SolarMax SM-ONYX-UL-10KW 10kW Single-Phase Hybrid Inverter

The SM-ONYX-UL-10KW is SolarMax's flagship single-phase hybrid and the only machine in the range that is not an Axpert-family design: IP66, three MPPTs, 16kW of PV input, 210A of battery current, nine units in parallel, and a real BMS handshake over CAN or RS485. It sells in Pakistan for Rs 425,000-480,000 as of 2 August 2026 - five live sellers, with three of them (W11Stop, SunSolar, BuySolar) at Rs 440,000, c-power.pk cheapest at Rs 425,000 and Volteck highest at Rs 480,000.

Two things to fix before you shop. It is single-phase, whatever a price-comparison page tells you - SolarMax's own datasheet says "220V/230V/240V (Single Phase)", and the three-phase ONYX models start at 12kW. And the cheapest listing is also the least accurate one: c-power.pk's page prints IP65, -10 to 50C and 6-unit parallel against the datasheet's IP66, -25 to 60C and 9-unit parallel, and sells the unit under c-power's own 2-year replacement warranty rather than the 5-year parts term printed on SolarMax's datasheet. Rs 15,000 saved, three years of parts cover gone.

Specifications

The 210A battery figure is the one that separates this from the rest of the SolarMax range: at 48V that is the full 10kW drawn from the pack alone, so the inverter is not the bottleneck in a lithium-backed whole-house backup. Your battery bank has to be able to deliver it, which most single 5kWh modules cannot.

Honest assessment

Pros. This is a modern ESS-class inverter at a Pakistani-brand price. Three MPPTs with 16kW of PV means you can oversize hard and split a roof across three orientations without a second inverter - unusual below Rs 500,000 here. IP66 and a -25 to 60C envelope are genuine outdoor ratings, not marketing. 210A of charge and discharge, 9-unit parallel, AC-coupling support and generator input cover essentially every residential and small-commercial topology in Pakistan. The BMS talks CAN and RS485 with a self-adapting lithium charge curve, so a lithium bank runs under BMS control rather than on hand-set voltages. And the datasheet is published, free, complete, with named IEC standards - a low bar that most badge brands still fail.

Cons. Nothing about the warranty is enforceable on paper. The datasheet's "5 YEARS" carries a "Terms and Conditions Apply" footnote and those terms are published nowhere; no warranty policy PDF exists on solarmax.pk, and no user manual is downloadable at all - the downloads page states customer care can send you one on request. The datasheet contradicts itself on the battery window (40-64V in the table, 40-60V on the cover). No approved-battery list is published, so "compatible with lithium" is your installer's problem to prove, not the brand's to document. And at Rs 440,000 you are paying Rs 50,000 more than a Solis 10kW single-phase hybrid in the same store, for a brand with no published compatibility list, no verifiable service network and no resale market.

Who should buy. Someone with a big, awkward roof and a real lithium bank who has read this datasheet, is buying from a seller whose listing matches it, and is getting "SM-ONYX-UL-10KW, 5 years parts" written on the invoice. Someone who wants documentation, firmware support and a warranty they can appeal to should buy Solis or Goodwe and pay the difference. Someone who just needs 10kW cheaply should look at Knox's Krypton 13002 at Rs 270,000 and accept a lesser machine honestly.

Pakistan reality check

Check the listing against the datasheet before you check the price. This model is sold under at least four names - SolarMax's own "ONYX UL 10kW", W11Stop's "ONYX-DUAL 10KW PV16000", SunSolar's "Onyx DUAL (PV16000)", c-power's "Onyx 10KW" with the model code written as SM-ONYX-DUAL-10KW. Volteck and SunSolar quote the datasheet correctly (16,000W PV, 3 MPPT, 210A, IP66, 35 kg, 420x800x240 mm, 9 parallel). C-Power does not: IP65, -10C to 50C, six units parallel. Those are Orion Ultra numbers pasted onto an Onyx page. A seller who cannot describe the machine will not be much help when it faults.

The warranty you are actually buying. SolarMax's own datasheet: 5 years unlimited parts, lifetime free service. SunSolar encodes that in its product title - "(5Y)". C-Power sells it with "2 years (Replaced Warranty)" of its own. Both are Rs 425,000-440,000. The difference between those two invoices, three years in, is the entire cost of a power board. Ask which entity is on the hook, and get the answer in ink.

Derating is the specification Pakistan actually cares about. The datasheet's temperature line reads "-25C-60C (>45C Derating)". Ambient inside a closed utility room in Multan or Jacobabad in June clears 45C easily, and this is a 35 kg sealed IP66 box relying on smart cooling. Plan the installation for the derate: shaded, ventilated, wall-mounted at height, not in the same cupboard as the battery bank. IP66 means you may mount it outdoors; it does not mean you should mount it in the sun.

No approved-battery list exists, so make the seller commit. Deye publishes a ~120-pack approved battery list with per-brand setup codes. Pylontech publishes a versioned inverter compatibility list. SolarMax publishes neither. The Onyx UL will self-adapt to a BMS over CAN or RS485, which is the right architecture, but "will it talk to this specific pack" is an open question that you should close in writing with the seller before delivery - naming the battery brand and model on the same invoice as the inverter.

Three MPPTs, but not three equal MPPTs. The cover page headline is "Support high Power Module with 30A PV Input Current". The spec table says 30A / 22A / 22A. If your installer designs three identical high-current strings on the assumption of 30A per tracker, two of them are over-specified against the datasheet. Put the biggest, highest-current string on MPPT 1.

Price context vs rivals (August 2026)

Same store, same day - W11Stop, 2 August 2026:

The Onyx UL sits in the middle of a shelf where its paper spec is arguably the best under Rs 475,000 - and where its documentation is the worst. Note the last row: Rs 40,000 more than the Onyx buys a Solis 12kW, 20% more inverter from a manufacturer with a published compatibility list and a global service structure. That is the trade this page exists to make explicit. For the cheaper Axpert-class alternative inside the same brand, see the ORION ULTRA 11kW at Rs 245,000-345,000, and the brand hub for who SolarMax actually is.