STEP 1

Daily Load Assessment

List every appliance and its daily runtime. This daily Wh total feeds all downstream calculations automatically.

Appliance Load Builder

Appliance
Watts (W)
Hours/Day
Qty
Wh/Day

Total Daily Load

5,050 Wh

= kWh

5.05 kWh

STEP 2 & 3

System Architect

Configure your LiFePO4 battery bank and solar array. Indian standard peak sun hours: 4–5h (default 4.5h).

Battery Bank Configuration (LiFePO4)

LiFePO4 standard: 3.2V

↑ Voltage: S × 3.2V

↑ Capacity: P × Ah

System Voltage

51.2V

S × Cell Volts

Total Capacity

100 Ah

P × Cell Ah

Total Energy

5.12 kWh

5,120 Wh

Total Cells

16

S × P cells

Usable Energy @ 80% DoD

4.10 kWh

Solar Array & Autonomy Sizing

From Load Builder above, or enter manually

Typically 2–3 days in India

≤80% → 4,000+ cycles

India average: 4–5 hrs/day

Inverter + wiring losses ~85%

Minimum Solar Array

1,122 W

= Daily Wh ÷ (PSH × Efficiency)

Example Panels

—

Required Battery Capacity

526 Ah

= (Daily Wh × Days) ÷ (Vsys × DoD)

In kWh

—

Recommended MPPT Inverter Size

—

Handle peak load; match battery voltage (24V/48V/72V/96V)

STEP 4

Charge / Discharge Time Calculator

Enter a load to calculate exactly how long your configured battery bank will last, and how long solar will take to recharge it. Mirrors the MicroPowerGrids calculator.

🔋 Discharge Time

Battery "C" Rating

—

Load(A) ÷ Capacity(Ah). Keep < 1C for longevity.

Draw Current

—

Run Time (100% DoD)

—

Hours : Minutes

Run Time @ DoD

—

@ 80% DoD

Discharge Formula:

Time (h) = Capacity (Ah) × DoD ÷ Load (A)
Time (h) = Energy (Wh) × DoD ÷ Load (W)
Capacity(Ah) ÷ Current(A) = Hours at 100% DoD

☀️ Solar Charge Time

Charge Current

—

Charge C-Rate

—

Ideal: 0.5C max

Full Charge Time

—

0 → 100%

Charge from DoD

—

From 80% DoD

Charge Formula:

Charge(A) = Solar(W) × Eff ÷ Battery Voltage(V)
Time(h) = Capacity(Ah) ÷ Charge Current(A)
e.g. 2000Ah × 48V ÷ 1000W = 12h (with 20% loss)
Live Engine

Dynamic Stress Test

Adjust load to see voltage and SOC respond in real-time.

Simulated Load 800W
State of Charge 100.0%

SOC

100.0%

Time Left

6.4h

Energy Left

5,120 Wh

C-Rate

0.16C

Voltage Stability Monitor (ECG Mode)

SOC %
Load W
REFERENCE

Typical Indian Home Configurations

Pre-sized MPPT Solar Hybrid systems for 3 kW, 5 kW, and 10 kW homes. Values are indicative — use the designer above for exact sizing.

Best for 2–3 BHK

3 kW Home

MPPT Solar System

House Load ~3 kW connected
MPPT Inverter 3–4 kVA (24V/48V)
Battery (LiFePO₄) 48V 100Ah = 4.8 kWh
Backup @ 80% DoD 2–3 hours
Solar Panels ~3 kW array
Example Array 440W × 7 panels
💡 2–3 BHK: Lights, fans, TV, fridge, small pump
Ideal 3–4 BHK

5 kW Home

MPPT Hybrid System

House Load ~5 kW connected
MPPT Inverter 5 kVA (48V/72V)
Battery (LiFePO₄) 72V 100–150Ah
Energy 7.2–10.8 kWh
Solar Panels ~5 kW array
Example Array 440W × 12 panels
💡 3–4 BHK: mixer, washing machine, 1 ton AC, pump
Larger Homes / Villas

10 kW Home

Premium MPPT System

House Load ~10 kW connected
MPPT Inverter 7.5–10 kVA (96V/120V)
Battery (LiFePO₄) 96V 200Ah ≈ 19 kWh
Or Modular LiFePO₄ cabinet
Solar Panels ~10 kW array
Example Array 440W × 24 panels
💡 Villa: 1.5 ton AC, bigger pumps, heavy appliances

⚡ Example Higher-Load Configurations

1 Ton AC / 1 HP Motor (~5 kW system)

5 kVA MPPT Hybrid Inverter · 48V 100Ah LiFePO4 · 450W × 8 panels

1.5 Ton AC / 1.5 HP Motor (~7–10 kW system)

10 kVA MPPT Inverter · 96V 100Ah LiFePO4 · 450W × 12 panels

Off-Grid Engineering Principles

A 6-step masterclass based on Indian off-grid standards and MicroPowerGrids methodology.

STEP 1

Assess Your Load

List every appliance: Watts × Hours/Day × Quantity = Daily Wh. Example for a small Indian home:

Refrigerator: 150W × 24h = 3,600 Wh
LED Lights: 10W × 4h × 10 = 400 Wh
TV: 100W × 3h = 300 Wh
Laptop: 50W × 5h = 250 Wh
Water Pump: 1000W × 0.5h = 500 Wh
Total: 5,050 Wh/day
STEP 2

Battery Autonomy

Autonomy = days without solar (rainy days). Indian standard: 2 days.

Ah = (Daily Wh × Days) ÷ (System V × DoD)

⚠️ Never use 100% DoD on LiFePO4 — it dramatically reduces cycle life. Target 80% DoD → 4,000+ cycles. 100% DoD → ~500 cycles.

STEP 3

Choose MPPT Inverter

Your MPPT inverter must handle:

  • → Peak load in kW (sum of simultaneous appliances)
  • → Battery voltage (24V / 48V / 72V / 96V)
  • → Solar Voc and Isc within MPPT range

For a ~3 kW load, a 3 kVA 48V hybrid MPPT inverter is standard. Size slightly above your peak load.

STEP 4

The 4.5-Hour Solar Rule

Solar panels don't produce peak power all day. India uses 4–5 Peak Sun Hours (PSH). Always account for system efficiency (~85%).

Array (W) = Daily Wh ÷ (PSH × Efficiency)

e.g. 5,050 Wh ÷ (4.5h × 0.85) = 1,320 W array

STEP 5

Series vs Parallel Wiring

Series (S): + to −. Increases Voltage.

16S × 3.2V = 51.2V system

Parallel (P): + to +. Increases Amp-hours.

2P × 100Ah = 200Ah capacity

Total Cells = S × P. Total Energy = (S × V) × (P × Ah)

STEP 6

C-Rating & Formulas

C-Rate measures how fast you charge/discharge relative to capacity.

C-Rate = Load(A) ÷ Capacity(Ah)
Wh ÷ V = Ah (conversion)
Ah ÷ Load(A) = Hours (discharge)
Ah × V ÷ Load(W) = Hours
1C = full discharge in 1h
0.5C = full discharge in 2h

LiFePO4 can handle up to 1C continuous; keep charge rate ≤ 0.5C for longevity.