LiPo voltage chart

Lithium polymer chemistry is unforgiving in two specific ways and indifferent to everything else. It hates being stored full and it hates being taken empty. Get those two right and packs last seasons. Get them wrong and they swell, lose capacity and eventually become a genuine fire risk. This chart is the voltage numbers behind that, per cell and per pack.

Six dollars, reads every cell

yueton

1-8S LiPo cell checker with low-voltage alarm

1-8S, per-cell readout, buzzer

A pack meter tells you the total. A cell checker tells you each cell individually, which is the only way to see the drift that means a pack is finished. A reading of 3.71, 3.72, 3.70 and 3.55 is a pack telling you to retire it, and nothing else in a normal kit will show you that.

Check price on Amazon around $6

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The charger that does storage charging properly ISDT 608AC balance charger (200W, 1-6S) $65 8A, 200W, AC and DC, XT60

Per cell state of charge

Two of those rows carry all the weight. 3.80 V is storage and 3.50 V is the floor. Everything between them is flying, and everything outside them costs you pack life.

Pack voltages by cell count

The 6S row is the one most FPV pilots need, because 6S with 1800KV motors on a 5 inch propeller is the settled default for a freestyle build. An OVONIC 6S 1300 mAh 100C LiPo (XT60) ($31) is the typical pack, and six of them is a normal field load because flights are three to five minutes.

Charging, safely and correctly

Charge at 1C unless you have a reason not to. A 1,300 mAh pack charges at 1.3 A. Faster charging is possible on packs rated for it and it shortens their life, which is a reasonable trade at a race meeting and a poor one at home.

Always balance charge. A balance lead lets the charger equalise the cells at the end of the cycle. A charger that only sees pack voltage will happily overcharge one cell while undercharging another, and that divergence is what turns a healthy pack into a swollen one.

Charge inside containment. A Zeee fireproof LiPo charging bags (2 pack) ($15) costs about fifteen dollars for two and is the cheapest insurance in the hobby. A Zeee fireproof LiPo storage box ($14) is the rigid version for packs living in a garage between sessions. Bags are for charging, boxes are for storing.

Never leave charging unattended. Lithium fires develop fast, are self-sustaining and are not extinguished by water. Charging while you are in the room is the entire safety procedure and the one people skip.

Parallel charge only matched packs. Same chemistry, same cell count and similar state of charge, on a proper board such as a XT30 and XT60 parallel charging board (2-6S) ($23). Parallel charging packs at different voltages produces a large current between them the instant they are connected, which is exactly the event you are trying to avoid.

The full routine, including which charger does what, is on LiPo battery care and storage and best LiPo chargers.

Voltage sag and why the number moves

A pack under load reads lower than the same pack at rest, because internal resistance drops voltage in proportion to current. Punch the throttle on a freestyle quad and the pack can sag a volt or more, then recover when you ease off. That is normal and it is why the floor figure is quoted under load rather than at rest.

Sag is also a diagnostic. A pack that sags noticeably more than its siblings under the same throttle has higher internal resistance, which means it is ageing, and it will reach the low voltage cutoff earlier in a flight. Ageing packs do not usually fail suddenly; they get progressively worse at holding voltage until a flight ends earlier than expected.

Cold does the same thing temporarily. Below about 10 degrees Celsius, capacity and voltage under load both drop noticeably, which is why cold-weather flights end early and why warming packs before flight is worth the trouble. See flying in cold weather.

Intelligent flight packs are different, but not exempt

The packs in camera drones contain a battery management system that handles balancing, reports state of charge as a percentage, and self-discharges toward a storage level after a set idle period. That automation is genuinely good and it is why drone owners can get away with treating packs carelessly in a way FPV pilots cannot.

Underneath it is the same chemistry with the same rules. Leaving intelligent packs at full charge for weeks still ages them, deep discharge still damages them, cold still costs capacity, and a swollen pack is still finished. The advantage is that the aircraft warns you; the obligation to act on the warning is unchanged. Specifications and carriage limits are on the battery spec chart.

Retiring and disposing of packs

Retire a pack when it swells, when a cell sits persistently below its neighbours after a balance charge, when it will no longer reach full charge, or when sag under load ends flights noticeably early. Packs are consumables and a retired pack is a successful pack, not a failure.

Dispose of them through a battery recycling point rather than household waste. Discharge safely first following the manufacturer's guidance, and never puncture, cut open or incinerate a cell. A pack that has been damaged in a crash should be isolated in a fireproof container and watched for a period before it goes anywhere near a bin, because delayed thermal events after impact damage are a documented failure mode.

Everything here is researched from published battery specifications and manufacturer guidance rather than hands-on testing, and it is general information rather than professional advice. Follow your specific pack and charger manufacturer's instructions where they differ.