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BigBattery APEX-6.5K Off-Grid Inverter

BigBattery APEX-6.5K Off-Grid Inverter
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$1,490.00
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$1,490.00
$1,250.00
$1,250.00 - $1,250.00
$1,250.00
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6,500W · Pure Sine · Off-Grid

BigBattery APEX-6.5K Off-Grid Inverter

The APEX-6.5K delivers 6,500W of continuous pure sine wave output (13,000VA surge) from a 48V battery bank, with dual MPPT solar inputs and 120/240V split-phase output for household and RV-class loads.

It parallels with up to 5 more units for more power or a 3-phase configuration, and switches over from grid to battery in about 10ms.

BigBattery APEX-6.5K Off-Grid Inverter
5-Year Warranty
Lowest Price Guarantee
Authorized BigBattery Dealer
Free Shipping
0% APR Financing
Expert Support: (303) 876-7654

Why the APEX-6.5K

Pure Sine Wave Output

Clean pure sine wave power safe for sensitive electronics, motors, and appliances that a modified-sine inverter can damage or run inefficiently.

Dual MPPT Solar Input

Two independent MPPT trackers (125–450Vdc each) mean strings facing different roof angles, or partial shading on one array, don't drag down the other.

Parallel Up to 6 Units, 3-Phase Capable

Stack up to 6 units for more output, and 3 or more units in parallel can form 3-phase power for equipment that needs it.

10ms Transfer Switch Time

Fast enough that most connected electronics won't reset during a grid-to-battery transfer.

UL1741 Listed

Certified to UL1741 along with RoHS, FCC Part 15 Class B, and IEC62109, the standards that matter for grid-interactive inverter installations.

5-Year Warranty

BigBattery backs the APEX line with a 5-year warranty.

What's Included

What's included: BigBattery APEX-6.5K Off-Grid Inverter

What You Get

  • 1 × BigBattery APEX-6.5K Off-Grid Inverter
  • Documentation

Battery bank and solar array sold separately.

Full Specifications

Model BigBattery APEX-6.5K
Continuous AC Output 6,500W
Surge/Peak Output 13,000VA
Output Waveform Pure sine wave
Output Voltage / Frequency 120/240V split-phase, 50/60Hz
Battery Input Voltage Range 40–60Vdc (48V system)
Solar (PV) Input MPPT range 125–450Vdc; up to 5,000W + 5,000W (2 MPPT channels); up to 18A per channel
AC Charging Input 80A max grid/generator charging current
Transfer Switch Time 10ms (typical)
Parallel Capability Up to 6 units; 3+ units in parallel can form 3-phase output
Peak Efficiency 99.9%
MPPT Tracking Efficiency 92–93%
Display / Monitoring WiFi capability noted; specific app/LCD details not published
Weight 48 lb
Dimensions 25.51"W × 16.14"D × 5.51"H
Operating Temperature 14°F to 131°F (derates above 113°F)
Cooling Intelligent fan
Certifications UL1741, RoHS, EN61000-6-1, EC61000-6-3, FCC Part 15 Class B, IEC62109-1, IEC62109-2
Warranty 5 years

Authorized BigBattery Dealer

We sell genuine BigBattery products backed by BigBattery's own warranty.

Lowest Price Guarantee

Find it cheaper from another authorized dealer? Call (303) 876-7654 before you order.

Real Support, Not a Ticket Queue

Sizing a battery bank or system? Call (303) 876-7654 and talk to a person.

BigBattery APEX-6.5K Off-Grid Inverter: Frequently Asked Questions

How much solar can I put on the APEX-6.5K?
Up to 5,000W per MPPT channel across its two independent trackers, for 10,000W total, each accepting 125–450Vdc. Two separate strings at different angles or facing different directions won't drag each other down.
Will this run 240V equipment?
Yes — it outputs 120/240V split-phase, which covers most household circuits and RV-class 240V equipment. Confirm your equipment's specific plug and wattage before ordering — call (303) 876-7654 if you're not sure.
Can I parallel multiple units together?
Yes, up to 6 units, and 3 or more in parallel can form 3-phase output for equipment that requires it. Call (303) 876-7654 if you're planning a multi-unit install and we can help you size it.
Does it have app or WiFi monitoring?
BigBattery notes WiFi capability on this model but doesn't publish specific app or LCD display details. Call (303) 876-7654 if remote monitoring is a requirement for your install and we'll confirm current features.
Will the power switch over automatically during a grid outage?
Yes, with a typical transfer time around 10ms. We'd still recommend a licensed electrician for any whole-home or transfer-switch installation.
Do you offer financing or price matching?
Yes. We offer 0% APR financing options through Affirm at checkout, and our Lowest Price Guarantee applies — if you find this product cheaper at another authorized BigBattery dealer, call us at (303) 876-7654 before you order and we'll take care of it.
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