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Generac shutdown issues, help!

BrisketBiscuit
Explorer
Explorer
First post, just a quick introduction, my brother and I have a food truck called Brisket Biscuit, so not technically an RV, but I'm hoping I can get some help for a few technical issues here. We bought our trailer pre-equipped, with fridge, freezer, hood vent, water heater, water pump, warming lamp, and ceiling a/c being the main electrical draws. The generator mounted to the front of the trailer is a Generac Gp8000e, rated at 8kW continuous and 10kW surge, going through a PD4560 distribution box via a 2m 10ga 4-prong extension cord. We haven't had any issues with the unit except for the noise level, so I built an enclosure (described below). With the enclosure in place, the generator shuts down after just a few minutes, even with minimal load. Even with only the hood vent (2400W) and some led lights, it'll run for a little bit then shut down. It isn't any hotter than without the box thanks to the beefy fan, and it starts right back up, so I can't figure out what's causing the shutdown.

The enclosure is 1/2" MDF with 2mm butyl/foil sound mat inside, then 1.5" acoustic foam panels inside that on the top and long sides. The ends are pretty open, with 3x 120mm fans pushing in the intake end and a 10" radiator fan (~800cfm) pulling out the exhaust end. The exhaust itself is extended outside the box, so fumes shouldn't be an issue, though I'm not sure. The pipe turns 180 degrees and is attached to the side of the box pointing toward the intake end, but I don't think that's the issue. There are also openings for accessing the control panel and fuel filler that I keep open when running.

My next step is to change the routing of the exhaust pipe so it points down, but if that isn't the issue, does anyone have any suggestions? This thing is loud and I'm afraid it's hurting our business, and the box makes it significantly quieter, but that doesn't matter if it won't stay running.

26 REPLIES 26

MrWizard
Moderator
Moderator
"Also, what did punctuation ever do to you to deserve that kind of butchery? Still appreciate the input, but that was hard to read! Haha"

There is punctuation,
I just did not space each statement into paragraphs,
Usually i do add more spacing, but i was tired and just made one big long paragraph out of it.
Yes it could have been neater and easier to read.
I can explain it to you.
But I Can Not understand it for you !

....

Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s

Grit_dog
Nomad III
Nomad III
Good to hear. Now let’s see some of that brisket!
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

BrisketBiscuit
Explorer
Explorer
Got a quick pic today, ran another 4 hours in the sunshine with no hiccups.

way2roll
Navigator
Navigator
Glad you got it sorted out. The box looks like nice work. I love a good food truck so good luck and cheers to you!

Jeff - 2023 FR Sunseeker 2400B MBS

BrisketBiscuit
Explorer
Explorer
CA Traveler wrote:
I was wondering about air flow. Recommend 2 or 3 of the large fans on one end, no other openings on that end. large single opening on the other end and no fans. Exhaust straight up through the top and Gen-Turi to cool it.

Also have you weighed the trailer? Looks like a lot of weight on the hitch.


What hitch? The tongue is sitting on a block of wood, do you have scale-o-vision? :B but yeah, it is quite heavy. Luckily, our tow rig has the suspension and brake controls for it, though it definitely could use a few more ponies... When we can afford it.

BrisketBiscuit
Explorer
Explorer
MrWizard wrote:
The fans are wrong, blow cool air in low, remove heat up high, you are pulling the cooling air flow down under the generator and out, trapping Heat inside, also the exhaust going down is just going to rise, some of it will even get pulled back into the covering box, optimal airflow is not being met with your current design, the carburetor might be too warm, causing a vapor lock, or the generator Head getting to hot and causing the engine shut down, sound reducing boxes can work when the correct design is implemented, sound mat is a good material , foam is not, egg crate or pin cushion foam reduces air flow and holds heat, many food vendors use inverter style generators on their trailers instead of open frame generators, inverter style are enclosed are quieter when running at lessor loads, if Honda or Yamaha is outside of your budget , champion and harbor freight have inverter models that are less expensive, you obviously need electrical power so it might be wise to look into replacing the generator , if not feasible, then redesign your box put the air intake in the bottom of the box with a fan blowing in, put exhaust fans on each end of the box , this will remove more heat than a single exhaust fan mounted too low trying to pull air thru and around the generator


If you look at the box design, I did originally have the intake opening at the bottom and exhaust at the top, but I severely underestimated the airflow requirements. The big puller fan was added after the fact, and I moved the small fans up so I could reach the choke and the control panel at the same time :S

I've definitely looked at inverter generators, but with the business just getting started, it's not remotely within budget right now, so we've gotta make this work. I'm hoping to install a 48v solar system in the future, so the massive old generator can be swapped for a smaller, quieter unit.

