Use of Generators

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It seems that generator-related posts come in waves, and we’ve seen just about every issue discussed. Recently, overheating was a topic of concern, but overall, generator problems are frequently brought up.

I occasionally visit Russell Coach to see what’s new and learn a bit more. During a recent chat with Rob Russell, we discussed generators. To put things in perspective, a generator issue on an entertainer coach is as critical as a heart attack—literally. On these coaches, the five or six roof air conditioners rely entirely on the generator. Rob mentioned that when a coach starts a tour, the generator is usually started right away and remains on, except for necessary maintenance like oil changes, until the tour ends.

So, what does this mean for us? The takeaway is clear: running our generators often and under load is essential. If we need to operate our roof airs or cruise airs, we shouldn’t rely on inverters or battery power alone; we should turn on the generator and run all units simultaneously. This practice ensures that our generators are exercised properly and maintained in good condition.

We used to have a habit of running the generator and loading it up when not connected to shore power, but we’ve been advised against running it with a light load. It’s worth noting that entertainer coaches often run their generators at high hours, ranging from 20,000 to over 35,000 hours. Even with a full load, a generator might not reach its maximum capacity. For example, with five roof airs, the total load might be around 75 amps on a 20KW generator, which equates to about 167 amps. This means the generator isn’t even running at 50% of its capacity, and with the AC units cycling on and off, the load decreases further.

Therefore, running the generator, even with a light load, won’t negatively impact it. By running it regularly and under load, we’re helping ensure its longevity. It’s also more convenient than managing energy while connected to shore power or running down the highway.

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Yep, that’s what Kohler told me, 35,000 hrs before even thinking about overhaul.

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When tailgating, my generator runs continuously from Friday at noon to Sunday around 1 PM—so it’s on for a solid 48 hours. With temperatures in Louisiana hitting around 90 degrees, we’re drawing about 60 amps most of the day. This gives the generator a substantial workout. Currently, with about 3,200 hours on the generator, it’s performing exceptionally well.

It’s interesting to note that in motorhome sale ads, a ’97 coach with only 500 hours on the generator is often advertised as a plus. Personally, I’d prefer a generator with higher hours. A generator that’s been used regularly and under load, like mine, typically indicates it’s in better shape compared to one with low hours that may not have been run as often or as hard.

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Hi all, don’t entertainer coaches have two generators?

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I completely agree with Jon. Operating a generator at maximum load is easier on the engine and results in better fuel efficiency per kilowatt produced.

Recently, I worked on a system design upgrade for General Dynamics, which is the prime contractor for Marine Corps combat operating bases. Each base is equipped with ten 25kW generators and ten 10-ton air conditioners. The main issue was that running these generators at light loads led to problems and increased fuel consumption. To address this, we implemented a controller that monitors all generators and ensures they operate at a minimum of 75% capacity by turning off as many units as necessary.

The challenge was integrating the three-phase generators back into the power grid and automatically synchronizing them. The reason for using ten smaller generators instead of a single 250kW unit was to keep the total weight manageable for towing by an up-armored Humvee or lifting by a small helicopter. The fuel savings from maintaining a full load operation alone paid for the modifications in under six months.

In my own case, I usually rely on inverter power as much as possible and only start the generator when needed to recharge the batteries at full load.

Regarding generator hours, a ’97 model with 500 hours might not seem low to me. When I bought my coach last year, the generator had only 219 hours. After 10 months of use, it’s only reached 340 hours.

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Hi all, don’t entertainer coaches have two generators?

Not always. It depends on the converter. On an entertainer coach, space in the bay is incredibly valuable. Adding a second generator could potentially take up space that might be more crucial for other features or amenities that the group or individual leasing or owning the coach might prioritize. If Rob Russell is around, he would be the best person to provide insight on this matter.

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Generator hours can offer some clues about a coach’s usage, but they don’t always tell the whole story. For example, a coach with low mileage but high generator hours might indicate that the owner used the generator frequently, possibly even while driving, and didn’t often stay hooked up to shore power. High generator hours on a low-mileage coach might suggest a lot of dry camping.

Conversely, low generator hours could mean the coach was mostly connected to shore power. Without additional context—like the condition of the upholstery—generator hours alone only provide part of the picture regarding a coach’s use.

Ultimately, low generator hours aren’t necessarily a positive indicator. In fact, a coach like Tuga’s with over 3,000 hours on the generator might be in better shape, suggesting it has been well-used and well-maintained.

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After experiencing a controller failure on my Kohler generator last year, I now carry a spare. I also have a 6120-watt air-cooled Yanmar diesel generator from Central Maine Diesel as a backup. I recently needed it in Louisville when the Kohler wouldn’t start due to an overheated starter or solenoid. The Yanmar burns about 0.3–0.4 gallons of fuel per hour and has a small tank, so I’m building a 4-gallon tank next week to ensure it can run all night.

One issue I’ve noticed with many generator installations is that the heat from the radiator ends up radiating under the bus, especially on those 90+ degree days. I’m considering moving the radiator to the roof to address this. With cruise airs venting hot air from their condensers and the generator radiator also expelling hot air under the coach, it can be challenging to keep the bus cool on particularly hot days.

I really appreciate the small generator at night because it’s positioned 75 feet from the bus, which means there’s no hot air being expelled underneath. As a result, when I wake up in the morning, the salon floor is cool rather than uncomfortably warm.

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Uh, Jack, you’re actually only the second POG member to use or advocate for a second generator mounted outside the coach. The other person who has done this is our very own Jeff Bayley.

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Yes, Jon, I’m aware. However, my reason for having a second generator mounted outside the coach differs from Jeff Bayley’s. I need a spare because I’ve experienced a total generator failure before, and having the spare provides a level of comfort, knowing it will help us get through almost any situation. Additionally, the spare helps address the issue of heat created by the generator under the coach, which can be problematic.

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Jack,

Are all the baffles in place? We’ve run the generator for long periods in excessive heat, and so far, so good. However, when I got my coach, the generator baffle was squashed flat, and the cross baffle for the middle two Cruise Airs was hanging on by just one bolt. I repaired both issues and make it a point to check things out regularly. I believe proper baffling is critical for effective cooling.

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Jack,

Are all the baffles in place? We’ve run the generator for long periods in excessive heat, and so far, so good. However, when I got my coach, the generator baffle was squashed flat, and the cross baffle for the middle two Cruise Airs was hanging on by just one bolt. I repaired both issues and make it a point to check things out regularly. I believe proper baffling is critical for effective cooling.

Jon, could you post pictures of those three baffles, I only have one for the OTR air.

JIM

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Yes,they are all in place.

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Jim,

I’m currently jammed up and can’t get pictures just yet, but here’s what you need to know about the baffles. You should have a steel baffle under your generator that directs exhaust air from the generator radiator towards the rear of the coach. This baffle prevents the exhaust air from returning to the radiator. Additionally, the fan that expels heat and air from the generator compartment has a small steel baffle on its exhaust to stop the air from re-entering.

In the approximate center of the second bay beneath the coach, there’s a rubber baffle (similar to a mud flap) that extends crosswise. This baffle separates the exhaust air from the two Cruise Airs in the middle of the bay, preventing it from returning to their intake. For coaches of this vintage—yours, mine, Fred’s, Tony’s, and others—all the air intakes should be protected from heated air returning to them as long as these baffles are in place.

The front Cruise Airs draw intake air from behind the bumper and exhaust it out the bottom.

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OK, I can wait.
I do have the long crosswise flap and the OTR baffle.

JIM

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