Rectifier Sizing Calculator (N+1)
How many rectifier modules does the site need?
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Rectifier Sizing Calculator (N+1) by TheCalcTools
How the Rectifier Sizing Calculator (N+1) works
Enter the site DC load current and the battery bank size.
The rectifiers must supply the load plus the battery charge current; add a growth margin.
Divide by the module rating, round up for N, then add redundant modules.
The formula
Worked example
Using the default values shown in the calculator:
| DC load current (A) | 60 |
|---|---|
| Battery bank (Ah) | 400 |
| Battery charge current (C-rate, e.g. 0.1) | 0.1 |
| Rectifier module rating (A) | 50 |
| Growth margin (%) | 20 % |
| Redundant modules | 1 |
- Required current = 60 × 1.2 + 400 × 0.1 = 112.0 A.
- Modules: 3 for the load, 4 with redundancy, giving 200 A installed (10.8 kW).
Result:
| Required DC current (A) | 112.0 |
|---|---|
| Modules for the load (N) | 3 |
| Modules with redundancy | 4 |
| Installed capacity (A) | 200 |
| Installed power at 54 V (kW) | 10.8 |
Frequently asked questions
What does N+1 mean?
N modules supply the load and one extra module covers a single module failure without losing capacity.
Why 54 V for power?
A 48 V telecom system floats at about 53.5–54.5 V, so output power is current × float voltage.
Sources and further reading
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This calculator gives estimates for planning only. Electrical installations must be designed, checked and carried out by qualified personnel following local codes and the equipment manufacturer's data. Never rely on this result alone for safety-critical decisions. See our disclaimer.