Portable Generator choice

[JimPghPA]

There are also the hidden cost to consider.

You MUST keep the genset far from the house to avoid carbon monoxide poisoning, and with the racket it will make you will not want it close. You will require a heavy wire gauge cord from the genset to the house, and connectors on that cord.

You will want to get a heavy chain and a heavy lock to lock it to a tree or some other well established in ground anchor. Generators are a high theft item during an outage.

You will require many plastic gas cans. If you do not want to lift heavy weight go with 2 and a half gallon cans. If you can easily lift 5 gallon cans go with them. I have 22 two and a half gallon cans. You have to rotate stock. You will require a gas funnel to put the fuel in your car.

You will require some means to connect the power to the house. A transfer switch can be found on e-bay sometimes. I got a good new one for $114 on e-bay, but you could spend as much as $400 for one. Add about another $60 to $90 for the male outside generator plug and box. More wire from the male outside box to the transfer switch.

You will require a stock of oil, a small thin oil funnel ($1 at wall-mart), a big gas funnel (pep-boys) (cut the bottom off of a fuel funnel so it sits well in the gas tank of the generator, spare spark-plugs, gap setter, hearing protection, a couple of tool boxes to put it all in, Sta-Bil fuel treatment, Sta-Bil spray foaming after-run oil, spark-plug socket, cheap ratchet, an extension, a spare air-filter, a hand siphon pump to drain generators gas, a tarp to protect generator from rain, rope for tarp, pools if required to support the tarp (I use the big swing set we have), and a couple of flashlights.

Some people use a back feed to a dryer plug, or add an outside 220 plug to the 220 line on the AC. These kind of connections use what is commonly called a suicide cord, because they make a cord that has two male ends, and if someone who does not know what they are doing uses it they can kill them self. Not to mention the problem of not having a transfer switch to isolate the main feed from the neighborhood. Usually if you try to power the main feed of a house by not properly using a transfer switch you will be trying to power the whole neighborhood, and that is so much load that it is like a giant short to your genset. It either trips the circuit breaker or burns out the genset. And there is the danger of causing power on power lines that are thought to be dead, and possibly killing some lineman who is working on them.

If you use a suicide cord, and someone visits you during a long outage, they may end up being the one who gets killed, because they do not know what it is. A good example is powering a small trailer home with a double male cord. Someone may visit while the person who runs the genset is not around, and pull the cord for some reason.

There was a video on ElectricGeneratorsDirect where someone turned on the main power while a genset was on the house power. The genset electric section went up in flames. The flames ignited the gas tank, the gas ran on the ground and took out a mobile home parked next to it.

If you go with the big natural gas unit, you might require a ditch be dug, for the gas line. Sometimes the gas line to the house is too small, and a larger line must be put in. That usually requires digging up the front of the house. You will require a cement pad for the generator, a transfer switch and wiring.

Any way you look at it, the generator is not all of the cost of adding a backup power system for your house. Often the additional items add up to more than the cost of the genset.

 

[raffy]

As Scott and Jim pointed out, there's a lot to consider! Another option for infrequent outages is to run dedicated cables into your house for the generator that are completely separate from your regular household power. During the tornado outage here in AL, I simply ran orange extension cords from outside to inside the house under the back door. They fit perfectly under the door and it was still easy to open the back door when needed. I ran one which served the fridge and attached a three outlet extension cord to it to also serve a light and to recharge cell phones and the like. The other went to the computer, wireless router, etc. which were already connected to a power strip.

I used a Kill-a-Watt meter to measure the power draw of these items during use and conbined they were about 500 W or a little less, which was one-quarter of the maximum capability of the EU-2000i, or less than one-third of its maximum sustained output capability. The only time the generator would surge was when the fridge motor started up - no problem for the generator.

The main disadvantage of this approach is that there were extension cords running to various parts of the house, and these were tripping hazards. But for a short term power outage of 4 days, this was just fine for us. Some advantages are no transfer switch needed, no "suicide" cord needed, and no risk of blowing up your generator should the main power come back on suddenly. Of course, hooking up a transfer switch will work with an inverter generator also, but it is an added expense.

