Drones / UAV · Tool

LiPo C-Rating & Voltage Sag Checker

Verifies whether a LiPo pack can actually sustain your drone's continuous and burst current draw. Computes voltage sag from per-cell internal resistance and warns when manufacturer C-ratings are overstated.

EndpointPOST /v1/drones-uav/lipo-c-rating-checkerVersionv1.0.0Added2026-05-25

Inputs

pack_capacity_mahRequirednumber (mAh)Pack Capacity
required · min 100 · max 50000 · default 1500
pack_cells_sRequiredenumCells (S)
required · default "4" · one of: 1, 2, 3, 4, 5, 6, 7, 8, 10, 12
Series cell count. 4S = 14.8 V nominal, 6S = 22.2 V nominal.
pack_c_continuousRequirednumber (C)Continuous C Rating
required · min 5 · max 300 · default 95
Headline rating from the pack label. Most race-pack ratings are optimistic — assume 60–80% of the printed value.
pack_c_burstnumber (C)Burst C Rating
min 5 · max 600 · default 190
Short-duration peak rating (often 2× continuous on race packs).
num_motorsRequiredenumNumber of Motors
required · default "4" · one of: 3, 4, 6, 8
motor_hover_current_aRequirednumber (A)Hover Current per Motor
required · min 0.1 · max 200 · default 2.1
Current per motor at hover throttle on this pack — from the motor manufacturer's thrust table at the hover-thrust row.
motor_max_current_aRequirednumber (A)Max Current per Motor
required · min 0.5 · max 400 · default 26
Current per motor at 100% throttle on this pack. Use the manufacturer table's max row.
cell_ir_mohmRequirednumber (mΩ)Per-Cell Internal Resistance
required · min 0.5 · max 100 · default 4
From an IR-capable charger reading (iSDT, ISDT, ToolkitRC). Healthy LiPos: 2–5 mΩ; mid-life: 5–10 mΩ; ageing: 10+ mΩ.

Outputs

pack_voltage_vnumber (V)Pack Nominal Voltage
pack_continuous_capability_anumber (A)Pack Continuous Capability
pack_burst_capability_anumber (A)Pack Burst Capability
total_hover_current_anumber (A)Total Hover Current
total_burst_current_anumber (A)Total Burst Current
continuous_headroom_pctnumber (%)Continuous Headroom
burst_headroom_pctnumber (%)Burst Headroom
voltage_sag_burst_vnumber (V)Voltage Sag at Burst
sagged_voltage_per_cell_vnumber (V/cell)Per-Cell Voltage at Burst
min_recommended_cnumber (C)Min Recommended C
verdictstringVerdict

Example request

curl -X POST https://toolsamurai.com/api/v1/drones-uav/lipo-c-rating-checker \
  -H "Authorization: Bearer sk_free_•••••••••••••••" \
  -H "Content-Type: application/json" \
  -d '{
       "pack_capacity_mah": 1500,
       "pack_cells_s": "4",
       "pack_c_continuous": 95,
       "pack_c_burst": 190,
       "num_motors": "4",
       "motor_hover_current_a": 2.1,
       "motor_max_current_a": 26,
       "cell_ir_mohm": 4
     }'

Example response

200 OK
{
  "ok": true,
  "tool": "lipo-c-rating-checker",
  "domain": "drones-uav",
  "version": "1.0.0",
  "result": {
    "pack_voltage_v": ,
    "pack_continuous_capability_a": ,
    "pack_burst_capability_a": ,
    "total_hover_current_a": ,
    "total_burst_current_a": ,
    "continuous_headroom_pct": ,
    "burst_headroom_pct": ,
    "voltage_sag_burst_v": ,
    "sagged_voltage_per_cell_v": ,
    "min_recommended_c": ,
    "verdict": "…"
  },
  "meta": { "latency_ms": , "request_id": "req_…" }
}

Tags

lipoc-ratingvoltage-sagbatterydronefpvinternal-resistance