Does a Sol-Ark 15K's GEN Port Take a Generator or More Solar?
Summary
Either one, but only one at a time. The 15K datasheet (PS-00001 Rev. 8) describes GEN as a bidirectional port for a fuel generator, AC-coupled PV or an AC load such as an EV charger, rated at 80 A and 19,200 W at 240 V. The installation guide (Rev. 8, effective March 13, 2026) says only one AC source can be connected to the GEN terminal at a time.
With a generator
The guide says the 15K only supports 120/240 V split-phase generators and can use one to charge the battery through the GEN port. Automatic generator start is built in as a 2-wire start, and a generator with 2-wire start compatibility gets a weekly exercise run, by default at 8:00 a.m. every Monday.
Because the port is rated at 80 A at 240 V, a 20 kW home standby generator on that port still passes no more than 19,200 W. On a 208 V service the ceiling drops to 16,640 W.
With AC-coupled solar
The output of an existing grid-tied string inverter or microinverters can go into the same port, up to the same 19,200 W. The guide limits AC coupling to the GEN terminal, citing several drawbacks, and says coupling on the LOAD terminal is no longer supported from firmware MCU 7.2.2.8 onward. Another section of the same guide still describes coupling into the GEN or LOAD terminals, so the document is not consistent on this.
A house that has both a generator and an older solar array can put only one of them on GEN.
How the 12K and 18K compare
| 12K-2P-N | 15K-2P | 18K-2P | |
|---|---|---|---|
| Continuous AC output | 9,000 W plus 3,000 W DC from batteries | 15,000 W | 18,000 W |
| Grid passthrough | 63 A (product page says 50 A) | 200 A | 200 A |
| GEN port | Not stated on the datasheet | 80 A, 19,200 W | up to 120 A, 28,800 W AC-coupled |
| MPPTs | 2 | 3 | 3 |
| Battery charge/discharge current | 185 A | 275 A | 350 A |
The 18K datasheet (Rev. 8) gives the GEN port a maximum current of 120 A in its table but calls it a "(150 A) GEN terminal" in its component list, so that model carries two figures as well.
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Sources
- Sol-Ark — 15K-2P-LV Datasheet (PS-00001 Rev. 8)
- Sol-Ark — 15K Installation Guide (Rev. 8, effective March 13, 2026)
- Sol-Ark — 12K-2P-N Datasheet (SK150-0003 Rev 3)
- Sol-Ark — Essentials 12K-2P
- Sol-Ark — 18K-2P-LV Datasheet (PS-00036 Rev. 8)
- Sol-Ark — Product Document Library
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