Most want a generator system that is reliable over time as well as cost-effective at the time of purchase. Startup, maintenance and repair costs will affect the overall cost of a generator system and this varies tremendously between brands, engine types and fuel types (diesel, natural gas and/or propane). To help decide which type of fuel is best for a specific situation/site, please refer to this page and then read on to help decide which brand and model are best for you.

With many generators, major components are eerily similar or even identical between brands. So while a few brands will use premium engines, enclosures and/or alternators (and we applaud this), the generator's control components are commonly the biggest noticeable difference between generators, as they are rarely even similar between major brands. In fact, the quality and design of the generator's controller is usually the deciding factor in what makes one generator superior to another. That is why the generator's control components are often the most important consideration (more important than purchase price) when choosing which generator brand to purchase.

Ideally, the generator's controller and associated electronics will be open architecture, meaning that anyone can gain full access to all of the controller's programming functions. However, most larger generator original equipment manufacturers (OEMs) prefer locked, proprietary controllers with hidden functions, no publicly available documentation and limited user access in order to create a second revenue stream at your expense.

THE GRIFT is based on the Gillette razor business model, which works like this: An OEM makes it so that no one but their technicians can work on your generator's controller. Anyone who purchased from that OEM must then pay to maintain a relationship with that OEM for any startup, programming, troubleshooting, repair and/or replacement. Many find out too late that they're stuck doing business with an OEM that they can't stand, simply because there is no other option short of gutting the generator and replacing the entire controller (at significant expense). The most brazen OEMs will require special programming dongles, laptop software and passwords, which they only give out to companies that swear loyalty to only that OEM. Look around at how many local companies only offer sales of exactly one generator brand and you begin to understand how widespread this is.

If you do decide to purchase a system like this, pray that the OEM you choose will be around for as long as you own your generator (crystal ball, anyone?) because you will remain tethered to that OEM in one form or another for the life of the generator. If that's just not your style, you should consider purchasing a generator with an open architecture controller so you can maintain control of basic things like programming and maintenance.

For those in the market for new custom generators and are considering several different brands: Our advice is to specify that every field-service level of the controller's software must be accessible to you. If the controller on a generator only allows you access to a 'customer' level but making any changes or replacing the controller requires access to a level to which you will not be given access, there are three options you should consider:

  1. It is murderous to try to find a good air-cooled generator that doesn't have a proprietary controller. For those who want air-cooled, we recommend simply looking for controllers that offer the feature set you want from OEMs that don't require dealers to swear fealty to that OEM in order for the dealer to be granted access.
  2. Purchase a (possibly different brand) generator with a controller that offers full documentation and that you (or any technician you choose) can access all field-service features.
  3. Require that the generator provider give you full access to the controller (as well as all diagnostic and other manuals for the controller) for the life of the generator. Good luck with that one.

Some will suggest that it is no problem if you are on good terms with your OEM. But things change and even large companies go out of business. We see generators in the field all the time where the once-mighty manufacturer went out of business, just stopped providing generators and/or stopped supporting generators they produced in order to force you to purchase a new generator. Some examples: MTU, Coleman, Elliot-Magnetek, NorthStar, Electro-Motion, Ingersoll-Rand, SimPower, etc.

Then there is the issue of convergence. In the last few years, this has become a significant source of problems. It may be a good idea to have GPS, cameras and other various features merged into a cell phone, which most replace every year or two anyway. However, you likely wouldn't want your stove, refrigerator and toaster merged into one unit. Besides the awkward physical appearance, it doesn't make sense to merge components with completely different lifespans and costs into one unit, especially if your desire is to use each until they fail (Oh my, the toaster in my stofridgoaster shorted out again - can anyone loan me another $5,000?). Even if merging the devices saved you 30% overall when purchased, with a generator, the controllers are designed so that when one sub-component breaks you are usually stuck replacing the entire unit. While not many speak of these issues (and even fewer understand), it remains true that a generator's control components have varying lifespans, some of which are relatively short. Yet the trend with many generator OEMs has been to merge many of these separate devices (i.e. governor, voltage regulator, engine controller, battery charger) into one controller unit, presumably to save on manufacturing costs. While we applaud those seeking to lower costs, increase reliability and otherwise improve their systems, some OEMs have made it so that even a slight problem will require an expensive repair


For example, the battery charger is frequently the 'Achilles Heel' of generators, as the charger often has a short life. Say, for example, that a generator's battery charger sticks on fast charge. The charger could not stay connected and would have to be disabled/replaced to prevent the generator's battery from potentially exploding. If it were a separate component and not part of the controller, a simple replacement charger starts at under $30 at local stores and almost anyone could replace it in a few minutes. On the other hand, when the charger is integrated into the generator's controller unit, the entire controller unit may have to be replaced. In fact, to guarantee that replacement would be necessary, some OEMs will have the controller provide a constant alarm (that cannot be dismissed) when a sub-component either fails or is disabled. They do this so that there can be no work-around and a new controller (that can only be purchased at an exorbitant price from that OEM) must be purchased. Since exact replacement controller units can only be ordered through the OEM, OEMs often inflate controller prices many times over for the controller -plus- having to wait several days for it to arrive (if the OEM is still in business and if that OEM still produces it at all) -plus- several hours labor for an OEM-certified dealer with special training, laptop software, programming dongles and passwords to program your new OEM controller unit.

