Selectronic SP PRO: the Australian-made inverter built for the hardest loads.
Designed and manufactured in Victoria by a company that has been making power electronics since 1964, the SP PRO is the inverter we point to when a property has motors that start no matter what — bore pumps, compressors, welders, cold rooms. A 5 kW unit that runs 7 kW for half an hour and 12 kW for thirty seconds. AC coupling to twice its own rating. Twelve units in a chain. Here's what the SP PRO does, where it belongs, and what it asks in return.
Designed in Lismore · installed by accredited localsWhat the SP PRO is
Australian owned, designed, manufactured, supported
Selectronic builds the SP PRO in Wantirna South, Victoria, and has been building power electronics in Australia since 1964. When something on a property ten hours from the nearest city has a question, the people who designed the board are in the same time zone. That is rarer than it sounds.
3 to 20 kW · 24, 48 and 120 V
Series 2i runs from the 3 kW SPMC240 on 24 volts, through the 48-volt SPMC480/481/482 at 3.5, 5 and 7.5 kW, to the 120-volt SPLC1200 and SPLC1202 at 15 and 20 kW. Up to four units per phase and twelve in total, which is how Selectronic reaches 240 kW on one Powerchain system.
Rated for 30 seconds and for 30 minutes
Selectronic publishes three numbers, not one. The 5 kW SPMC481 delivers 7 kW for 30 minutes and 12 kW for 30 seconds. The 7.5 kW SPMC482: 11.25 kW for half an hour, 18 kW for 30 seconds. The 20 kW SPLC1202: 30 kW for half an hour, 33 kW for 30 seconds — and 35 kW for a full minute. That half-hour figure is the one that matters when a compressor cycles all afternoon.
6 W idle, under 30 ms transfer
An inverter that sits awake all night on 6 watts is an inverter that leaves your winter sun for the house. Grid or generator to battery changeover in less than 0.03 seconds keeps pumps, computers and controllers running through it. Indoor unit, IP43, rated from −10 to 60 °C.
Where the money goes
“Either way you're going to spend the money. It just depends who you want to give it to — soft starts and efficient appliances, or Victron and Selectronic.”
— Mike Haydon, The Off Grid Shop
Motors, and the two ways to start them
Every all-in-one hybrid publishes a peak figure — 150% for ten seconds, twice rated for ten seconds — and ten seconds is enough to get a motor spinning. What it doesn't cover is the compressor that starts every four minutes for the whole of a January afternoon, or the bore pump that runs for an hour while the header tank fills, or the welder that runs a bead, stops and runs another. That is a thirty-minute problem, and most inverters don't publish a thirty-minute rating at all.
You have two honest ways to solve it. Fit soft starters to the big motors, buy efficient appliances, and design the loads down to what a modest inverter carries — that works, and we do it. Or buy an inverter that shrugs at the motor: Selectronic, or the heavier Victron units. The SP PRO's 30-minute and 30-second ratings are the reason it earns its place on farms and workshops, and the reason it costs what it does. Our three-phase page walks through the same trade-off across every brand we design with.
Managed AC Coupling: up to twice the inverter's rating
Selectronic has been controlling grid-tied solar inverters inside off-grid systems since 2010, and its version is the most refined we've used. With a Selectronic Certified inverter on the AC side — SCERT versions of Fronius and FIMER (formerly ABB) grid-tied inverters; Selectronic publishes the current list — the SP PRO manages the solar in 0.1% steps and accepts up to twice its own continuous rating per phase in AC-coupled PV, from as many as five certified inverters. Any other grid-tied inverter is managed by frequency shift up to the SP PRO's continuous rating. For the property that built the shed first with a grid-connected system and wants the house off grid later, that is the cleanest path we know of. The full story is on our grid-connected inverter off grid page.
| Model | Battery voltage | Continuous | 30 minutes | 30 seconds |
|---|---|---|---|---|
| SPMC481 | 48 V | 5.0 kW | 7.0 kW | 12.0 kW |
| SPMC482 | 48 V | 7.5 kW | 11.25 kW | 18.0 kW |
| SPLC1200 | 120 V | 15 kW | 23 kW | 33 kW |
| SPLC1202 | 120 V | 20 kW | 30 kW | 33 kW |
Figures from Selectronic's SP PRO Series 2i datasheet. The smaller 24-volt and 48-volt units follow the same pattern. Three units make a three-phase system; four per phase and twelve in total is the ceiling.
Three inverters, three phases, one system
Three-phase off grid used to mean three single-phase inverters locked together, and Selectronic is one of the two platforms that made that reliable. It still is: three SPMC482s give 7.5 kW per phase continuous and 18 kW per phase for thirty seconds, and three SPLC1202s give 20 kW per phase with 33 kW behind each one for motor starts. The all-in-one three-phase hybrids are neater and cheaper, and for many properties they're the right call. When the loads on one phase are heavy and unforgiving, the old way — done with Selectronic — is still the way that never blinks.
