# Need feedback on Honda EU2000i generator box design



## xxaarraa (Apr 29, 2018)

Hello everyone,

My buddy and I are trying to engineer an enclosed generator box for a Honda EU2000i. Target use case: Pull up trackside (I race motorcycles), run generator and have full power in trailer for as long as needed. 

This means: box should be 

Sound proof
Be pre-wired with trailer power system to provide power and charge up deep cell house battery while running. 
Have enough air flow for generator to run for several hours with box closed without over heating even in Texas heat in the summer (up to 100 degree ambient air temp operating conditions)

In the design below, we have solved for 1) and 2) above. We are having a bit of trouble solving for 3). 

Here are the details of the build so far:

A) Box completely dynamatted for sound insulation, and that is working great. With generator running and lid closed, you can hardly hear anything. Generator's exhaust is routed up above trailer and has its own silencer, and the whole sound level of the setup is very acceptable. Hondas run pretty quiet to begin with and we have managed to cut the sound by another 50-60% with this setup so far. 

B) I am using a smart AC/DC distribution box inside trailer that has multiple channels and fuses to distribute power on the inside. When generator is running, the box also takes care of trickle charging the Group 31 100 AH Odyssey house battery in trailer. 

C) This is where we need some input. We have two small DC computer case fans that suck in air from the outside. I subsequently added a big AC 65 CFM fan on the intake side as well. 

We have a hole between the generator and the storage compartments, and another hole in the box in the storage compartment area to feed warm air out. Exhaust is routed separately to the outside, these holes are only for the warm air from the generator's cooling fan to exit the box. We have been experimenting with where to place the 65 cfm fan inside the box, as you can tell from the different pictures. I also took temp readings after each test run as you can tell from the photos. 

Somehow, this setup doesn't seem to be enough. I tested it yesterday in about an 85 degree day and after running for half hour, generator started sounding different and I opened the box to see some smoke. I couldn't tell if it was the fan that was smoking, or the generator itself. However, generator started back up when it cooled down and seems to be fully functional. 

Any ideas on how we could keep interior temps down to suit running generator inside closed box for extended periods? Also, what's a normal operating temp for the generator itself in hot conditions? My temp readings show as high as 230+ on the side of the generator - is that normal for the air cooled Honda?

Much appreciated, thank you,


----------



## xxaarraa (Apr 29, 2018)

OK I made some updates yesterday. 


Re-positioned the generator inside the box to ensure the rear where the generator's cooling fan was blowing hot air was closer to the second compartment and the exhaust fan. To minimize the hot air that gets blown around in the generator's own 'intake' compartment. 
Added a second dedicated 'intake fan' - I now have two identical 65 cfm fans running inside the box - one on the intake side and one for exhaust. 

Ran two tests yesterday for 35-40 minutes - one around noon and another around 5 pm - each and temps inside were a good 30-50 degrees cooler than previously. Next step is an actual field test.


----------



## drmerdp (Apr 10, 2018)

I built a generator shed for my big 7000w 5-6 years ago with great results. And from what I learned, airflow Is everything and it didn’t look like you had enough.

Second, is creating a temperature neutral space that won’t heat soak, and the dynomat being foil faced, should do the trick. The exhaust insulation is nice but it’s going to heat up the other compartment significantly. I’d rather see the exhaust fan pull air from the whole box and not just the first compartment. Do you really need to have the divide?

The 65cfm exhaust fan is likely sufficient but not with such a small inlet. The inlet size needs to be at least 3 times the size of the outlet...Unless... you Force air IN with another fan. Good Move with that.


----------