As I said before, the portability of these units is like gold to me! It is easy to move them around and avoids the hassle of trying to wheel a heavy conventional genset through a grassy yard and/or being forced to leave it exposed to the elements. The portability of our EU-2000i makes it easy to change the oil, remove excess fuel, and drain fuel out of the carburetor for long term storage. We keep ours in the garage or in the shed (with no fuel in it) so it is stored away from the elements. And its quietness makes it less likely to be stolen during a power outage because they're less likely to be heard!

Bottom line is, you'll have to decide what factors (cost, portability, quietness, convenience, etc.) are most important to you and then make your decision.

 

[Cujet]

Originally Posted By: JimPghPA
There are also the hidden cost to consider.

You MUST keep the genset far from the house to avoid carbon monoxide poisoning, and with the racket it will make you will not want it close. You will require a heavy wire gauge cord from the genset to the house, and connectors on that cord.

You will want to get a heavy chain and a heavy lock to lock it to a tree or some other well established in ground anchor. Generators are a high theft item during an outage.

You will require many plastic gas cans. If you do not want to lift heavy weight go with 2 and a half gallon cans. If you can easily lift 5 gallon cans go with them. I have 22 two and a half gallon cans. You have to rotate stock. You will require a gas funnel to put the fuel in your car.

You will require some means to connect the power to the house. A transfer switch can be found on e-bay sometimes. I got a good new one for $114 on e-bay, but you could spend as much as $400 for one. Add about another $60 to $90 for the male outside generator plug and box. More wire from the male outside box to the transfer switch.

You will require a stock of oil, a small thin oil funnel ($1 at wall-mart), a big gas funnel (pep-boys) (cut the bottom off of a fuel funnel so it sits well in the gas tank of the generator, spare spark-plugs, gap setter, hearing protection, a couple of tool boxes to put it all in, Sta-Bil fuel treatment, Sta-Bil spray foaming after-run oil, spark-plug socket, cheap ratchet, an extension, a spare air-filter, a hand siphon pump to drain generators gas, a tarp to protect generator from rain, rope for tarp, pools if required to support the tarp (I use the big swing set we have), and a couple of flashlights.

Some people use a back feed to a dryer plug, or add an outside 220 plug to the 220 line on the AC. These kind of connections use what is commonly called a suicide cord, because they make a cord that has two male ends, and if someone who does not know what they are doing uses it they can kill them self. Not to mention the problem of not having a transfer switch to isolate the main feed from the neighborhood. Usually if you try to power the main feed of a house by not properly using a transfer switch you will be trying to power the whole neighborhood, and that is so much load that it is like a giant short to your genset. It either trips the circuit breaker or burns out the genset. And there is the danger of causing power on power lines that are thought to be dead, and possibly killing some lineman who is working on them.

If you use a suicide cord, and someone visits you during a long outage, they may end up being the one who gets killed, because they do not know what it is. A good example is powering a small trailer home with a double male cord. Someone may visit while the person who runs the genset is not around, and pull the cord for some reason.

There was a video on ElectricGeneratorsDirect where someone turned on the main power while a genset was on the house power. The genset electric section went up in flames. The flames ignited the gas tank, the gas ran on the ground and took out a mobile home parked next to it.

If you go with the big natural gas unit, you might require a ditch be dug, for the gas line. Sometimes the gas line to the house is too small, and a larger line must be put in. That usually requires digging up the front of the house. You will require a cement pad for the generator, a transfer switch and wiring.

Any way you look at it, the generator is not all of the cost of adding a backup power system for your house. Often the additional items add up to more than the cost of the genset.


Very well said. I made every effort to keep costs down and simplicity up.

I spec'd out a small generator CB box and connector outside the garage. So, I have an approved, simple way to power the entire house. With 2 different generator receptacles. I don't move the generator far from the house for security reasons. I simply pull it in the garage when I leave the home (off, of course).

In my case, I did not opt for an expensive "transfer switch" that only runs "certain" circuits. I can power the entire house and I manage power by turning things off. Very simple and effective.