The per-phase limit applies to every three-phase system, not just this one: a load on one phase only ever sees that phase's inverter. Balancing loads across phases is design work, and it's where we start.
Selectronic against the platforms we design with
| What matters | Selectronic SP PRO | Victron | All-in-one hybrids |
|---|---|---|---|
| Where it's made | Australia — Wantirna South, Victoria | Netherlands-based company | Mostly China |
| Surge rating published | Continuous, 30 minutes and 30 seconds | Continuous and peak | Peak for 10 seconds |
| AC-coupled solar | Up to 2× continuous with certified Fronius/FIMER; 1× generic | Frequency shift, 1:1 rule of thumb | Varies; often switched off before a full battery |
| Solar input | Battery inverter — solar arrives by AC coupling or DC charge controllers | Separate MPPTs, or built in on RS models | Built-in MPPTs |
| Monitoring | Select.live portal; SP LINK for configuration | VRM, GX devices | Manufacturer app |
| Idle draw | 6 W | Model-dependent; search mode available | Model-dependent |
| Enclosure | IP43 — plant room | MultiPlus-II IP22 — indoor | IP65–IP66 — outdoor capable |
| Warranty | 5 years; 10 when registered within 180 days of purchase with a Select.live serial | 5 years | Typically 10 years |
Chosen on merit, for the property in front of us. Selectronic wins the properties where the loads are hard and the budget respects that. We don't hold stock, so nothing on a shelf tips the choice.
What the SP PRO asks in return
It's a battery inverter. There's no solar input on the box. Solar arrives either through Managed AC Coupling with a certified grid-tied inverter, or through DC charge controllers on the battery. That is a strength — it's why the AC coupling is so good — and it's also one more piece of equipment in the design.
It lives indoors. IP43 means a plant room, a shed with a proper enclosure, or a garage wall — not an outside wall in the weather. Ventilation and clearance are part of the design.
You spend the money. The SP PRO is a premium inverter and priced like one. Against that: it's the one you buy so the soft starters, the load-shedding relays and the second inverter stay on the shelf. Which side of that ledger is cheaper depends on the property, and the design works it out honestly.
Configuration is an installer's job. SP LINK, Selectronic's setup software, runs on a Windows laptop and rewards people who know it. Owners live with Select.live, the monitoring portal, which is simple. Registering the warranty within 180 days of purchase, with a Select.live device fitted and its serial number supplied, is what takes the warranty from five years to ten — we do it as part of handover.
Is Selectronic right for your property?
Tell us about the motors — pumps, compressors, cold rooms, welders — how long they run and how often they start, and whether there's grid-connected solar to bring across. If the SP PRO is the honest answer, the design shows the 30-minute and 30-second figures against your actual loads. If soft starters and a lighter inverter get you there for less, the design says that instead.
Prefer to talk it through? Call or text 0483 927 257 — Lismore HQ, local voices.
Selectronic questions, answered
Is Selectronic made in Australia?
Yes. Selectronic describes itself as Australian owned, designed, manufactured and supported, and builds the SP PRO Series 2i in Wantirna South, Victoria. The company has been building power electronics in Australia since 1964.
What is the SP PRO's surge capacity?
Selectronic publishes a 30-minute and a 30-second rating for every model. The 5 kW SPMC481 delivers 7 kW for 30 minutes and 12 kW for 30 seconds; the 7.5 kW SPMC482 gives 11.25 kW and 18 kW; the 20 kW SPLC1202 gives 30 kW and 33 kW. The half-hour rating is what carries compressors and pumps that cycle all afternoon.
Can I AC-couple my Fronius inverter to a Selectronic?
Yes — that's Selectronic's specialty. With a Selectronic Certified inverter — SCERT versions of Fronius and FIMER (formerly ABB) units, per Selectronic's current list — the SP PRO manages the solar in 0.1% steps and accepts up to twice its continuous rating per phase in AC-coupled PV from up to five certified inverters. Other grid-tied inverters are managed by frequency shift up to the SP PRO's continuous rating.
Does Selectronic do three phase?
Yes, with three units — one per phase — and up to four per phase, twelve in total. Three SPMC482s give 7.5 kW per phase continuous and 18 kW per phase for 30 seconds; three SPLC1202s give 20 kW per phase with 33 kW behind each. Loads on one phase only ever see that phase's inverter, so balancing them is part of the design.
What warranty comes with an SP PRO?
Five years as standard in Australia and New Zealand, extended to ten years when the warranty is registered within 180 days of purchase with a Select.live serial number supplied. We register it at handover.
Does the SP PRO have solar inputs?
No — it's a battery inverter-charger. Solar arrives either by Managed AC Coupling with a certified grid-tied inverter or through DC charge controllers on the battery bank. That separation is why its AC coupling is so capable, and it's one more component the design accounts for.