Running solid state electronics from a generator

[jasonryan]

Hey guys,

So this year was my first burn and I'm happy to say it went amazingly well, largely thanks to all the advanced preparation me and my camp mates were able to do thanks to sites like this one. The only thing that really went wrong was our amplifier dying when we ran it on the generator, which wasn't the end of the world, but I'd rather it not happen again next year, so I need some advice.

First of all, our generator is not a Honda eu2000i--not an inverter generator, that is, it's a plain old jobsite Coleman Powermate (yes, I built a baffle box and it works amazingly well). And I should also say that we knew not to run solid state electronics off of it, which is why we bought a battery and a power inverter for it (actually we bought the battery so that we wouldn't have to run the gennie at night and bother our neighbors). Me and the ring leader of our camp had both read the generator's manual whilst we were trying to get it run after it had been sitting for 10 years (learned a lot about small air cooled engines in the process), but I suppose neither of us took the warnings seriously. We knew our amp would use about 100 watts (I have a Kill-A-Watt meter), so the battery should have given us 10 hours of music, but we ran it out after about three hours. Turns out we forgot to check how much current our Christmas lights for our shade structure used--about 300 watts! Doh, they weren't LEDs, they were incandescent. So we ran out the battery and then "somebody" (not me) decided to plug everything in to the gennie... I should be fair and say I didn't stop him when I should have, lol. Things ran fine until the next day when our amp went up in a puff of smoke! I plugged the kill-a-watt into the gennie and noticed it was producing 140 volts, yikes. So that must be what killed it, I'm figuring?

That leads me into my question--the gennie manual says you need a power line conditioner to run solid state electronics. I've done a bit of research and discovered that there really is no standard definition of what exactly a line conditioner is. It could be a simple power strip with a surge protector all the way up to a device which regulates voltage as well as smooths out the sine wave of the current. So my question is, what exactly do I need my power conditioner to do? I *think* I need it to regulate the voltage and make sure it's always delivering 120 volts to my electronics. Am I right?

And does anybody know of an inexpensive solution? I am told we have access to an old UPS whose battery doesn't work anymore. If memory serves, a UPS should have a voltage regulator in it. I still have to confirm this. It may just be a plain old battery backup unit. It's heavy though--can we remove the battery from it and still get the line conditioning? Or is there a better voltage regulator out there for like $30 or something?

Thanks in advance.

-Jason

[Captain Goddammit]

I think you had a good idea to use a battery and inverter for the amp, although you'd do even better to get a decent, pure sine wave inverter.
The cheap generator will fluctuate in voltage and frequency. It's only 60 hz when the motor is spinning at exactly 3600 rpm.
Best solution of course is a better generator. It seems the Kipor Chinese knockoff of the Honda is actually somewhat OK.
Maybe worth a look if a Yamaha or Honda is out of the question.

[BBadger]

It's not really the 140V that is going to kill your electronics, but the spikes of voltage and current that come from those generators. You won't see those on your Kill-A-Watt because the Kill-A-Watt only measures the average power/voltage output, not the transient. The fact that it's showing 140V may indicate a much worse looking waveform that could have large voltage spikes and sharp transitions -- something solid state electronics don't like. Think of what static electricity does to your electronics: a sharp high voltage transition that wrecks delicate circuitry. Incandescents don't care, nor even maybe those DC power supplies for laptops and stuff, but your amp probably assumes you're getting some good power because even if it doesn't kill the amp, it'll sound terrible.

Usually anytime you have something involving motors and electricity, you're going to have a lot of noise, inductive spikes, etc. unless the system is built to respond to such things as Honda generators are. To counteract these problems you need to have filtering so that the output of your power source looks more like the 60hz sine wave that mains power provide to our houses. Even those mains can be noisy, but not as bad what usually comes out of a gasoline-powered generator.

My suggestion? Buy a standalone unit and be done with it. Even if it costs you $200 or so, you may also save your life by not having to deal with circuits involving voltage and current levels that can kill you. It's one thing to solder up some sort of DC power device; another to work with the output from your generator. Do you really want to deal with transformers, capacitors, and all that kind of dangerous stuff? Do you really want to deal with ensuring you have the wiring set up right?

Better yet, as suggested above: buy a better generator. If you're sinking $200-300 into a power conditioner, you might as well put that towards a decent genny. You'll even be able to hear your music better.

[jasonryan]

I can tell you guys right now, I'm not dropping $1000 for an eu2000i just to play music.

BBadger, if I understand you right, you think it's voltage *spikes* that caused the amp to go up in a puff of smoke? If so, why wouldn't I try something like this for $47.25 on amazon?:



I mean... I am not spending $200-300 on a power conditioner, that's for sure. I am looking for the $50 or less solution here.

Btw, I am not sure you're right about the Kill-A-Watt meter. The measurements all look to be real time except for the KW/H, which gives you a total of the kilowatt hours used since you've plugged it in. I say this because I was using it to watch how many watts the stereo was using while it was playing music--and it looked like it was updating about once a second or two (ranging between 80-100 watts).

I haven't tested the generator to see if it's putting out 60Hz exactly and whether it's fluctuating or not--I shall do so.

[GreyCoyote]

The Kill-A-Watt will not, by design, catch transient voltages. It uses a simple capacitor-based sample and hold technique whose RC constant is far greater than any spike. The time constant is about 2.5 times the value of a half-cycle on the powerline. It will catch most (but not all) of the surges (greater than a half-cycle in length) but ignores the spikes. (Spikes are by definition a fraction of a cycle).

