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Discussion Starter · #1 · (Edited)
Hey folks, I built an enclosure for my generator and propane tanks and wanted to share and get some feedback! It's a stud built structure, 3/4" plywood sheathing on the outside with 1/2" cement board on the inside (walls and ceiling) and covered inside and outside with stucco. It's open to the front with a 14" overhang so even in some pretty heavy rain water doesn't get inside. The open side of the enclosure faces the house so rain generally doesn't come from that direction

I didn't want to enclose the structure since I'm storing propane inside and being enclosed I would have to deal with ventilating the heat and exhaust. I did add an 800 cfm exhaust fan to keep the air moving. Thinking back on it I don't think 800cfm will do much but this model fan fit between 16" OC studs so I threw it in there. I don't imagine I'll have much heat issues with the front being open. I'll monitor it when I break in the generator and if I need more airflow I'll mount a box fan behind the generator or something.

A lot of people go with those plastic sheds but I live in area that gets hurricanes so I wanted something more stout. I initially was going to build the structure out of concrete block but after hauling 25+ 80lb bags of concrete for the pad I had no desire to deal with blocks and grout fill. I used all pressure treated lumber in the framing.

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I installed a 10w solar panel with a built-in trickle charger to keep the battery topped off.

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The generator I'm using is dual fuel and I will be primarily be using it with propane, I have 4x 40lb tanks. I took the idea of using a manifold for the propane tanks from someone online. I put a regulator on each tank to keep the pressure low in the hoses and manifold, I could probably have just used one regulator but this way seemed safer. The manifold is nice because it will allow me to hot swap tanks.

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I went with the DuroMax XP9000iH since it's the largest inverter on the market as well as dual fuel and remote start. 7,200 running watts on propane and 7,600 on gasoline. I wanted to be able to remote start the generator in the case of inclement weather.

Something I didn't think of is the load the electronics will put on the battery when leaving the "start up" switch on 24/7 so I can remote start it at will. I will have to monitor battery voltage to see if the 10w solar panel can keep it topped up. If not I will switch to a 50w solar panel/charge controller.

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I relocated the 30-amp inlet box into the enclosure (and yes I need to put a strap on the conduit!).
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A few things:

1. The shed and propane tank configuration is great
2. The exhaust fan is a little too small and placed in a less-than-ideal location. It should be placed in a way that will promote airflow to go through the full cross section of the generator. In your case, it might be better if it's installed at the back wall behind the gen, so cool air from the front will pass the generator, expelling the hot air to the rear of the shed
3. I don't think you should leave the system power turned on (for the remote to work) indefinitely. I think they're meant for short-term and/or frequent start/stop operation, like at a construction or camp site
4. Somewhat inline with #3, I don't think it's designed so that the propane can be left turned on when the gen is not in use. The demand regulator for these portable gens are likely not designed to hold off propane indefinitely.

Just my 2c.
 

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Discussion Starter · #3 ·
A few things:

1. The shed and propane tank configuration is great
2. The exhaust fan is a little too small and placed in a less-than-ideal location. It should be placed in a way that will promote airflow to go through the full cross section of the generator. In your case, it might be better if it's installed at the back wall behind the gen, so cool air from the front will pass the generator, expelling the hot air to the rear of the shed
3. I don't think you should leave the system power turned on (for the remote to work) indefinitely. I think they're meant for short-term and/or frequent start/stop operation, like at a construction or camp site
4. Somewhat inline with #3, I don't think it's designed so that the propane can be left turned on when the gen is not in use. The demand regulator for these portable gens are likely not designed to hold off propane indefinitely.

Just my 2c.
Ventilation is definitely something I will have to play with. The fan is pretty close to where the exhaust is, depending how far back I put the generator in the enclosure.

I would love to hear from some people who have a similar set up and if they leave the electronics and propane connected 24/7. I don't frequently have power outages, I could turn off the ball valve supply to the generator and the process would be just to flip the main switch on the generator and the gas ball valve.
 

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i would have build another structure out of block next to it for the LP.

lp tanks get hot and try to vent sometimes...

also they make 12 volt LP valves...
if you had a valve cracker then the lp could be called for when you call for start.
 

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The fan is pretty close to where the exhaust is
I know you mentioned that you did not want to consider running the exhaust thru the wall. However, there are several reasons to do that...

1. These gens have very high CO output...much more than a car per gallon of gas. Operating an average portable gasoline generator (~3.5 hp) at an average load of 1.8 kW for 1 hour emits as much smog-forming pollution as driving an average car for about 150 miles. Propane has about 1/2 the CO of gasoline, but it is still very high. The exhaust from a propane gen smells less than a gasoline unit, so you may feel safer being in the shed with the gen running. The reduced odor gives a false sense of security.
2. Even though the shed is open, the gen may shutdown due to CO buildup in the shed on a very still day. It would just depend upon how much forced air flow you are providing with the fan...it may be enough, or maybe not.
3. Much less heating in the shed as the hot exhaust will be vented directly outside. Your existing fan may be sufficient CFM if not having to deal with the exhaust heat.
4. Much less noise inside the shed if you are in there working while gen is running.
5. Probably less noise outside the shed if you do a vertical exhaust (the noise will be direct to the sky). If you need ideas on how to do that, we can help.