 

[engineerscott]

Let me second the motion for the Kill-a-Watt plug in meter. Those things are invaluable for checking out the load demands of common household appliances, and they're not that expensive ($30ish last time I checked). They will give you instant information on steady-state power, line voltage, and frequency. Mine doesn't sample fast enough to give a great deal of insight into startup power, but it's still worth the price. I would do what Raffy suggest, buy a Kill-a-Watt and use it to look at the power requirements of the appliances you want to run. Make sure that when you're looking a refrigerators and freezers that you capture the power with the compressor both on and off. When you're done it, you can install it on the feed out of your generator if you have a smaller gen that won't exceed the max current rating on the Kill-a-Watt (which is 15A I believe) and you're only doing 120VAC (not 240). I would not recommend plugging it directly into the outlet on the generator, as the vibration might shake a solder joint loose. On my smaller gen, I plug a short extension cord into the gen and plug the Kill-a-Watt in that cord, and then plug a power strip into the Kill-a-Watt which is inside the house. Gives you a convenient way to monition the total power load from inside the house.

BTW, I also used mine to fine tune the governor to get as close to 60Hz as possible. It wasn't that far off (~58Hz if I recall).

 

[opepat]

Raffy and Engineer Scott, excellent suggestion on the Kill-A-Watt meter. This should clarify the power needs. Thank you JimPghPA for the safety requirements. When we built our electrician installed the panel with the generator supply switch and had a 30 amp receptacle installed behind our garage for a portable generator. I found a 10 ft 10 gauge cord rated for 30 amps and UL listed.

 

[raffy]

One thing to remember that I didn't mention earlier about using the Kill-a-Watt or similar power meter is that generator power, at least for inverter generators, is given in peak volts times peak current, or what is referred to as VA on the Kill-a-Watt meter. This is NOT the same as the average power usage which is what your power company uses to measure, and bill you for, your monthly energy use. Those of you who have studied advanced math (having to do with sine functions and phases of voltage and current) will know what I'm talking about here; if not, don't worry about it but be sure to use the VA setting on your meter to measure the power draw of each item you want the generator to power and make sure that the sum total is less than the rated wattage of your generator. Using the average power will give you a deceptively low power reading and you may overload your generator!

 

[meep]

ooooo here we go....

you are speaking of power factor, yes?

I have a rudimentary understanding at this point, but wouldn't this apply to standard copper-coil gensets too?

M

 

[raffy]

Yes, power factor is the issue! I'm no expert on this myself, but this would also apply to conventional non-inverter gensets as well. But not owning one myself, I'm not sure how the typical conventional genset manufacturer reckons power. I suspect they also use peak volts-amperes (VA) to calulate their power, but am not sure.

I know that the Honda EU-2000i, which is what we have, uses VA for advertising its power (as it says so in the manual). So the actual average power wattage that it is capable of putting out is less than the VA power (usually the power factor is around 0.7 so multiply the VA by that and that will give you your actual average power). For the EU-2000i, sustained VA power is 1600 watts; with a PF of 0.7 that is 1120 watts average. Quite a bit of difference there, eh?

As long as you're consistent in measuring your loads by the same method the manufacturer uses in reckoning generator power, you'll be OK. You'll have to check your manual to verify which power method your generator uses.

 

[GeneralEclectic]

The manual for my Honda ES6500 spends all of one sentence discussing power rating. 6000VA continuous, 6500VA 30-minute intermittent. That's VA, not watts. They make no mention of maximum current except for the main breaker which is 30A. That puts a tight limit on power factor close to full load, since voltage is actively regulated at 120/240VAC which implies a full-load current of 27A maximum on either leg.

Even if you're using an inverter type of generator, you'd still need to worry about total VA, since the inverter's semiconductor output devices are rated for total current. They don't see or care about power factor, only the current they're being asked to deliver.

Therefore, when you're surveying your loads with the Kill-A-Watt, VA is a more conservative measure of calculation. Unless, that is, if you happen to know that some of your loads are capacitive (highly unlikely) and would offset the typical lagging power factor of everything else.

