# Jnfkldsb 8.0Ah Compatible with DeWalt 20V Max Battery

- Manufacturer: Jnfkldsb
- Tier: C
- Price: $49.99
- Stated capacity: 8 Ah
- Amazon listing: https://www.amazon.com/dp/B0FPCPDH6V?tag=lithiumsteppe-20
- Battery page: https://www.lithiumsteppe.com/battery/jnfkldsb_8ah

## Summary

Good performance across the board mainly due to great 18650 cell use, but the electrical construction is poor and the case will melt plastic onto your tool under high-power use. Cannot recommend over more robust designs like xiuqiyu or waitley.

## Ratings

- **Honesty**: 1.7/5 — Actual capacity 3.85Ah. 8.0Ah is a complete joke.
- **Durability**: 1.1/5 (teardown 0.5/5, cycling 1.7/5) — Low-quality tool contacts risk getting melted plastic on your tool.
  - Teardown notes: Low-quality tool electrodes; risk of depositing melted plastic onto the tool's contacts after sustained use.
- **Capacity**: 3/5 — Measured capacity is 3.85Ah, less than half of the 8.0Ah claim.
- **Power**: 1/5 — Solid power delivery, but the plastic around the tool contacts will melt with extended use.
- **Safety**: 3/5 — No safety features and shoddy electric current routing.

Scoring rules: https://www.lithiumsteppe.com/methodology

## Testing statistics

- Stated capacity: 8 Ah (144 Wh @ 18 V)
- Measured capacity: 3.8 Ah (69.2 Wh @ 18 V)
- Pack internal resistance: 65.3 mOhm
- High-power cycles survived: 6
- Peak sustained power: 945 W
- Energy delivered (failure test): 37.3 Wh

## Cell notes

EVE Energy ICR18650/20P. Rated 30A max continuous discharge, 2000mAh capacity.

## Test data

Test procedures: https://www.lithiumsteppe.com/test-procedures

- **Pack Internal Resistance Test** (rinternal): Pack Resistance: 65.3 mOhm (average value of pack resistance between 17.5 and 18.5 V)
  - CSV: [rinternal.csv](tests/rinternal.csv)
  - Bench source file: jnfkldsb_8ah/rinternal_jnfkldsb_8ah_260512-16-40-21_0.csv
- **Capacity Test** (capacity): Capacity: 69.2 Wh (48% of stated 8 Ah @ 18V Nominal)
  - CSV: [capacity.csv](tests/capacity.csv)
  - Bench source file: jnfkldsb_8ah/capacity_jnfkldsb_8ah_260512-18-59-14_0.csv
- **Cycling Test** (performance): High-power cycles survived: 6. Failure mode: Battery thermistor reached cutoff
  - CSV: [performance.csv](tests/performance.csv)
  - Bench source file: jnfkldsb_8ah/performance_jnfkldsb_8ah_260518-11-28-23_0.csv
- **Failure Test** (failure): Energy discharged: 37.3 Wh, Peak power: 945 W
  - CSV: [failure.csv](tests/failure.csv)
  - Bench source file: jnfkldsb_8ah/failure_jnfkldsb_8ah_260518-12-44-28_0.csv

### CSV format

1 Hz samples. Lines starting with `#` are run metadata (test profile, battery profile, instrument identity, Arduino DAQ channel labels); the first non-`#` line is the column header. Columns vary by run date — Arduino DAQ columns (tc/v/r_ntc/fault) appear on runs logged since 2026-05-11.

- `ts_unix / ts_iso` — sample timestamp (Unix seconds / ISO-8601 local time)
- `elapsed_s` — seconds since test start
- `voltage_v` — pack voltage, V (4-wire remote sense)
- `current_a` — discharge current, A
- `active_power_w` — discharge power, W
- `discharged_ah / discharged_wh` — integrated charge / energy removed
- `phase / target / cycle` — load-profile phase name, setpoint, loop count
- `tc1_C..tc4_C` — Type-K thermocouple temperatures, Celsius (nan = channel absent, disabled, or faulted)
- `v0_V` — DeWalt C3 cell-tap voltage, V
- `v1_V` — DeWalt TH thermistor-pin voltage, V
- `r_ntc_ohms` — pack NTC thermistor resistance, ohms, derived per-tick from v1_V and pack voltage (DeWalt tool thermal cutoff reference: 2140 ohms)
- `fault1..fault4` — MAX31856 status byte per thermocouple, hex (00 = healthy)

## Photos

- Headline photo: photos/headline.png
- Teardown 1: photos/teardown_1.jpg — Visible pack deformation across enclosure after failure test
- Teardown 2: photos/teardown_2.jpg — wire-based current routing with de-soldered connections
- Teardown 3: photos/teardown_3.jpg — Cell ruptures and deformed bottom enclosure
- Teardown 4: photos/teardown_4.jpg — Cell label: ICR18650/20P 5PAD5iM005043J / 7.2Wh / 2.0Ah

## Files in this dataset

- `README.md` — this file
- `site.json` — the published data record for this battery (machine-readable)
- `tests/{rinternal,capacity,performance,failure}.csv` — raw bench CSVs (see CSV format above)
- `photos/` — headline + teardown photos (captions above)
- `test_procedures.md` — the four bench tests
- `ranking_methodology.md` — how ratings are scored

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Source: Lithium Steppe (https://www.lithiumsteppe.com) — We test DeWalt-compatible power tool batteries on Amazon to guide your purchasing decisions.
Generated: 2026-07-16T19:29:36.763Z (site commit a353b4a)
Contact: https://www.lithiumsteppe.com/contact
