RC LiPo short runtime? Why packs die early, and what to do
If a pack dies faster than it used to, it's worn, out of balance, or the car is working it too hard. Check internal resistance, gear down a hot motor, balance-charge every time and storage-charge between sessions.
Why it happens
LiPo packs lose capacity with age and abuse. Leaving them full, running them flat and over-gearing all speed that up, and one lazy cell drags the whole pack down.
Check in this order
- Internal resistance. Most good chargers measure it. A figure climbing sharply means the pack is worn out.
- Balance. Balance-charge every time; one lazy cell limits the whole pack.
- Gearing. A hot motor is wasted runtime. Gear down if the motor is too hot to hold.
- Storage. Storage-charge between sessions rather than leaving packs full for days.
- Cut-off. Make sure the ESC cut-off is set correctly; too high ends runs early.
Parts that fix it
- 2S shorty packs: 2S Shorty LiPo
- Chargers with balance and IR measurement: Charger
- LiPo charging bags: LiPo Battery Charging Bag/Box
- Pinions for gearing down: Pinions
FAQ
How long should an RC LiPo last? It depends on use, but a pack that's storage-charged, balance-charged and not run flat lasts far longer than one that isn't.
What is LiPo storage charge? About 3.8 V per cell. Packs stored at this level age more slowly than packs left full or empty.
Why does one cell in my LiPo read lower than the others? That cell is weaker or out of balance. Balance-charge it; if it keeps drifting, the pack is wearing out.