How to Size an EG4 Solar System: Inverters, Batteries, and Backup

An EG4 solar system can back up your whole home, take you off-grid, or lower your power bill, but only if the parts are sized to match. This guide shows you how to choose the right EG4 inverter, size your battery bank, and pick the solar to feed it.

Step 1: Pick your goal

• Backup: keep essentials running during outages.
• Off-grid: run entirely on solar and battery, no utility.
• Grid-tied with storage: use solar daily and bank the rest.

Step 2: Choose the inverter

EG4 splits into off-grid all-in-ones and hybrid inverters:

• Off-grid: the 3000 EHV for cabins, RVs, and small loads, plus the 6000XP and 12000XP for larger off-grid homes.
• Hybrid (grid, solar, and battery): the 12kPV and 18kPV for whole-home, and the FlexBOSS18 and FlexBOSS21 for flexible, expandable builds.

Match the inverter to your continuous load (everything that runs at once) and its surge capacity for big startups like well pumps and AC.

Step 3: Size the battery bank

Add up the kWh you use during the hours you want to cover. EG4 batteries scale from 5.12 kWh server-rack units (LifePower4, LL-S) to 14.3 and 16 kWh WallMount batteries, in indoor and all-weather versions, and stack in a cabinet or rack to reach your target. As a rough start, a day of essential backup is often 10 to 30 kWh depending on the home.

Step 4: Add solar

Size your array to recharge the bank and cover daily use on an average day. Your inverter's PV input rating sets the ceiling; the 18kPV and FlexBOSS21, for example, accept large arrays.

Step 5: Manage and charge

• EG4 GridBOSS: microgrid and load management to run multiple inverters and prioritize critical loads.
• EG4 Chargeverter: fast AC charging from grid or generator when solar is short.

Common mistakes

• Buying the inverter first, then finding the battery or array does not match it.
• Undersizing the battery for the loads you actually run overnight.
• Ignoring surge loads, so the inverter trips when the AC or pump starts.

Get free system design

Tell us your goal, your loads, and your budget, and we will build a complete, compatible EG4 parts list. Shop EG4 or contact our team.