Design

Wiring Batteries

Components

• 2 × 100 Ah batteries (100 A max output each)

• 1 × 280 Ah battery, BMS-limited to 100 A

• Total battery bank capacity: 400 Ah

• Max combined current: ≈300 A

• Inverter: 3000 W (≈250–280 A draw at 12 V)

• Shunt: Victron SmartShunt 500 A

Strategy

4 AWG is good for each individual battery leg (max 100 A).
The single cable after the SmartShunt must handle full inverter current, so it needs to be 2/0 or 4/0 AWG.

Wiring Layout 

Positive side — three separate runs:

Battery + → 100–125A fuse → 4 AWG → Inverter +

Battery + → 100–125A fuse → 4 AWG → Inverter +

Battery + → 100–125A fuse → 4 AWG → Inverter +

Negative side — SmartShunt placement:

Battery – → 4 AWG → SmartShunt “Battery –”

Battery – → 4 AWG → SmartShunt “Battery –”

Battery – → 4 AWG → SmartShunt “Battery –”

SmartShunt “System –” → 2/0 or 4/0 AWG → Inverter –

Fuse Panel (12 Circuit)

Components

Batteries

We will be using:

• 2x 100 Ah LiFePO4 batteries (DIY) - LiFePO4 100Ah Battery Build
• 1x 280 Ah LiFePO4 battery (Eco-Worthy) - Eco Worthy LiFePO4 280Ah Battery

Battery Charger

WAOUKS 14.6V 20A Charger 4 Series 12V LiFepo4 Battery Charger Smart Charger Aluminum Case with Cooling Fan for 4S 12V 12.8V LiFepo4 Battery Pack.

Specifications:

Product Name: 14.6V 20A Charger

Model: WA360-14620B

Dimensions: 180x90x63mm

Product Weight: 1.4 kg

Color/Material: Black/Aluminum Case

Suitable for Battery type: 4S 12V 12.8V 14.4V LiFepo4 Battery Pack

AC Input: 100~120Vac, 50/60Hz

Output Voltage: 14.6 Volt

Output Current: 20 Amp

Battery Protection: SCP,OVP,OCP,OTP

Charging Mode: Constant current - Constant Voltage - Trickle: Three-stage intelligent charging

Charging efficiency: ≥90%

Working temperature: -5 ℃ ~ +40 ℃

Storage temperature: -40 ℃ ~ +70 ℃

AC power cord, DC connector can be customized.

Operating Instruction

1. Before charging, please connect the DC terminal to battery first, and then connect the AC terminal.

2. After charging complete, unplug the AC terminal firstly, and then unplug the DC terminal.

3. No charging or after charging complete, be sure to unplug the DC terminal and AC terminal.

LED Indicator:

LED 1 red: Power on.

LED 2 red: Battery being charged.

LED 2 Flash: Battery will be charged completely soon.

LED 2 green: Battery has been charged completely.

Renogy Pure Sine Wave Inverter

See Renogy 12V 3000w Pure Sine Inverter

Victron Energy Shunt

See Victron Energy SmartShunt

Solar Charge Controller

See Renogy Rover 30A MPPT Charge Controller

Solar Panels

We have a flexible 100 watt solar panel and 2 rigid 100 watt panels.

References