Radio Remi guidesSee the relationship before changing it
The figure reads from left to right. The blue card is monthly self-discharge. The middle card applies this page's rule. The green card is equivalent leak current. Walk the arrows once: set the input, apply the rule, then read the result with its unit.
The retained audit below checks several chapter fixtures. This model keeps those stated values fixed and changes only monthly self-discharge, so the numeric fixture does not switch without explanation.
Derive the baseline in four named moves
- 1
Name the input. The chapter baseline is 2 %/month.
- 2
Name the relationship. leak = 1,000 mAh x monthly percent / 720 h
- 3
Substitute with units. 1,000 x 0.02 / 720 = 27.8 uA
- 4
Read the result. Keep the unit beside the value. Use it only inside the technical boundary on this page.
Predict, then change monthly self-discharge
Try Predict the direction of leak = 1,000 mAh x monthly percent / 720 h. Test another monthly self-discharge, then compare equivalent leak current.
Observe The fixed cell leak can rival a low-duty Bluetooth profile current. Reset monthly self-discharge to 2 and compare equivalent leak current.
Explain The fixed cell leak can rival a low-duty Bluetooth profile current.
Check yourself
What should you do before trusting a moved-control result?
What does this small model leave out?
1. A fixed leak belongs in the denominator
A profile’s daily charge comes from its radio states. Self-discharge is different: it runs whether the radio is busy or asleep. Convert the monthly fraction to charge per day, then add it to each profile’s daily draw.
2. Name every algebra move
Convert the fractionQleak/day=C0 fmonth/30.
Add the daily drainsQtotal/day=Qprofile/day+Qleak/day.
Divide capacitylife=C0/Qtotal/day.
3. One leak, two relative effects
The numerator is identical for both profiles. Dividing it by BLE’s smaller profile draw makes its relative share larger, even though BLE’s corrected life remains much longer.
4. Try one controlled change
TryChange only the cell’s monthly self-discharge; both profile duty-cycle ledgers stay fixed.
ObserveAt 2%, the 0.667 mAh/day leak is 0.208% of SPP draw but 3.12% of BLE draw. Corrected lives are about 3.119 and 45.4 days.
ExplainA fixed tax is most visible when the designed load is small. The correction lowers BLE’s advantage from 15.0× to about 14.6× without reversing the decision.
The 2% per month self-discharge rate is catalog-typical.
- Chemistry and age
- Change the storage loss
- Temperature and state
- Change both leakage and capacity
- Pulse load and cutoff
- Change the usable charge
Measure the selected cell and electronics across the intended storage and load profile.
5. Reproduce the chapter values
For the chapter’s 1000 mAh cell at 2%/month, Qleak/day=1000×0.02/30=0.667 mAh/day and Ileak=0.667/24=0.0278 mA=27.8 µA. SPP life is 1000/(320+0.667)=3.119 days. BLE life is 1000/(21.36+0.667)=45.4 days, 1.4 days or about 3.0% below its 46.8-day charge-only result. The corrected ratio is about 14.6×.
6. Carry the evidence forward
Record chemistry, lot, age, storage and operating temperature, measured quiescent current, profile state timing, reconnect costs, capacity test, cutoff, and uncertainty beside the life claim.
7. Check yourself
Why is the leak not 2% of each profile draw?
Why does BLE lose more days?
Does the correction erase BLE’s advantage?
The comparison isolates profile current and one stated self-discharge rate.
- 1,000 mAh
- Illustrative nominal capacity
- 2% per month
- Illustrative storage loss
- SPP and BLE life
- Idealized current-only results
The ratio is useful for reasoning, not a warranty of field life.