SDMO Generators: Expert Answers to Your Backup Power Questions

When the power goes out, every minute counts. I've been in the emergency power business for 12 years, deploying generators for hospitals, data centers, and factories. Here are the questions I get asked most often — with honest answers, not sales fluff.

What is an SDMO generator?

SDMO is a French manufacturer of industrial diesel generators, part of the Kohler group since 2012. They make everything from compact 20 kW units to massive 1250 kVA systems. What most people don't realize is that SDMO generators use Kohler's engine and controller technology, which means you're getting the same engineering as the premium Kohler line — often at a slightly lower price point because of the brand positioning. (Source: Kohler-SDMO product line specifications, 2024.)

How does a whole house generator work?

From the outside, it looks like a generator is just a big engine that turns on automatically. The reality is a bit more involved. A whole house generator (like an SDMO with an automatic transfer switch) continuously monitors your utility power. When the grid fails, the transfer switch disconnects your home from the line and signals the generator to start. Within 10–30 seconds, your critical circuits — fridge, lights, HVAC — come back on. One thing vendors won't tell you: the transfer switch is actually the most important part. Skimp on that, and even a 100 kW generator won't protect your electronics. I saw this firsthand in March 2024 when a client installed a high-end unit but paired it with a cheap switch — the surge fried their control board.

Is a 100 kW SDMO generator enough for a commercial building?

It depends entirely on your load profile. A 100 kW generator (about 125 kVA) can handle a small office building with minimal HVAC, but if you're running a full computer server room or industrial machines, you'll likely need more. Here's the insider tip: generator capacity isn't just about total wattage — it's about starting loads. A 100 kW unit might start a 30 HP motor, but two motors starting simultaneously could trip the overload. In Q4 2023, I specified a 100 kW SDMO for a dental clinic with four compressors — it worked perfectly because we staged the startup sequence. But if you have unpredictable loads, I'd recommend stepping up to 150 kW or more. (Note: these ratings are as of January 2025; verify with your local dealer.)

SDMO vs Generac: which is better?

I can't say one is universally better — that's the kind of absolute statement that gets people into trouble. Here's what I've learned after deploying over 200 units: Generac is excellent for residential and light commercial because they have a massive dealer network and parts are everywhere. SDMO (Kohler) leans more toward industrial and mission-critical applications. If you're a homeowner who wants a simple 20 kW air-cooled unit, Generac is probably your best bet. But if you're running a factory, hospital, or any facility where downtime costs thousands per hour, the SDMO line — especially liquid-cooled models above 50 kW — offers better durability and longer service intervals. Don't take my word for it: check the warranty terms. SDMO's commercial warranty often covers 3 years / 3000 hours, while some Generac residential units cap at 2 years. (Pricing note: expect to pay 20–30% more for an equivalent SDMO unit, but total cost of ownership can be lower over 10 years. Verify current quotes.)

What about the 650 kVA SDMO generator? Who needs that?

I'll be honest: most people don't. A 650 kVA unit (about 520 kW) is a beast — it weighs around 7–8 tons and requires a concrete pad, dedicated fuel supply, and regular maintenance contracts. I've only specified these for large manufacturing plants, data centers, and hospital complexes. One common mistake I see: facilities overestimate their load. I assumed a 5000 sq ft office needed a 650 kVA generator. Didn't verify the actual load. Turned out they only needed 200 kVA. That happened in 2021 — the client wasted $40,000 on oversizing. So before you buy a 650 kVA SDMO, get a professional load study done. It'll save you money and headaches. Bottom line: if your peak load is under 400 kW, look at smaller models. The 650 is a specialty tool, not a starter unit.

Can I use a portable generator like the Predator 3500 for whole house backup?

Technically, yes — you can plug it into a transfer switch and power a few circuits. But from the outside, it looks like a cheap solution. The reality is it's a huge hassle. Portable generators aren't designed for continuous runtime; they need refueling every 6–12 hours. The Predator 3500 is a great inverter generator for camping or tailgating — lightweight, quiet, efficient. But for whole house backup during a multi-day outage, you'll be running to the gas station at 2 AM. I had a client in 2022 who tried this after Hurricane Ian: they ran out of gas, couldn't find a station open, and had to throw away $1,000 worth of food. If you need whole house backup for more than 8 hours, invest in a permanent standby unit — even a small 20 kW SDMO is a better long-term solution. No shame in portable units for short-term use, just know the limitations.

How do I choose the right SDMO generator size?

Here's a blunt answer: start with your must-run loads. List everything that absolutely needs power — sump pumps, refrigerators, lights, internet router (yes, it matters), medical equipment. Add a 25% safety margin for starting surge. Then check the generator's continuous rating, not just standby rating. A 100 kW SDMO might be rated for 100 kW standby but only 80 kW continuous. That caught me once in 2020 when I sized a 100 kW for a 75 kW continuous load — it worked, but ran hot during summer peaks. Now I always specify a generator with at least 20% headroom. And don't forget fuel consumption: a 100 kW unit at full load burns about 10 gallons of diesel per hour. If you have natural gas, that's cheaper upfront but less portable. My rule of thumb: for short outages (under 8 hours), diesel is fine. For extended outages, consider a larger fuel tank or dual-fuel option.

Still unsure? Shoot me a question — I might include it in the next update. Prices and specs change, so always verify with your local SDMO dealer before purchasing.