A 900 kW SDMO generator and a Harbor Freight solar generator are both “backup power,” the way a cargo ship and a kayak are both boats. Technically true. Practically not much help when you are trying to make a purchasing decision.
I am the service manager for an industrial power company in Miami. For the past 14 years, I have coordinated emergency generator work for facilities that cannot afford to go dark: cold-storage plants, medical buildings, high-rise condos. When a storm watch turns into a warning, those facilities call. Most of the expensive failures I see did not start during the storm. They started months earlier, in a meeting where somebody was comparing price tags.
Here is my opinion, stated directly:
If you are choosing between a solar generator from Harbor Freight and a 900 kW SDMO diesel genset, you are not comparing two backup options. You are comparing two different realities, and a lower price cannot bridge that gap. Price only becomes meaningful after you account for what the equipment must do—and what failure costs.
First, get the energy scale straight
A “solar generator” is usually a battery, an inverter, and a solar charge controller in one box. It is a legitimate product for RVs, construction trailers, emergency lighting, or keeping a router and laptop alive. But let’s put the numbers next to each other. A 900 kW SDMO generator can deliver 900,000 watts continuously when needed. Most portable solar generators offer single-digit kilowatt-hours of stored energy and only a few thousand watts of output. A cold-storage warehouse can consume more energy in the first hour of an outage than a portable unit can store in a week.
I’m not dismissing the category. Several commercial clients keep a small solar generator specifically to run security cameras and the network closet when everything else is dark. That is a smart use. But it is a tool for small loads, not for a building’s critical systems. The error is treating it as an alternative to an industrial set.
Inverter vs generator: the real question is what has to start
Someone inevitably asks me “inverter vs generator—which is better?” At the residential or light-commercial scale, that is a legitimate question. Inverter generators use electronics to produce stable, clean power; they are quieter and more efficient at partial load. For powering laptops, phone chargers, and lights, they are often the better tool.
The difference shows up when electric motors are involved. Motors do not politely ask for power; they demand starting current several times their running current for the first second or two. That momentary surge is where small generators fail. A small inverter unit may start a refrigerator in a home, but it will not start a 30 kW industrial compressor, much less several of them. It is not a quality problem; it is a physical limitation.
An industrial diesel set like the 900 kW SDMO generator is engineered with a synchronous alternator, rotating mass, and transient overload capability specifically so it can start large motor loads without voltage collapse. That capability shows up in the engineering spec, not in the sticker price.
The transfer switch is where budget cuts end up hurting
If you buy a powerful, reliable genset and screw up the transfer switch, you still have nothing. Generator transfer switch installation is often the real point of failure, even more than the generator itself. The transfer switch is what detects the outage, starts the engine, transfers the load, and later transfers back. Without it functioning as a system, the best generator is only a very expensive sculpture.
In March 2024, our after-hours line got a call from a property manager in Aventura. The grid had failed, the building’s backup set had not started, and an elevator was stuck between floors. We found a healthy generator with a full fuel tank. The automatic transfer switch simply never sent the crank signal because a two-wire start connection had never been terminated during installation. If I remember correctly, the commissioning line item had been cut from the project to save around $1,600.
That story is why I respect the code requirements. According to NFPA 110, the standard for emergency and standby power systems (Source: NFPA, nfpa.org), a Level 1 system serving life-safety loads must transfer the load from the normal source to the emergency source within 10 seconds. The only way to know the system can do that is to test it under load before an emergency. Skipping commissioning to cut the budget usually means you discover the problem at the worst possible moment.
The generator itself was not the problem in that Aventura job. The transfer switch installation was. But the final cost, including after-hours labor and an elevator contractor, was several times the amount the project tried to save.
Why I keep recommending SDMO generators in Miami
I will admit my bias: my company sells and services SDMO generators in Miami. If you search for an SDMO generator Miami support center, I want you to find us. But that is exactly the point I keep making to clients. A backup generator is a 20-year relationship, not a one-time purchase. Parts availability, technical documentation, manufacturer support, and someone who can come out after a hurricane matter as much as the bid price.
There is another detail that gets overlooked in a price comparison. According to ISO 8528, generator sets are classified by operating duty. A machine rated for emergency standby power is intended for limited hours and intermittent operation, not for running for days as a continuous source. If your plan in South Florida is to run on generator power for 48 hours after a hurricane, you need to account for that duty cycle, or you will be disappointed by the set’s capability. A cheap quote often hides this nuance: it says “900 kW” without telling you under which duty rating that number applies.
That is why the value argument matters more than the price argument. Two quotes can both say “900 kW” and still describe different machines—with different alternators, different control systems, different starting capability, and different service support behind them.
The objection I expect
Let me answer the criticism I usually get: “Easy for you to say; you don’t have my budget.” Fair. I am not saying everyone should buy the most expensive option. I am saying the first calculation should be the cost of being down, not the cost of the generator.
If your loads are genuinely small—lights, a few outlets, a modem—a portable inverter generator or a small solar generator might be exactly right. I recommend those in the right context. But if your facility depends on refrigeration, elevators, pumps, or any motor-driven equipment, the cheap option is only cheap until the first moment it is asked to do real work.
I can only speak to the commercial and industrial world where I work. If you are buying a generator for a campsite or an RV, this article is probably overkill. The principle still applies, though: size the equipment to the consequence of failure, and then compare prices.
Don’t compare invoices; compare outcomes
I don’t expect this opinion to make me popular with people selling bargain generators. I’ve been on too many emergency calls where the difference between a smooth night and a disaster came down to decisions made months earlier. The cheapest backup power is only cheap until the moment the grid goes down and the machine cannot carry the load.
So here is my position again, with no apology: In backup power, value is not about spending more; it is about paying for capability, installation, and support that the load actually requires. Compare the cost of being down with the cost of the generator. The price tag will make a lot more sense after you do.
