Low cost portable diesel gensets

This is a response I wrote in another forum to someone considering the purchase of a Chinese made Aurora diesel generator. I'm not all that familiar with the light duty air cooled diesel gensets, but they do outlast and outperform air cooled gasoline gensets hands down. Well, the Aurora gets pretty good reviews, and my response turned out to be a pretty fair general intro to installing and operating backup power in the context of preparedness. Enjoy.

The 3600 RPM Chinese diesel generators should (generally) outlast their gasoline powered counterparts by a wide margin, and they'll use a lot less fuel along the way. You already store diesel fuel, the price is right and you'll have a local dealer for advice and parts. Sounds good to me!

I just want people to make an educated purchase, and it's important to understand the limitations of an inexpensive (a relative term!) generator. Given your circumstances and intended use, I see nothing wrong with the one you're looking at. For a few weeks of post-hurricane grid-down living your biggest concerns will probably be maintaining communications and refrigeration, and the one you're looking at is big enough to start at least two and probably three large fridges or freezers simultaneously. It'll easily run a well pump too, if that's a consideration - just not at the same time as those three fridges! You won't even need to run it continuously - a couple hours 2 or 3 times a day should do everything you need under that scenario.

BTW, all generators are rated at sea level. Folks like me up at higher elevations need to subtract 3.5% from the rated output for every 1000 feet of elevation, and then subtract at least another 10% for density altitude on hot days just to be sure. It's much better for both generator life and power quality to run a larger generator at 80% output than to strain a smallish one at 103%!!! (This is not a concern for the unit you'll be running in Texas, but it could be critical for others reading this topic...)

You should install a manual transfer switch (big fine for electrocuting a lineman these days!) just to be sure you don't inadvertently energize the grid. This is how you'll monitor/control/alternate loads as necessary, so I much prefer transfer switches with a meter even if the generator has a meter too. Have an electrician hook it up if you have ANY doubts...

If the grid's down for a few weeks after a hurricane, plan ahead for looting. If it were me, I'd make provisions to keep it inside the garage and pipe the exhaust out through a wall or the roof. That way, it'll be less likely to go for a walk. It's going to be noisy in the garage when it's running, which could easily mask the sounds of a break-in, so I'd be inclined to beef up garage security and perhaps cement a big eye-bolt into the floor and chain the generator down as well. That way it'll stay safe even if someone gets in or your garage doors are damaged in a storm. (A lot of running generators were stolen during the big northeast ice storm that left 10 states in the dark a few years back. Clever thieves worked at night and put running lawnmowers beside the generator before stealing them so the noise stayed fairly constant and didn't alert the owners sleeping inside!) That exhaust pipe will get hot, so where you pass it through the structure, allow some clearance to combustibles and shield the hole with metal that doesn't contact the pipe. Sheet aluminum is really good for this, and the air gap is important for safety. You can secure a metal screen across the air gap with high-temp silicone but don't stuff insulation in there. (Most insulation is combustible!) If you do this think about adding an extra inline muffler to lower the noise level even further.

You'd have to spend considerably more to get a nice 1800 rpm rig or the Listeriod set-up I have, and that's just not necessary given the light duty use you have in mind. You're right about the weight, too - the cherry picker couldn't lift mine after it was mounted on it's I-beam frame - we had to use the forks on the neighbor's backhoe! When you get moved and buy a more durable unit, this one can serve as your backup.

I think the most important thing with any stand-by power source is to run it - under load - every few weeks. I've worked on a few of these units, and every facility that has backup power for critical loads performs regularly scheduled testing under load. You should too. That keeps everything in good running condition, forces you check things out regularly and builds operational familiarity. (You'll be stressed out and dealing with plenty of other problems in an emergency anyway. Knowing your power system like the back of your hand will be a godsend.)

I'd strongly suggest you put thermometers in your fridges right away and find out exactly how much run time you need to keep your food cold. (If you're not going to run A/C, keep in mind that refrigerators run longer and more frequently when they're in a hot environment. The appliance manufacturers have power usage data for different ambient temps that you'll want to find online or request.) Use the generator for this run testing, and run all the other loads as well - just as you will when the grid goes down. It'd be best to turn your main breaker off and live on generator power for a day or two right away just to test your assumptions and figure out the best way to do things. (Do this before you decide which circuits to tie the transfer switch into, using extension cords for the loads you're running.) Note your fuel consumption, adjust run time and/or run frequency for fridges in a warm house and then adjust your fuel storage accordingly. (Of course, all these part-time running calculations go out the window if you're planning to care for anyone who needs medical equipment to stay alive. Then you really need to think about fuel storage!)

On this generator the fuel tank is above the engine, and you NEVER refuel this type of generator when it's hot. The fuel consumption notes from your practice runs will tell you how often you'll need to refuel. Chart the appliance run time info and cold fueling schedule and post it on the wall by the transfer switch. A cheap wind-up oven timer is really handy to keep track of generator run time in a grid down emergency.

Use a fuel stabilizer (and I concur with the recommendation of Pri-D, the best diesel stabilizer out there) in all your stored diesel. Use the internet and the local dealer to find out what problems other owners of this generator may have had and lay in spare parts accordingly. If the alternator isn't brushless, be sure to stock some brushes and learn to change them at night with just a flashlight for illumination. I'd also figure out which synthetic oil works and after some break-in hours or at the first scheduled oil change I'd switch to that. Most likely Rotella Synthetic from your local Wally World would do fine.

This is a hair off topic, but I'd think pretty seriously about putting in a small bank of deep cycle batteries and a little modified sine wave inverter to power cellphone chargers, cordless phones, battery chargers, TV's/TV receivers and laptops/routers so your comms continue to work without running the generator full time. If you have a security system you'll want to keep that running during an emergency, too. (An LCD or LED TV is very energy efficient and this is a good excuse to get one if you don't have one yet! "We need it to monitor the news in an emergency, honey...")

For years I ran all my comm loads off batteries full-time and charged the batteries with grid power. When the grid's down, a few hours of charging twice a day should keep the batteries happy as long as you minimize use and unplug the various loads when they're not in use. (Then, as time passes, you can add a PV module or three, and a charge controller, more and bigger batteries, a sine wave inverter... It's a disease, really )

Kudos to you for making the preparations, but here's hoping you never need them!


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