How to Charge and Store LiPo / LiHV Drone Batteries Safely
The short version: always balance-charge at 1C or below on a smart charger set to the correct chemistry, never leave a charging pack unattended, and store cells at 3.80–3.85 V per cell when they will sit idle for more than a few days. The chemistry you select on the charger must match the pack — 4.20 V/cell for LiPo, 4.35 V/cell for LiHV — because mismatching it is the fastest path to swelling, capacity loss or fire.
Charge at the correct voltage
The single most important setting is chemistry. A standard LiPo charges to 4.20 V per cell; a LiHV pack charges to 4.35 V per cell. Charging a LiHV pack on the LiPo setting under-fills it and wastes its endurance advantage. Charging a LiPo on the LiHV setting overcharges every cell and can destroy the pack or start a fire. Select the mode the pack’s label names, and double-check it before you start.
Always balance-charge
Balancing evens out the voltage across every cell, which prevents one cell from drifting high while others lag. A well-balanced pack delivers its full rated capacity and avoids the over-voltage stress that shortens life. Use the balance lead every time, not just occasionally, and let the charger finish its balancing phase rather than cutting it off early.
Use a 1C charge rate
Charge current is stated as a multiple of capacity. A 5,000 mAh pack at 1C charges at 5 A; at 2C, 10 A. Most cells are rated to accept higher rates, but 1C is the long-life default. Faster charging heats the pack and, over many cycles, accelerates capacity fade. Reserve higher rates for when you genuinely cannot wait, and never exceed the manufacturer’s printed charge rate.
Store at storage voltage
The state that damages a lithium pack most is sitting fully charged or fully discharged for weeks. For idle periods longer than a few days, bring the pack to its storage voltage and keep it there.
| Chemistry | Storage voltage per cell | Example (6S) |
|---|---|---|
| LiPo | 3.80–3.85 V | 22.8–23.1 V |
| LiHV | 3.80–3.85 V | 22.8–23.1 V |
A smart charger normally has a dedicated “storage” mode that charges or discharges the pack to the correct level automatically. Store packs in a cool, dry place — heat is the second biggest accelerant of aging after improper voltage.
Charging procedure step by step
- Inspect the pack for puffing, punctures, kinked leads or a torn balance wire; retire anything damaged.
- Place the pack in a fire-resistant container (a LiPo safety bag) on a non-flammable surface, away from anything that burns.
- Connect the balance lead and the main discharge lead to the charger.
- Select the chemistry that matches the pack (LiPo or LiHV), then set the charge current to 1C or lower.
- Start balance charge and stay within line of sight until it completes.
- Disconnect the main lead first, then the balance lead, and check that every cell rests within about 0.02 V of the others.
Safety rules that are not optional
- Never charge a pack that is hot from a recent flight; let it cool to ambient first.
- Never charge unattended or overnight while asleep.
- Never charge a puffed, swollen or physically damaged pack.
- Never charge near flammable materials, and keep a fire extinguisher rated for electrical fires nearby.
- Use a charger with a chemistry-specific LiHV setting if you fly high-voltage packs; the iMars series (mini, S100, D300) covers the balance-charging needs of the packs on this site.
When to retire a pack
Replace a battery when its capacity has visibly faded, when any cell diverges from its siblings by more than roughly 0.1 V after a balance charge, when IR readings climb sharply, or the moment it shows puffing that does not resolve at storage voltage. A pack that stays warm after charging, or that drops voltage suspiciously between flights, has reached the end of its useful life and should be discharged to zero and recycled through a battery disposal service.
Frequently asked questions
What voltage should I store a LiPo at?
3.80–3.85 V per cell. A smart charger’s “storage” mode reaches this automatically.
How fast should I charge a drone battery?
1C as a default. For a 5,000 mAh pack that is 5 A. Higher rates shorten cycle life and add heat.
Can I charge a LiHV battery on a LiPo charger?
Only if the charger has a dedicated LiHV (4.35 V/cell) mode. A LiPo-only setting under-charges the pack and wastes its capacity.
Do I have to balance-charge every time?
Yes. Balance every charge and let it complete; it is what keeps cells matched and safe over time.
How do I know a battery is bad?
Persistent puffing, a cell more than about 0.1 V off after balancing, sharp rise in internal resistance, or rapid self-discharge all signal retirement.
Can I charge a pack right after flying?
Let it cool to room temperature first. Charging a hot pack raises its already-elevated temperature and accelerates wear.