1C Unless You Know What You’re Doing
1C means charging at a current equal to the battery’s capacity.
Examples:
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2000mAh → 2.0A
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4000mAh → 4.0A
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6000mAh → 6.0A
Many batteries support higher rates (2C, 3C…), but 1C is safest and extends lifespan.
3. Never Leave a Charging LiPo Unattended
This is the golden rule.
4. Use a Fireproof LiPo Bag
Cheap. Effective. Essential.
5. Stop Charging at 4.2V Per Cell
A proper charger does this automatically.
LiPo Storage — The Most Overlooked Rule
LiPos must be stored at storage voltage:
3.80V to 3.85V per cell
This dramatically extends battery life.
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Don’t store fully charged (4.2V).
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Don’t store fully flat (below 3.6V).
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Most chargers have a “Storage Mode” — use it!
Why it matters
Storing at full charge stresses the chemistry.
Storing empty risks permanent damage.
Keeping LiPos at storage voltage can double their lifespan.
LiPo Best Practices for Long Life
Here’s everything you need to know, short and simple:
Do:
✔ Charge at 1C
✔ Use a balance charger
✔ Store at 3.8V per cell
✔ Keep batteries in a LiPo-safe bag or metal box
✔ Let LiPos cool before recharging
✔ Stop using the battery if it looks puffy
✔ Set your ESC’s low-voltage cutoff properly
Don’t:
✘ Overcharge above 4.2V per cell
✘ Run the battery completely flat
✘ Leave a LiPo in a hot car
✘ Smash or crush a battery pack
✘ Charge unattended
✘ Store fully charged or fully empty
If in doubt, treat your LiPo with same respect you’d give a small petrol tank — safe and perfectly usable as long as you’re sensible.
How Long Do LiPos Last?
With good care:
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150–300 cycles is typical
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Aggressive use or fast charging reduces lifespan
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Proper storage voltage has the biggest impact
Once a battery becomes soft, puffy, or has imbalance between cells, retire it safely.
Wrapping Up: LiPos Are Incredible When Used Properly
LiPo batteries are one of the biggest reasons modern RC trucks deliver speed and performance that would have been impossible 10–20 years ago.
And the good news?
They’re easy and safe to use if you follow a few simple rules.
At The Truck Monster, all our Ready-To-Run RC trucks come with safe, appropriate charging advice — and we’re always happy to help beginners understand LiPo care.
Look after your LiPos, and they’ll look after you with massive power, long runtimes and consistent performance.