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48V Hybrid Inverter · Dual AC Input — Grid + Generator
The APEX-6.5K converts stored DC power from a 48V lithium battery bank into full-strength 120/240V split-phase household electricity — the same clean, pure sine wave power you'd get from a utility line. Unlike single-input inverters, it keeps a dedicated grid connection and a dedicated generator connection wired in side by side, so cabins, homesteads, and off-grid residences can lean on solar by day and fall back on either backup source without swapping a plug.
Rated for 6,500W of continuous output with up to 13,000VA of surge headroom to start motors, pumps, and compressors without tripping.
120/240V pure sine wave at 50/60Hz — the same wave shape a utility delivers, safe for motors, electronics, and anything sensitive to rough power.
Two independent MPPT trackers pull up to 10,000W combined, adjusting continuously as sunlight shifts through the day.
Two separate AC inputs let grid and generator both stay connected at once, with solar charging independently on top — no manual switchover.
Routes up to 80A straight to critical loads — enough to carry a well pump or HVAC run without staging separate circuits.
Stack multiple APEX-6.5K units for larger homes, or connect three or more to generate a full three-phase output.
Guards against over/under-voltage, overload, short-circuit, and overheating, tripping a safe shutdown instead of letting a fault spread.
Keeps working from well below freezing up to 131°F, derating only once temperatures climb past 113°F.
Most off-grid inverters make you choose between a grid connection and a generator connection at any given moment. The APEX-6.5K keeps both wired in permanently — two independent MPPT solar trackers cover day-to-day charging for a combined 10,000W, and when the sun isn't enough, the system can draw from utility power and a generator at the same time instead of switching between them.
At 48 lbs and roughly 25.5 × 16 × 5.5 inches, it's noticeably more compact than the larger APEX-10K, which matters when floor space in a utility room or power shed is tight. The same 14°F to 131°F operating range and layered protection against over-voltage, over-current, short circuits, and heat buildup carry over, so a fault trips a safe shutdown instead of spreading through the rest of the system.
| Rated output power | 6,500 W |
| Max output (surge) | 13,000 VA |
| Output voltage | 120/240 Vac split-phase |
| Frequency | 50/60 Hz |
| Waveform | Pure sine wave |
| Motor load capacity | 4 HP |
| Switching time | 10 ms (typ.) |
| Max efficiency | 99.9% |
| Battery type | Li-ion / lead-acid / user-defined |
| Rated battery voltage | 48V |
| Battery voltage range | 40–60 Vdc |
| Max grid/gen charge current | 80 A |
| Max hybrid charge current | 140 A |
| Max solar charge current | 140 A |
| MPPT channels | 2 (1+1) |
| Max solar input power | 5,000W + 5,000W |
| Max input current | 18A + 18A |
| Max open circuit voltage | 550 Vdc / channel |
| MPPT voltage range | 125–450 Vdc |
| MPPT tracking efficiency | 93% |
| AC input | 2 inputs, grid + generator* |
| Input voltage range | 65–140 Vac |
| Input frequency range | 50/60 Hz |
| Bypass overload current | 40 A |
| Pass-through capacity | 80 A |
| Dimensions | 25.51 × 16.14 × 5.51 in |
| Weight | 48 lbs |
| Ingress protection | IP20 (indoor only) |
| Operating temperature | 14–131°F |
| Noise level | <60 dB |
| Cooling | Intelligent fan |
| Communication | RS485 / CAN / USB / dry contact / CT |
| Optional module | Wi-Fi / GPRS |
| Integrated breakers | Utility / load / battery / PV |
| Parallel capacity | Up to 6 units, 3-phase at 3+ |
| Brand / model | BigBattery APEX-6.5K |
| GTIN | 00199874185712 |
*Grid and generator each get their own dedicated AC input and can be connected simultaneously. Certifications: UL1741, RoHS, EN61000-6-1, EC61000-6-3, FCC Part 15 Class B, IEC62109-1/2.
Built around 48V lithium battery banks (40–60Vdc), with full closed-loop communication for the packs below. Other 48V lithium or lead-acid batteries can run as a user-defined battery type, just without the live communication link.
It depends on your total connected load. At 6,500W continuous (13,000VA surge) it comfortably covers most efficient homes and cabins, but a full load calculation is worth doing before sizing your system — especially if you're running well pumps, electric heat, or several large appliances at once.
Yes. The APEX-6.5K has two independent AC inputs — one for grid, one for generator — plus solar charging on its own circuit, so all three can stay connected simultaneously. (The larger APEX-10K shares a single AC input between grid and generator instead.)
Any 48V lithium battery bank works as a general-purpose battery. Full closed-loop communication is supported with BigBattery NEXUS, ETHOS, and HUSKY2 INV, plus EG4's 280Ah and 314Ah packs.
No — it's rated IP20, meaning indoor or fully enclosed installation only, such as a garage, utility room, or dedicated power shed.
Yes, up to six units can be paralleled together, and three or more can be configured to produce a three-phase output for larger installations.
The APEX-10K outputs more power (10,000W vs. 6,500W continuous) and suits larger homes, but shares one AC input between grid and generator. The APEX-6.5K trades some output capacity for two independent AC inputs, a smaller footprint, and about 14 lbs less weight — a better fit where simultaneous grid-and-generator backup matters more than maximum wattage.
Given the voltages and currents involved, installation should be handled by a qualified, licensed electrician or solar installer familiar with your local code requirements.
Free shipping on all orders within the mainland US (Hawaii, Alaska and overseas territories excluded - a freight forwarder is required). Orders ship directly from our brand partners' warehouses across the U.S. Order confirmation is emailed immediately; if an item is unexpectedly backordered we notify you before your card is charged. In-stock items are processed within 1-4 business days (cut-off 4:00 PM EST), transit is 3-6 business days, and tracking is emailed within 24 hours of shipment. Typical delivery is 4-10 business days from purchase. Minimum order value is $69.
You have 30 days from the delivery date to initiate a return (35 days for orders placed Nov 25-30 and Dec 25-31). Items must be unused, in original packaging with tags attached, and returns require prior authorization from our team.
To start a return: +1 (307) 317-7213, hello@ecosolarkits.com, or live chat. Read the full return and refund policy