If the proprietary OEM controllers that came stock on major brand generators were superior, there would be a demand for them to be installed on generators to replace "aftermarket", open architecture controllers. As it turns out, we have never even heard of any generator with an aftermarket controller ever being replaced by a proprietary OEM controller. On the contrary, we have to stock many aftermarket generator controllers because we have had so many requests to have various proprietary OEM controllers from major manufacturers replaced by aftermarket controllers (i.e. Deep Sea, Dynagen, ECU). Keep in mind that, while it is relatively easy and inexpensive to specify a new generator with a quality aftermarket controller, it is always more expensive to perform this upgrade in the field. The fact that there is a significant demand for a controller upgrade service in the field, despite its relatively high cost, attests to the level of motivation some have to part ways with their proprietary (and frequently unreliable) OEM controllers.

Warranty can be another big issue. Dynagen, for example, leads the way with a generous five year warranty for their generator controllers. Contrast that with most OEM controllers, which usually carry somewhere between no warranty at all to a 90 day warranty. It is not uncommon for us to have to replace unreliable OEM controllers repeatedly, as controllers from some less reputable OEMs have a reputation for working just long enough to get past the warranty period.

Think about it this way: All the generator parts should be desirable, in and of themselves. No one wants an enclosure that is prone to falling apart. No one wants an engine that is such a lemon that the OEM almost couldn't give it away. And for the brain for the entire system, no one wants a controller that costs 2x as much, is unreliable, has a horrible warranty and forces you to forever pay to deal with the OEM that sold it to you. So then what is the best way to know whether a controller is any good? Easy: By itself, the controller should be a popular item apart from its sales with generators.

Controllers like this, that are able to be successful in aftermarket sales, have other inherent benefits besides nearly unlimited features, reliability, open access, intelligent design, quality and long warranties. Because there is competition between aftermarket controller manufacturers, their prices are also competitive, usually between $200-$400. They are often available from multiple sources, so you can choose your vendor. Lastly, because they are well documented with good installation instructions and support, aftermarket controllers are easily upgraded or otherwise exchanged for another brand, should a controller ever be discontinued. Our experience is that generators with aftermarket controllers (i.e. Deep Sea and Dynagen) are the most desirable.

While it only makes sense to purchase a generator with "aftermarket" control components pre-installed, we realize that it doesn't always make sense to upgrade existing controllers in the field from OEM to aftermarket while the OEM controller is working. The problem is that OEM controllers often fail catastrophically at inconvenient times, where the only fast way to repair the generator is to pay for the OEM's overpriced tech to install a new overpriced controller and then live with its nearly non-existent warranty. Or, if you're considering upgrading your controller, consider doing it at a time that is convenient for you. Then, you can take your time and choose the best controller for you based on its features, reliability and/or availability.

Air versus liquid cooled: We see the trends and, relative to air-cooled, liquid-cooled engines are:

  • More expensive to buy.
  • Have much more to break (radiator, water pump, hoses, coolant, freeze plugs, thermostat, etc. are all quite vulnerable).
  • Have a much higher failure rate due to coolant leaks and air gaps.
  • By far, most liquid-cooled generators ship with cheap coolant sensors that are prone to false alarms.
  • Cost much more to repair.
  • Repairs often take longer (have to source the parts).
  • Cost more to maintain than air-cooled, since you have to maintain the coolant system.
  • Conversely, air-cooled engines, relative to liquid-cooled, are:

  • Less expensive to buy.
  • Have less to break (air-cooled design is much simpler and less complicated).
  • Are more reliable.
  • Air-cooled generators generally cost less to repair and are easier to repair, should there ever be a problem.
  • Can usually be repaired much faster because their parts are more plentiful.
  • Air-cooled are the least expensive to maintain.
  • In summary, liquid-cooled generators are what you use when you absolutely can't make do with air-cooled generators. Also, those who are serious about standby power don't just have one generator - they have two or more redundant generators.

    Other recommendations: For generators, there have been relatively few products that could be considered "game changers" and/or "breakthroughs". These include: variable speed, automatic load management, digital controls (with alarm logs), remote monitoring and cost-effective paralleling. While all manufacturers offer a few of these, currently, there is only one manufacturer with offerings in all of these categories (Kohler).

    When it comes to backup power, reliability is king and, when it comes to reliability, nothing beats having a redundant (second) backup. For example, when you parallel two generators (making two generators act as one generator), you're getting a much more reliable system because, even if one generator is ever offline, you're still 50% online. Paralleled generators can also be many times more fuel-efficient under low load because they can be programmed so that one (or more) will shut down when the load is low (i.e. at night) and then come back on when the load starts to increase.

    Circling back to our air-cooled discussion: Those seeking the absolute best solution for generators in the 30-40kW range need look no further than paralleling two air-cooled 14kW or 20kW generators. Even if you only want one generator now but are considering paralleling in the future, if you purchase a generator now that can parallel, you can always upgrade to a second generator later to double your capacity without having to completely abandon your investment in your current system.

    Please keep in mind that we have techs certified on all major brand generators and their controllers including CAT, Onan, Kohler, MTU, Generac and more. Regardless of which generator you own or which controller it has, we are able to provide you with the best after-sales support. We at AAAA Generator Services Inc believe we are the best value for your startup, maintenance and service. We earn your business, year after year.