Generator Cooling

[gus]

My genset compartment was originally poorly ventilated, don't know how it ever worked in the first place? Once I installed my 8 KW Westerbeke boat genset it would overheat and stop when the bus wasn't moving in hot weather.

I finally got the blower to my generator box installed. Next I'll wrap the huge exhaust pipe with the EHP wet blanket insulation to further cut down on the excess heat.

If none of you have ever used this wet blanket stuff you're missing out. It comes in 1/4" saturated blankets which wrap around the exhaust manifold and pipe. Once dry they become a solid heat proof cover which forces the heat out the exhaust pipe instead of overheating the genset box. I used it on the 4104 Honda genset and it worked great.

No, I have no interest in EHP - just want to share the info. However, it is expensive. $92 for a 2' x 3' blanket. To me the ease of use and results are worth it.

[rv_safetyman]

Gus, I used to sell the EHP products and they are fantastic!!!  The folks at the company are great (assuming same folks).

The wet blanket material is a bit fragile.  When I use it, I wrap it with high temperature foil tape to protect it.

Jim

[OneLapper]

Gus,

I'm in the process of designing the enclosure for my 8Kw Westerbeke.  I planned on using the only the generator head's internal fan like the factory enclosures use.

Can you describe your enclosure?

Thanks!

Mark

[TomC]

Because of space limitations, on both my bus and truck conversion, I'm using a remote mounted radiator with electric fan.  This way you can entirely enclose the generator compartment and then duct the cooling air with a fan (I use an 8" in line bathroom ventilator that flows 250cfm mainly because it is moisture resistant) blowing on the intake for the generator cooling.  Then is vented out the other side.

On my truck I'm going to use the same ventilator (at Grainger's) with longer 8" hose run to effectively quiet it down.  Then the radiator is powered with a trick 6 blade fan of low amperage made in Europe.  It makes noise on high, but with a electronic speed control, can slow it down for quiet night time use.  My goal is to have a generator that is as silent as possible.

I was at "The Rally" in Phoenix a couple of weeks ago.  Because of the speedways regulation, we were only allowed 20ft wide spaces.  Needless to say it was tight, and with being in the dry camping section (I burned 10 gallons of fuel running my generator for 5 days-alot less then the $199.00 they wanted for 30amp hookup) everyone was running their gensets.  I always worry that my genset is too noisy.  The other RV's with the "Quiet Diesels" from Onan, aren't so quiet.  With my genset running and everyone else's running, I could go outside and walk 10ft from my bus and my genset would be drowned out by the other gensets.

I once went by a buffalo 40ft'r that I was looking at.  When I felt something on my leg-and it was the genset exhaust-making zero noise!  I put my ear on the bus and could faintly hear a genset running-now that's quiet!  Good Luck, TomC

[gus]

Jim,

I use Al tape on the EHP wet blanket as the final wrap, something has to be used to protect it from vibration and oil and I don't like the clamps they sell for that purpose. I also wrap the wet insulation with masking tape to hold it together until it drys, then I wrap with the Al tape. The masking tape usually burns off, but not always. Shows how much that stuff insulates!!

To speed up the drying I usually run the gen for a couple of minutes at a time just enough to get the exhaust pipe hot, but not too hot.

Mark,

My gen box originally had two narrow slots, one near the engine cooling fan and and radiator and one at the opposite end plus a 12'x24" screened hole in the outside door of the box. This door was maybe six inches from a solid baggage door so there was no outside air source for this hole? I never understood how it cooled but it did. The PO remoted located the radiator with an electric fan which worked fine until I changed to the Westerbeke.

The Wb would not tolerate this arrangement in hot weather but worked fine in cool weather or when the bus was moving. So, I closed the outside door hole, cut a hole at the top end of the box and installed a blower I got from ebay. The blower will blow directly across the top of the gen and exhaust manifold. I think it is something like 245 CFM and draws 0.95 amps. To feed cool air to this blower I have three appx 3" diameter holes that were already cut into the floor.

So, the cooling air comes from these holes ahead of the gen box into the blower and hot air from the gen is forced out the bottom of the gen box. Not ideal but the only sensible physical way I could do it. Since the intake holes are already there I chose to use them instead of cutting holes in the baggage door.

Ideally the cooling air should come in from the bottom and the hot air exhaust out the top but I couldn't do that without cutting holes in the bag door. However, since the blower will pressurize the gen box I think this system will work well plus the gen exhaust pipe goes through one of the two bottom box holes so the outgoing air will help cool that also.

In addition to this I will wrap the exhaust manifold and pipe with the EHP wet blanket insulation. This should eliminate about 80% of the heat now going into the heat box. I may not even have needed the blower with this insulation but it is already installed and didn't cost much plus a few hours labor. It is on a separate switch so I can cut it off when not needed. It provides peace-of-mind!

The 4104 genset installation was so simple because it used the old original bus AC compressor engine compartment which already had a screened door and open bottom.