LiPo Storage Voltage Calculator (LiPo, LiHV, LiFe, Li-ion)

How to use the calculator

Choose the chemistry printed on the pack label, then the number of cells in series — the 'S' number, such as 4S or 6S. The calculator multiplies the typical per-cell values by the cell count and shows three pack voltages: where to store it, where a full charge stops, and the resting voltage you should never go below.

Parallel cells (the 'P' in 3S2P) don't change the voltage, only the capacity, so ignore them here. If you fly two packs in series — a pair of 6S packs on a 12S heli, for example — either calculate each pack on its own or pick 12S for the combined figure.

The results are resting voltages: the reading after a pack has sat off the charger and out of the model for a few minutes. Under load the voltage sags lower, and right after charging it reads a touch higher, so compare like with like.

Why storage charge matters

Lithium cells age fastest when they sit at a high voltage, especially somewhere warm. A pack left full for weeks tends to gain internal resistance, lose punch and, eventually, puff. A pack left nearly empty has the opposite problem: self-discharge can pull a cell below its safe minimum, and some packs never recover from that.

Storage voltage is the middle ground — roughly half charge — where the chemistry is under the least stress. If you won't fly a pack within a few days, bring it to storage. It costs you a short charger cycle and buys you a lot more good flights over the pack's life.

LiHV, LiFe and Li-ion are different

Each lithium chemistry has its own voltage window, so don't use LiPo numbers for everything:

• LiHV (high-voltage LiPo): full at 4.35 V per cell, storage around 3.85 V. Charge on the LiHV setting only if the label says LiHV.
• LiFe / LiFePO4 (common for receiver and transmitter packs): full at about 3.60–3.65 V per cell, storage around 3.30 V, minimum around 2.50 V.
• Li-ion (18650 and 21700 packs for long-range builds): full at 4.20 V per cell, storage around 3.60–3.70 V, minimum roughly 2.50–3.00 V depending on the cell.

Reaching storage voltage with your charger's Storage mode

Most hobby balance chargers have a Storage (or STORE) mode. Plug in the main lead and the balance lead, set the correct chemistry and cell count, and start Storage. The charger charges a low pack up, or discharges a full pack down, to its storage target and balances the cells on the way. Discharging is slow on many chargers, so if you plan ahead, fly the pack first and store it from used.

Double-check the chemistry setting before every run. A LiPo charged on a LiHV profile is pushed past its 4.20 V limit, which is a fire risk. If your charger's storage target differs slightly from this calculator, go with your pack and charger maker's spec.