HRB Power Batteries 7.4 V (2S)

HRB Power 7.4 V (2S) LiPo Batteries

HRB 2S packs are a dependable choice when you want controllable speed and solid runtime without pushing your electronics too hard. They pair well with 1/10 scale RC cars and trucks, small to medium RC boats, trainer aircraft, and lightweight multirotors that are designed for 2S.

When to Choose HRB 2S

• Use if your ESC and motor are rated for 2S and you want predictable handling and cooler-running electronics.
• Use for 1/10 bashers, touring cars, short-course trucks, crawlers, and small hull boats where control and runtime matter more than top speed.
• Use for trainer planes and small multirotors that prioritize efficiency and light weight.
• Avoid if your model is geared or tuned for high voltage (3S+); consider 3S/4S only if your electronics and drivetrain are rated for it.

Picking the Right HRB 2S Pack

• Capacity (mAh): Higher mAh = longer runtime but more weight.
  • Cars/Trucks (1/10 bashing): 4000–6000 mAh
  • Crawlers/Trail: 3000–5000 mAh
  • Boats (small–medium): 4000–6000 mAh
  • Planes/Multirotors (light): 1500–3000 mAh
• C Rating: Match or exceed your peak current draw. For general driving, a realistic continuous C of 25–50C is typically sufficient; high-draw setups benefit from higher C.
• Case Type: Hardcase for off-road car protection; softcase for weight-sensitive aircraft and tight battery trays.
• Connector: Check your ESC plug (e.g., XT60, Deans T, EC5). Choose a matching pack or use a quality adapter with minimal resistance.
• Size & Fit: Verify tray dimensions. Many 2S 5000 mAh hardcase packs are about 138 × 47 × 25 mm and 270–320 g, but confirm the exact listing before purchase.

Quick Compatibility Checklist

• ESC set to LiPo mode and 2S (7.4 V) battery type.
• Low-voltage cutoff (LVC) at 3.2–3.4 V per cell (6.4–6.8 V total for 2S).
• Gearing appropriate for 2S to prevent overheating.
• Connector polarity and fit verified; no damaged leads.

Runtime Planning

Estimate runtime with a simple rule of thumb:

Runtime (minutes) ≈ (Capacity in mAh ÷ 1000) ÷ Avg Current (A) × 60

• 1/10 short-course truck, avg 30 A, 5000 mAh → ~10 minutes
• Crawler, avg 5–10 A, 5000 mAh → ~30–60 minutes
• Small boat, avg 40–60 A, 5000 mAh → ~5–7.5 minutes

Actual results vary with gearing, terrain/water conditions, and driving style.

Charging and Care

• Balance charge every time at 1C unless the pack is clearly rated for higher (e.g., 5000 mAh → 5.0 A max at 1C).
• Storage at 3.75–3.85 V per cell if not used for more than a day or two.
• Avoid resting below 3.5 V per cell; stop a run if power sags or LVC triggers.
• Let packs cool to ambient before recharging; discontinue use if swollen, punctured, or hot spots develop.
• Charge on a nonflammable surface in a LiPo-safe bag; never leave charging unattended.
• Typical full charge time at 1C is about 60–75 minutes.

Use-Case Guide

Model Type	Typical Capacity	Notes
1/10 buggy/truck (bashing)	4000–6000 mAh	Balanced speed and runtime; start with moderate C to protect drivetrain.
Crawler/trail	3000–5000 mAh	Low average current; prioritize fit and weight for better side-hill stability.
Small–medium RC boat	4000–6000 mAh	Watch temps; boats draw high current continuously—use higher C ratings.
Trainer plane/light multirotor	1500–3000 mAh	Choose softcase for weight savings; confirm CG and battery bay size.

Alternatives

• 3S (11.1 V): More speed and punch; only if your ESC/motor/drivetrain are rated for it and gearing is adjusted.
• NiMH: Safer handling and simpler charging, but heavier with lower performance vs. LiPo.

Frequently Asked Questions

What charge rate should I use?

Use 1C unless the specific HRB pack label and datasheet allow higher. Example: 5000 mAh → 5.0 A maximum at 1C.

What low-voltage cutoff should I set?

Set LVC to 3.2–3.4 V per cell (6.4–6.8 V total for 2S). Stop running if the vehicle sags or cuts out under load.

Hardcase or softcase?

Use hardcase for off-road cars/trucks to protect against impacts. Use softcase for aircraft or vehicles where weight and fit are priorities.

Will these fit my battery tray?

Check the exact dimensions and weight in the product listing against your tray. Many 2S 5000 mAh hardcase packs are ~138 × 47 × 25 mm, but sizes vary.

Which connector do I need?

Match your ESC connector (e.g., XT60, Deans T, EC5). Avoid loose adapters; if needed, use high-quality, low-resistance connectors and correct polarity.