Laptop power and runtime record
Yenra | Updated October 1, 2026
Article: https://yenra.com/notebook-fuel-cells/

Purpose: compare a specific laptop workload with documented fuel-cell and
battery capabilities. Follow the exact manufacturer's operating instructions.
1. Identify laptop, workload, peripherals and power system.
   Laptop/model: ____ Workload/display/radios: ____ Accessories: ____
   Module/fuel/cartridge: ____ Converter/cable: ____ Support evidence: ____
2. Record the test boundary and conditions.
   Measurement point: ____ Ambient conditions: ____ Startup time: ____
   Initial/final laptop battery charge: ____ Stopping condition: ____
3. Enter verified ratings and measured use.
   Typical load (W): ____ Sustained maximum load (W): ____
   Peak demand (W and duration): ____ Usable delivered energy (Wh): ____
   Continuous source output (W): ____ Usable battery buffer (Wh): ____
   Report/manual URL, date and page: ____
4. Calculate and interpret.
   Energy-only runtime (h) = usable delivered Wh / average load W.
   Sustained deficit (W) = load - continuous source output, when positive.
   Ideal buffer duration (h) = usable buffer Wh / sustained deficit W.
   Include source/converter losses if the energy boundary is upstream.
   Check startup, peak response, final battery state and shutdown reserve.
5. Document supported voltage/power negotiation, fuel supply, replenishment,
   total carried mass, placement and transport requirements: ____

FICTIONAL EXAMPLE: 240 Wh delivered / 30 W = 8 h; at 45 W, about 5.3 h.
If continuous output is 35 W at a 45 W load, the deficit is 10 W.
A 40 Wh usable buffer covers it for at most 4 h before other losses/limits.
These figures are invented, not specifications for the IBM/Sanyo prototype.
Historical context: the April 11, 2005 prototype claim is linked in the article.
Use current exact-model documentation for a present-day equipment decision.