As for the 10W solar panel, my gut tells me that it is not enough. You could measure the current draw amperage by disconnecting the battery and putting your meter inline, then turn the key on. Calculate the watts and go with a solar panel that is about 4-5 times that wattage minimum.

I do not know the ramifications of leaving the key on. You might want to call customer support about that.

Definitely do not rely upon the demand valve to prevent gas flow/leakage when the gen is not in use. You need a solenoid operated valve for that if you want the remote start capability. It is best that the LP is shut off at the source (the manifold) when the gen is not running.

i would have build another structure out of block next to it for the LP.
You could build a partition down the center of the shed to separate the LP from the gen. It looks like you have the room especially if you turn the gen sideways.
 

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Discussion Starter · #6 ·
I know you mentioned that you did not want to consider running the exhaust thru the wall. However, there are several reasons to do that...

1. These gens have very high CO output...much more than a car per gallon of gas. Operating an average portable gasoline generator (~3.5 hp) at an average load of 1.8 kW for 1 hour emits as much smog-forming pollution as driving an average car for about 150 miles. Propane has about 1/2 the CO of gasoline, but it is still very high. The exhaust from a propane gen smells less than a gasoline unit, so you may feel safer being in the shed with the gen running. The reduced odor gives a false sense of security.
2. Even though the shed is open, the gen may shutdown due to CO buildup in the shed on a very still day. It would just depend upon how much forced air flow you are providing with the fan...it may be enough, or maybe not.
3. Much less heating in the shed as the hot exhaust will be vented directly outside. Your existing fan may be sufficient CFM if not having to deal with the exhaust heat.
4. Much less noise inside the shed if you are in there working while gen is running.
5. Probably less noise outside the shed if you do a vertical exhaust (the noise will be direct to the sky). If you need ideas on how to do that, we can help.

As for the 10W solar panel, my gut tells me that it is not enough. You could measure the current draw amperage by disconnecting the battery and putting your meter inline, then turn the key on. Calculate the watts and go with a solar panel that is about 4-5 times that wattage minimum.

I do not know the ramifications of leaving the key on. You might want to call customer support about that.

Definitely do not rely upon the demand valve to prevent gas flow/leakage when the gen is not in use. You need a solenoid operated valve for that if you want the remote start capability. It is best that the LP is shut off at the source (the manifold) when the gen is not running.


You could build a partition down the center of the shed to separate the LP from the gen. It looks like you have the room especially if you turn the gen sideways.
I'm actually open to running the exhaust through the wall. I'm looking at some 1" double wall exhaust tubing or perhaps 1.5" with a 1" reducer to connect to the pipe. I would want to make it easy to disconnect so I can move the generator around to service it. I'm interested in seeing a setup where the exhaust points to the sky and what hardware people are using.

I might just leave the system off until I think I might need it. It is very rare for me to lose power, this setup is mostly for hurricanes. I use an NC gas solenoid for my built-in BBQ, so I am familiar with that setup. Unfortunately I don't have power nearby the generator shed, and it was a pain to bring in the inlet feed conductors as I had to go under a bunch of concrete.
 

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I don't have power nearby the generator shed, and it was a pain to bring in the inlet feed conductors as I had to go under a bunch of concrete.
If you have conduit between house and shed for your gen feeds, then you could run 120V power for an outlet out to the shed in the same conduit. You could also run control wires in the same conduit if needed. Conduit fill rules would apply, and the wire would need to be appropriately rated (wire size and insulation) and meet local code. Just pull out your existing wires and then pull them back in with the added wiring.

I'm interested in seeing a setup where the exhaust points to the sky and what hardware people are using.
One of the simplest "skyward" exhaust setups that I have seen is using a single straight piece of metal emt electrical conduit (or use standard galv pipe) and electrical mounting brackets with a flex exhaust from the gen run about 12-18" inside the bottom. If the conduit (or pipe) is oversized the gen exhaust will create a venturi type effect and draw cool air from bottom. No rain cap is needed as water will simply run out the open bottom. Just pull the flex exhaust out of the pipe if it helps when servicing the gen. I am not a fan of the silicone exhaust piping, but the stainless-steel flex exhaust seems to work well. I would use exhaust wrap on the part inside the shed including where it goes thru the wall. Also, I would use an additional metal sleeve outside of the wrapped exhaust pipe (or even double wall) thru the wall.
If you run the exhaust pipe very far, it needs to be oversized so as to not introduce back pressure for the gen. And avoid any sharp bends in the exhaust as well.
 

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Nice shed, but, move the tanks into a separate area.

Propane is heavier than air. You're probably thinking it will just "flow out" the open door if there is a leak, or from a tank overheating and venting.
A leak could release almost 300 cu ft of vapor from a single 40# tank. That's not just going to cause a fire but think explosion if there's a source of ignition. Then there's still the other 120 pounds of propane and gasoline in there.

You only need a 2-10% mixture. You may/may not smell it.

We use propane as a fuel source in aircraft firefighting. The flame spread is about 900' a minute. You won't have time to do anything.