Also, what did punctuation ever do to you to deserve that kind of butchery? :E Still appreciate the input, but that was hard to read! Haha

BrisketBiscuit
Explorer
Explorer
Thanks all for the responses. I think the issue was insufficient airflow at the intake end. It was pretty open and had the small fans, but the built-in blower wasn't flowing nearly as much as without the box. I cut out everything below the slot at the top of those fans and braced it back up with some scrap perf/slot angle. I attached a couple pieces of acoustic foam to it like curtains (so I can still reach the choke/fuel valve), and drilled a few ~2" holes on the back face. Along with changing the exhaust pipe to point up, it seems to be happy now. Ran for ~4 hours last night with no problems, hopefully it will be the same in warmer weather.

way2roll
Navigator
Navigator
CA Traveler wrote:
Grit dog wrote:
It’s not a RV so not subject to all the weird travel trailer “stuff” that virtually no one else cares about…ever, when actually using trailers.
Maybe we need the payload capacity of the tow vehicle before we can talk aboot his generator too?
Yes tow vehicle information is also needed. Weight can be a very significant factor for liability, severe accidents do happen. I wouldn't ignore it but to each his own...


Why is tow and weight information needed for this conversation?

Jeff - 2023 FR Sunseeker 2400B MBS

ScottG
Nomad
Nomad
IMHO those fans aren't even close to enough to moving enough air. If you really want some kind of fan, get a 14+" electric pusher fan (the biggest that will fit) for a vehicle radiator.

ScottG
Nomad
Nomad
Grit dog wrote:
CA Traveler wrote:


Also have you weighed the trailer? Looks like a lot of weight on the hitch.


Roflmao! Just stop…
It’s not a RV so not subject to all the weird travel trailer “stuff” that virtually no one else cares about…ever, when actually using trailers.
Maybe we need the payload capacity of the tow vehicle before we can talk aboot his generator too?


For sure a dually would solve all his problems.. 😉

joebedford
Nomad II
Nomad II
CA Traveler wrote:
Yes tow vehicle information is also needed. Weight can be a very significant factor for liability, severe accidents do happen. I wouldn't ignore it but to each his own...
I don't know how you can talk about that without knowing what kind of tires he has on his trailer.

Incidentally, I left my RV in Florida (we shall see if that's a mistake next November) and brought my "stuff" (two motorcycles, etc) home in a 16' cargo trailer. About 30km from home I noticed that the tread on one tire is "wowing" about an inch in one section of the circumference. I changed it on the spot (Walmart) but I left the other tire with wires sticking out of the tread/sidewall until I got home. I guess I'll take the opportunity to upgrade from "C" rating to "D" rating.

Oh yes, the built in Onan in my RV quits after about 20 minutes. Heat?

CA_Traveler
Explorer III
Explorer III
Grit dog wrote:
It’s not a RV so not subject to all the weird travel trailer “stuff” that virtually no one else cares about…ever, when actually using trailers.
Maybe we need the payload capacity of the tow vehicle before we can talk aboot his generator too?
Yes tow vehicle information is also needed. Weight can be a very significant factor for liability, severe accidents do happen. I wouldn't ignore it but to each his own...
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

MrWizard
Moderator
Moderator
The fans are wrong, blow cool air in low, remove heat up high, you are pulling the cooling air flow down under the generator and out, trapping Heat inside, also the exhaust going down is just going to rise, some of it will even get pulled back into the covering box, optimal airflow is not being met with your current design, the carburetor might be too warm, causing a vapor lock, or the generator Head getting to hot and causing the engine shut down, sound reducing boxes can work when the correct design is implemented, sound mat is a good material , foam is not, egg crate or pin cushion foam reduces air flow and holds heat, many food vendors use inverter style generators on their trailers instead of open frame generators, inverter style are enclosed are quieter when running at lessor loads, if Honda or Yamaha is outside of your budget , champion and harbor freight have inverter models that are less expensive, you obviously need electrical power so it might be wise to look into replacing the generator , if not feasible, then redesign your box put the air intake in the bottom of the box with a fan blowing in, put exhaust fans on each end of the box , this will remove more heat than a single exhaust fan mounted too low trying to pull air thru and around the generator
I can explain it to you.
But I Can Not understand it for you !

....

Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s

rjstractor
Nomad
Nomad
Grit dog wrote:
For the recent respondents here asking, the OP said in his first post it runs fine without the enclosure….


Sure enough, might help if I could read a little better. 🙂 Time to get a quieter generator or put up with the noise.
2017 VW Golf Alltrack
2000 Ford F250 7.3