Sunlayer - Robotic Lawn Mower Off Grid Solution

Off grid on ground storage and PV solution

🔢 Step-by-Step Calculation and estimation of potential products for your Robotic lawnmower. nb Does not include any storage and other requirements. Subject to final site visit.

⚙️ Step 1: Energy Requirement

Robotic Mower Specs:

- Power draw while charging: 165W
- Charging duration: 120 mins = 2 hours
- ➤ Energy per charge = 165W × 2h = 330 Wh

Assume 1 full charge per day:

- Daily energy need = 330 Wh (0.33 kWh)

Add 30% buffer for system inefficiencies and cloudy days:

- ➤ Adjusted daily demand ≈ 0.43 kWh/day

☀️ Step 2: PV Panel Sizing (Suntech 465W)

Assume 4 peak sun hours/day (NZ average):

- Daily production per panel = 465W × 4h = ~1.86 kWh/day

➤ Panels needed = 0.43 ÷ 1.86 ≈ 0.23 panels

✅ 1 panel is enough, but for year-round reliability, go with:

- ⚡ 1–2 × Suntech 465W panels

🔋 Step 3: Battery Sizing (BYD)

You want to store at least 1 full charge, ideally 2 for autonomy:

- 1 charge = 330 Wh (0.33 kWh)
- 2× = 660 Wh (0.66 kWh)
- With DoD buffer: minimum battery capacity = ~0.8–1.0 kWh usable

BYD’s smallest module:

- BYD HVS 2.56 kWh — more than enough
- Or go with BYD LVS 4.0 or stackable units if future expansion is possible

✅ Recommended:

- 1 × BYD HVS 2.56 kWh battery

🔌 Step 4: Inverter (GoodWe)

You need a hybrid inverter with battery solar input.

✅ Recommended inverter:

- GoodWe GW2500-EH (2.5kW Hybrid)
- Or GoodWe GW3048-EM (3kW Hybrid for system expansion)

🧩 Final Recommended Setup

Component

Model/Specs

Solar Panels

1 - 2 Suntech 465W

Battery

BYD HVS 2.56 kWh lithium battery

Inverter

GoodWe GW2500-EH hybrid inverter

Daily Usage ~0.33–0.43 kWh/day (1 mower charge)

Charge Time

2 hours per full cycle