Product Description

The BigBattery APEX 10K is the higher-output model in BigBattery's APEX line of all-in-one off-grid inverters for 48V battery banks. It combines a 10,000W split-phase 120/240V pure sine wave inverter, dual MPPT solar charge controllers, and a grid/generator battery charger in one indoor-rated unit, and per BigBattery it runs closed-loop with the NEXUS, ETHOS, and HUSKY 2 INV battery platforms. OffGrid Horizon is a family-owned authorized BigBattery partner serving customers across the US.

Who This Is For

Full-size off-grid homes, homesteads, and workshops that start and run heavier equipment — well pumps, compressors, and multiple 240V circuits at once. Per BigBattery, the APEX 10K is rated for motor loads up to 6 HP. If your load list is cabin-scale, the APEX 6.5K pairs with the same batteries; note the 10K has a single AC input (grid or generator), while the 6.5K has two.

Key Features

  • 10,000W rated output / 20,000VA maximum, split-phase 120/240Vac pure sine wave, per BigBattery
  • Motor load capacity of 6 HP, per BigBattery's published spec
  • Dual MPPT solar input — 5,000W + 5,500W (10,500W total), 125–450Vdc MPPT range, 550Vdc max open-circuit voltage, 22A max input per tracker
  • Built-in charging — up to 200A from solar, 120A from grid or generator, 200A max hybrid charge current
  • One AC input (grid or generator, not both simultaneously) with 10ms typical switching time
  • Closed-loop battery communications — RS485 / CAN / USB / dry contact; per BigBattery, compatible with NEXUS, ETHOS, and HUSKY 2 INV, with an optional Wi-Fi/GPRS module
  • Parallel up to 6 units; per BigBattery, three or more can form three-phase output
  • UL1741 listed, plus FCC Part 15 Class B, RoHS, EN61000-6-1, per BigBattery

Why BigBattery

BigBattery is a US-based company known for its LiFePO4 battery platforms; the APEX line is its matching 48V off-grid inverter family, designed so battery and inverter share data out of the box. Per BigBattery, APEX inverters carry a 5-year warranty backed by USA-based tech support.

Specifications

Rated output power 10,000W
Max output power 20,000VA
Output 120/240Vac single/split-phase, pure sine wave, 50/60Hz
Motor load capacity 6 HP
Battery voltage 48V nominal (40–60Vdc range)
MPPT trackers 2 (1 + 1)
Max PV input power 5,000W + 5,500W
MPPT voltage range 125–450Vdc
Max PV open-circuit voltage 550Vdc per tracker
Max PV input current 22A + 22A
Max solar charging current 200A
Max grid/generator charging current 120A
AC inputs 1 (grid or generator)
Switching time 10ms (typical)
Communication RS485 / CAN / USB / dry contact; optional Wi-Fi/GPRS module
Parallel capability Up to 6 units
Noise Under 60dB
Operating temperature 14°F to 131°F (derates above 113°F)
Protection IP20, indoor only
Dimensions 28.46 x 17.64 x 5.91 in
Weight 62 lb
Certifications UL1741, FCC Part 15 Class B, RoHS, EN61000-6-1
Warranty 5 years, as published by BigBattery
SKU INV035

All specifications per BigBattery's published product page and spec sheet.

What It Runs

The figures below are planning estimates only — actual wattage varies by model, so check appliance nameplates and confirm with your installer. Keep total running watts under the 10,000W rating, and keep motor-start surges within the 20,000VA maximum, per BigBattery.

  • Refrigerator plus chest freezer: roughly 300–700W running
  • 1.5 HP well pump (240V): roughly 1,500–2,200W running, with a start surge of 2–3 times that
  • Mini-split heat pump (one zone): roughly 500–1,500W running
  • Electric water heater element: roughly 4,500W while heating
  • Shop equipment (air compressor, saws): roughly 1,000–2,500W each while running
  • Lights and electronics: roughly 300–800W

Example (estimate): refrigeration 500W + well pump 1,800W + mini-split 1,200W + water heater element 4,500W + lights and electronics 600W is about 8,600W running — near the 10,000W rating, which is why staggering large loads still matters even at this size.

Installation

The APEX 10K is IP20 rated for indoor installation — per BigBattery, garages, utility rooms, and similar protected environments. Keep PV strings inside the 125–450Vdc MPPT window and never above 550Vdc open-circuit, including cold-weather voltage rise. Its single AC input connects to either the grid or a generator, not both at once — plan your changeover accordingly. Connecting 10,000W of output to a distribution panel involves grounding, bonding, permits, and local code — use a licensed electrician, and run the battery communication cable per BigBattery's manual for closed-loop operation.

Warranty & Support

Per BigBattery, the APEX 10K carries a 5-year warranty backed by USA-based tech support. As a family-owned authorized BigBattery partner, OffGrid Horizon can help with setup questions, troubleshooting, and claims. Returns require a Return Merchandise Authorization (RMA) — contact us before shipping anything back. Call (302) 496-3554.

Shipping

Ships within the United States. The unit weighs 62 lb and travels in protective packaging; please inspect the carton on delivery, note any damage with the carrier, and contact us right away so we can make it right.

Frequently Asked Questions

Is this a grid-tie inverter?

No. BigBattery sells the APEX 10K as an off-grid inverter: its AC input uses grid or generator power for charging and pass-through, and BigBattery's materials do not describe exporting power to the grid.

Can I connect both grid and generator?

Not at the same time — per BigBattery, the APEX 10K has one AC input that supports either grid or generator. If you need two dedicated AC inputs, the APEX 6.5K provides them.

Which batteries pair with it?

Per BigBattery, it runs closed-loop with the NEXUS 48V (15 kWh), ETHOS, and HUSKY 2 INV platforms, plus certain EG4 models. Heavy loads drain small banks quickly, so size storage to your daily consumption and make sure the bank's continuous discharge rating covers your peak draw.

How much solar can I connect?

Per BigBattery: 5,000W on one tracker and 5,500W on the other (10,500W total), with strings inside the 125–450Vdc operating window and below 550Vdc open-circuit.

Will it start a well pump?

Per BigBattery, the APEX 10K is rated for motor loads up to 6 HP, with 20,000VA of maximum output for starting surges. Verify your pump's horsepower and starting characteristics against those figures.

Can I expand later?

Yes — per BigBattery, up to 6 units can be paralleled, and three or more can form three-phase output.

Deciding between the 6.5K and the 10K? Call OffGrid Horizon at (302) 496-3554 — we are a family-owned shop and glad to walk through your load list before you buy.

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