Feedback on 4x EG4 Wallmount Batteries with EG4 12000XP Inverter

[twistedpear]

Hi everyone,

I’m setting up 4x EG4 Wall Mount Indoor 280Ah Batteries with an EG4 12000XP inverter and would love some feedback on my design before finalizing it. I want to ensure that I have safe, balanced, and efficient power distribution while also selecting the best busbar and overcurrent protection solution (fuses vs. circuit breakers).
My Proposed Setup
• Batteries: (4) EG4 Indoor 280Ah LiFePO4
• Inverter: EG4 12000XP
• Configuration:
• Two sets of two batteries in parallel using internal busbars
• Each battery pair connects to an external busbar (positive & negative)
• External busbars then connect to the inverter
• Overcurrent protection via 250A MEGA fuses (one per battery pair) or DC Circuit Breakers

Wiring Overview
1. Battery 1 & Battery 2 → Internal Busbar A → External Busbars (via 250A fuse) 2/0AWG
2. Battery 3 & Battery 4 → Internal Busbar B → External Busbars (via 250A fuse) 2/0AWG
3. External Busbars → Inverter (with appropriately sized cables) 4/0AWG



Questions & Requests for Recommendations
1. Busbar Recommendations
• I’m looking for a high-quality busbar that can handle at least 500A total current and supports 2/0 AWG for battery connections and 4/0 AWG for the inverter connection.
• I found the Victron Energy 6-Way MEGA Fuse Holder, but its M8 (5/16”) terminals may be too small for 2/0 and 4/0 AWG lugs. Has anyone used this in a similar setup?
• Are there better alternatives that support both battery and inverter connections?

2. Fuses vs. Circuit Breakers
• I currently plan to use 250A MEGA fuses per battery pair for protection before the external (+) busbar.
• Would it make sense to instead use 250A/300A DC circuit breakers?
• If circuit breakers are a better option, does anyone have recommendations for DC-rated models that can handle 48V & 250A?
3. Cable Length & Sizing
• I plan to keep all cables of equal length for proper current sharing.
• 2/0 AWG for battery to busbars, 4/0 AWG for busbars to inverter – does this seem sufficient for a max inverter draw of 250A DC?

I’d really appreciate any thoughts on my proposed setup and recommendations for busbars, fuses, or circuit breakers. If anyone has real-world experience with a similar configuration, I’d love to hear about any challenges or optimizations I should consider.

Looking forward to your insights—thanks in advance!

 

[Quattrohead]

You do not need extra bus bars or fuses.
Now this is not official advice but it is sound technical advice, pair one set of batteries and connect them to one set of the battery input terminals and pair your other set of batteries and connect those to the other set of battery input terminals on the inverter.
The inverter and the batteries all have their own circuit breakers built in.
You can string the battery communications for all four batteries together and then up to the inverter.

You will need two sets of parallel kits for the batteries and they already come with more than enough battery to inverter cables.

 

[twistedpear]

that's a great idea actually, as I am only using one pair of terminals on the 12000XP right now!