I use propane with my generators too. But, the tanks are more than 20' away.

Just my two cents.
 

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Adding a propane leak detector wouldn't be a bad idea. Mount low for propane. Something like this...

I would partition the shed and put the fan at the back of the gen side blowing air inward and out the front of the shed. It will require a change of louvers because the fan would no longer be able to open them of course.
 

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Discussion Starter · #11 · (Edited)
Great feedback from everyone. The next thing I'm going to work on is venting the exhaust outside of the enclosure. It looks like it should be pretty easy to do, the spark arrestor comes out easily (is that what you call the end piece? there is a spark arrestor inserted into the exhaust pipe too).

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I'll have to think about the propane storage a bit more. I could relocate the tanks behind the structure and plumb it through the wall with a shut off valve on the interior side. Would take a bit of work to extend the roof to keep them dry. Thinking maybe adding passive vents low on the wall, or maybe build a box around the propane tanks and have it vented straight outside similar to how a marine propane locker is designed.

Question: If you have a floating neutral generator, should you do anything special for the items you have plugged into the 120v receptacles?
 

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Question: If you have a floating neutral generator, should you do anything special for the items you have plugged into the 120v receptacles?
Do you mean at the generator, or at the house?

The one thing you do need to consider is that you should only have one neutral-ground bond in the system. So, if you are tying into your house panel the N-G bond would be there and the generator would not have a N-G bond...it would be floating.
 

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Discussion Starter · #13 ·
Do you mean at the generator, or at the house?

The one thing you do need to consider is that you should only have one neutral-ground bond in the system. So, if you are tying into your house panel the N-G bond would be there and the generator would not have a N-G bond...it would be floating.
At the generator. I've removed the N-G bond in the generator. The only N-G bond is in my main panel, I have a transfer sub-panel and N-G are not bonded there. If I have the generator hooked up to my house, are the receptacles on the generator itself safe to use? I'm reading a lot of conflicting information about generators with floating neutrals and safety of the generator receptacles.
 

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If I have the generator hooked up to my house, are the receptacles on the generator itself safe to use?
They are absolutely safe. When hooked up to the house, the N-G bond is restored to the generator as it was before.

If you are running the gen without being hooked up to the house and you want to restore the N-G bond temporarily, then make a N-G bonding plug. You can plug it in to make the bond, and then unplug to break the bond as necessary.
 

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Oh, and personally I wouldn't overthink the propane tank thing. There are thousands of people running gens with the tanks in the same shed. In fact, in cold areas they direct the gen exhaust onto the tanks to heat them. You haven't said, but I suspect you are not in a cold climate area based on what you have built. Take the normal (not extreme) precautions with the tanks and you should be fine IMHO.
 

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Discussion Starter · #16 ·
They are absolutely safe. When hooked up to the house, the N-G bond is restored to the generator as it was before.

If you are running the gen without being hooked up to the house and you want to restore the N-G bond temporarily, then make a N-G bonding plug. You can plug it in to make the bond, and then unplug to break the bond as necessary.
Thanks! I ordered a plug end to create an N-G bonding plug to keep on hand for those occasions.

Oh, and personally I wouldn't overthink the propane tank thing. There are thousands of people running gens with the tanks in the same shed. In fact, in cold areas they direct the gen exhaust onto the tanks to heat them. You haven't said, but I suspect you are not in a cold climate area based on what you have built. Take the normal (not extreme) precautions with the tanks and you should be fine IMHO.
I'm in Florida and we rarely see temps below 45F where I am. I've leak tested everything so far with a handheld combustible gas detector and all good. I'll probably install a gas detector and maybe consider adding a little bit of extra ventilation. I totally understand the concern people have, I built an outdoor kitchen a few years ago and was extra cautious - the propane tanks are outside the cabinetry in open air, the gas line is controlled by a solenoid valve and the cabinetry has passive vents and a 240cfm fan ventilating the cabinet. I probably would have done a bit more here but I don't have 120v power nearby and didn't want to run it.
 

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Sigh. :( I just have to rant about something...

I just pulled up the manual for the XP9000iH and once again I find that there is no wiring diagram, parts list, or break-in procedure. All 3 should be provided to the buyer IMHO. The DuroMax is a good gen, but would it hurt them to provide that info? Actually, it might because they get to sell more replacement generators that way. I wouldn't expect a service manual to be included...that's different.

My Champion has all of that in the owner manual. Another example is WEN which provides the info (sometimes in separate downloads, but that's not a big deal...at least it is provided).

This guy agrees about the missing parts & wiring info, and he ended up returning the gen because he only got the runaround from DuroMax...

 

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^ Fully agree, 100%.

Although at a slight tangent, the Right-to-Repair movement seeks to make such things like diagrams, parts, and tools available to consumers and 3rd-party repair outfits. I am old enough to remember that schematic diagrams were often printed or stickered behind or inside appliance cabinets. Any technician worth his salt will be able to study it and effect repairs using standard tools and off-the-shelf parts.

Nowadays, a great deal of parts are proprietary and some go as far as bricking the product if you replace something, even if it's a genuine replacement part from, say, a donor unit (think Apple products, et al.)
 
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