And to complicate things further, if your loads happen to include a high percentage of electronics (those without PFC-correcting supplies) you will have highly nonlinear current draw on those, that will further screw up your estimates. While the K-A-W will give you a power draw (which will be accurate) the power factor and VA it computes will be misleading due to the nonlinear nature of the current waveform. Power factor, as a number, is meaningful only for waveforms with low "normal" harmonic content. When you get into spiky currents as you find with typical electronic power supplies (including things like microwave ovens) then you're off into a gray area. You can safely assume that either generator type, conventional or inverter, doesn't like those waveforms at all and the true VA output under those conditions will be lower than the rating for conventional sinusoidal current waveforms.

 

[engineerscott]

Yep. Real power (i.e. what the power company bills you for ) is I*V*cos(theta), where theta is the phase angle between voltage and current. Reactive power (which is due to currents that circulate between the load and the source which are out of phase with the voltage) is I*V*sin(theta). Real power is given in units of Watts and Reactive power is given in units of VARs (Volt Amps Reactive). Cos(theta) is "power factor) and varies ideally from zero (i.e. for a purely reactive load where the voltage and current are completely out of phase) to 1 (for a load that is purely resistive and the voltage and current are completely in phase). Real world loads will never be purely resistive or reactive but instead a combination of the two, but will often times be dominated by real or reactive components.

All this talk about power factor and phase angles though inherently assumes that the load is linear, i.e that the load current is essentially a sinusoid (regardless of the phase angle). Back in the dark ages when most loads were incandescent lamps, heating elements, or motors this assumption was by in large valid. Today, with solid state electronics and offline switching power supplies this is no longer as true as it once was, as many of these devices have highly non-linear current demands (though larger switching power supplies are regulated by government agencies to the point where their current demands are "mostly" linear). Power factor is more difficult to discuss in a meaning way with many modern electronic loads.

Raffy is absolutely correct though that what your generator generally cares about is "Complex Power" which is simply V*I (which disregards phase angle and power factor completely). Units of Complex Power are simply VA (Volt Amps). While only Real Power causes work to be done on the load, both real and reactive currents cause I^2*R losses in the generator which causes heating to occur, and often times generators are limited by thermal heating of the generator windings. The Kill-a-Watt will display both load current and voltage and I believe that the current displayed is total current (i.e. not just real current), so just multiply the two to get the VA of your load.

BTW, most major appliances will have power factors around 0.9 (i.e. Real Power ~= 0.9 * Complex Power), so for those loads you can generally just use the real power numbers that the Kill-a-Watt gives you. If you want a little margin add ~10% to the Kill-a-Watt measured power. The only significant load that I've seen that had very low power factor were some very old desktops and laptop power supplies. These loads are generally low enough that they don't matter so much to your total power calculation, and modern desktops and laptops are regulated by the government to have better power factors (above 0.85 or 0.90 I think, haven't looked at that spec lately). The other thing that might give me some concern would be the florescent "worm bulbs". These are supposed to fall under the same guidelines and must have reasonable power factors to be sold, but given the price pressures and where these are being made, I wouldn't be surprised if some weren't being sold without power factor correction circuitry. But, once again unless you're running a lot of them it may not be a huge issue. I have heard that some florescent worm bulbs have caused some overcurrent tripping issues on inverter-generator type gens.

 

[JimPghPA]

Resistive heaters will have a power factor very close to 1. The resistive heater is probably something like 0.99, and then you have the fan. The fan is going to be very low, but probably draws something like 60 Watts, so it is not a large percent of the total load.

GeneralEclectic brings up a very important point about not exceeding 27 Amps for either 120 Volt sides of the 240 Volts.

I used the circuit breaker locations along with knowledge of how the bus bar in the main box feeds the breakers, and put a blue or red dot on each plug in the house so I can determine the side of the 240 that each 120 Volt plug is on by looking at the plug. This way I can add up each sides load and be sure both sides are not overloaded. The main reason I did this was in case I had to use the big 240 Volt generator to run resistive heaters.

I have enough resistive heaters (14) to heat the house if the furnace dies, but know that I would be very limited if I had to run them from the big genset. Low is 1000 watts, high is 1500 watts on these little 13 dollar Wall-Mart resistive heaters. One larger Wall-Mart quiet resistive heater we have draws 1100 Watts on Low, and 1310 Watts on High.

I did have to use them one winter for a few day when the furnace heat exchanger leaked, and the carbon monoxide meter showed low levels. The heat exchanger was replaced under warranty, and with the resistive heaters the house (except for the cellar), was at normal temperature.

Ps; When I use the 2000 watt inverter to run the house, I have a plug that ties both sides of the 240, and only 120 Volt outlets are usable.

 

[JimPghPA]

Most of the larger gensets that are not inverter, have plastic on the electric generation side farthest from the engine. This plastic can get too hot if you run the genset near maximum for too long on a warm or hot day. If it get too hot it will warp, and be useless. So on hot days, be sure to derate the maximum continuous load, or you could warp this plastic end. Also, there is a bearing in there that requires grease (Kendal red wheel bearing grease is what a local generator repair person recommended) every couple of years.

 

[Clevy]

I am a custom home builder and my generator runs 11 hours a day 6 days a week. I have learned from experience that If you are buying portable equipment it's gotta have a Honda motor. I make my living with my gas powered air compressor and generator. Honda. They are expensive but worth every penny

 

[GeneralEclectic]

The Sawafuji generator in the ES6500 has an aluminum casting on the non-engine end to support the rotor shaft bearing and the exciter/regulator. But it's always good advice to follow temperature/load limits from the manufacturer, if they bother to make that information available.

I just surveyed a couple of Harbor Freight user manuals for generators and there's not a word about load rating v. ambient temperature, nor is there for the ES6500. It's probably a reasonable assumption that on any generator there's some point at which you need to derate the capacity due to high temperature operation. Looks like either they don't think it's an issue due to their extremely conservative design margins (haha), they never bothered to estimate/measure/test performance in ambient extremes, or they simply don't want to tell anyone because it would be a reason to buy from someone else.

I'd be VERY cautious about high temperature operation with an inverter type, compared to a conventional generator.

 

[meep]

^^^ may vary per model??

the eu2000i I used to own had seriously massive airflow... fresh air first hits the electronics then the engine. It moved TONS of air and IIRC seemed to rely on thermal protection internally more than current-sensing (as it would allow you to run it above its listed maximum for short bursts). I actually worried that the engine would run below optimal temps under light winter loads.... air temps on the exit end were perceivably ~90F during the winter. If it was running hard, it would melt the snow, ice, and then completely dry the deck about 4-5' behind it, 2' wide...

The yamaha I use now circulates less air, though the electronics appear to be mounted in a more massive metal casing. I don't have much of a feel for it yet.

 

[h8snow]

I have had much trouble with my EU2000 freezing up the carb running at temps -5 and below. Talked to several dealers around this area said to cover air intake for cooling. Wish could come up heated carb for this model.

 

[Digital2k2]

Do you guys that have or had the honda eu2000i stick to the 200 hour or once a year valve adjustment? I watched a video on how to do it and it looks pretty hard to take apart and put back together.

 

[raffy]

I only have about 40 hours or so on ours, so I haven't done any valve adjustment yet. I would wait until the 200 hours rather than doing it once a year regardless of hours. The latter seems a bit excessive to me!

 

[Ausfahrt]

Which begs the next question. Since the EU2000i does not come with an hour meter, are you guys adding one or guessing?

And if you're adding one, please elaborate. Preferably with pictures.

 

[Schmoe]

Another thing to remember is that if your using those orange extension cords, your going to lose some efficiency. What I and a lot of other neighbors have done during power outages in ice storms and tornadoes, is akin to the "suicide" cord, but with a little better knowledge. Take the 230 volt circular plug and get some good quality 8/3 or 10/4 type of electrical cord. Where the AC compressor is, there is (well, in our neighborhood and probably code requirement) an outside 60 amp circruit breaker. Once you've connected the wires to the plug, take the other end and connect it to the AC circuit breaker (SHUT THE MAIN OFF FIRST) and then you can backfeed to the house. You'll have to know what breaker does what and only turn on the ones you absolutely need like the refrigerator, freezer, some wall sockets, etc. etc. Works well.