If you cant spring for a good genny, your best bet may be a 1980s era transformer-based amp. These are fairly immune to transients and spikes within reason. Should be cheap to find at a garage sale. (you can tell by weight. Lift the amp. If one corner is quite heavy, you have one with a transformer-tyype power supply).

Unfortunately, there is no $50 solution to bad inlet power. Even a UPS in-line will quickly turn to toast as it constantly cycles between battery and line.

One thing you might look for is an old Sola or Best Power ferroresonant isolation transformer. If you can find one, and they are no longer common, and the owner doesnt know what he has, this would be another proven spike killer if you dont mind the inefficiency and noise.

[Token]

You already have the battery and inverter, add another battery and a solar panel to run the sound.

Run the lights from the genny.

[Token]

BTW, line conditioners are old-tech made from big heavy transformers, limiters, band-pass filters to "clip" n filter harmonics.

The heavier the better.

Not related to power-strips that don't filter jack other than lightning strikes.

The APC you listed "may" work, in theory. Depends on how bad the genny is.

[BBadger]

I can tell you guys right now, I'm not dropping $1000 for an eu2000i just to play music.

Well, not just for music. What about for other stuff as well?

BBadger, if I understand you right, you think it's voltage *spikes* that caused the amp to go up in a puff of smoke? If so, why wouldn't I try something like this for $47.25 on amazon?:



I mean... I am not spending $200-300 on a power conditioner, that's for sure. I am looking for the $50 or less solution here.

That voltage regulator might work. The reviews seem to like it. Still, I don't know how it performs for certain loads. Your amp might have different draw characteristics that may not be sufficient for a device like that. Some people report that it doesn't seem to handle mid-sized tube amps that well.

On paying money for power conditioning, the real question you should be asking is: how much is your equipment worth? If you're just driving some cheap-ass amp and speakers, then it's probably not worth spending much on the power. If your gear is more valuable, how much is it worth spending on protection equipment over potentially damaging your gear? You've already friend an amp. Is gambling on the death of another worth saving money on the power conditioner?

The same way with buying a good generator: are you really saving anything if you've bought a generator that is so loud and crappy that you don't want to even use it? What about stuff you have to replace because you either hate it, or it breaks? It's not all about the sticker price you know.

Btw, I am not sure you're right about the Kill-A-Watt meter. The measurements all look to be real time except for the KW/H, which gives you a total of the kilowatt hours used since you've plugged it in. I say this because I was using it to watch how many watts the stereo was using while it was playing music--and it looked like it was updating about once a second or two (ranging between 80-100 watts).

I haven't tested the generator to see if it's putting out 60Hz exactly and whether it's fluctuating or not--I shall do so.

The very fact that your voltage meter isn't jumping around faster than the LCD can even update itself means it isn't measuring transients of any note. Even if the spikes were at 30hz -- half the normal AC frequency -- you probably wouldn't seen the difference in that meter. Most of the transients are going to have far faster responses than that; after all, it's not a slow "spike" that will kill your equipment. Squarish or triangular waves from improperly filtered power supplies can also be problematic; the sharp edges of the square shape can wreck speakers, especially when amplified. Still, they'll register as "60hz" because of the dominant waveform even though they have lots of high-frequency noise.

If you want to see what the actual waveform looks like you should hook up an oscilloscope. Then you can see the temporal changes in the waveform at millisecond or microsecond speeds, not some time-averaged frequency.

[jasonryan]

Regarding amps, I inherited the one I was using and it had been sitting for 2 years. You can safely assume that I didn't bring anything to the burn that I *really* cared about. And I have yet another I've had since 1990 that I haven't used in years because its outmoded. I don't care about them at all, and I know if I fry another I can pick one up for peanuts on craigslist or better yet at an rlspear.com auction over the next year. So, not worried there.

I don't own the gennie I'm using, It belongs to a friend, meaning so far my cost is $0, and I like $0 better than $1000...can ya blame me? Of course, it was loud as hell, but Thinking creatively lead me to build a baffle for it out of some plywood I had (essentially its a 4-sided open top box lined with fiberglass insulation), and I think I only spent about $10 on that. You wouldn't believe how well it works! Night and day. Yes, I know a Honda eu2000i is a nice off the shelf solution for everything, but it's totally overkill. There are other solutions.

I appreciate all the suggestions about buying a new generator, or using my battery & inverter setup, and all of that, but those are solutions I already know about. I'm trying to find out what I don't know, which is what, exactly, is it about the power produced by a non-inverter gennie that causes solid state electronics to die. Is it the voltage spikes? Is it an imperfect sine wave form? Is it more or less than 60hz being produced? Knowing this will help me determine how far I have to go down the power conditioner road, ya know?

So far it doesn't sound like anyone else has actually run into this problem or tried one of these APC voltage regulators, so it looks like its gonna fall to me? I shall report back the results.

Btw thanks to those who have pointed out that the kill-a-watt doesn't show all voltage spikes down to the millisecond! Makes sense.

[BBadger]

Regarding amps, I inherited the one I was using and it had been sitting for 2 years. You can safely assume that I didn't bring anything to the burn that I *really* cared about. And I have yet another I've had since 1990 that I haven't used in years because its outmoded. I don't care about them at all, and I know if I fry another I can pick one up for peanuts on craigslist or better yet at an rlspear.com auction over the next year. So, not worried there.

I don't own the gennie I'm using, It belongs to a friend, meaning so far my cost is $0, and I like $0 better than $1000...can ya blame me? Of course, it was loud as hell, but Thinking creatively lead me to build a baffle for it out of some plywood I had (essentially its a 4-sided open top box lined with fiberglass insulation), and I think I only spent about $10 on that. You wouldn't believe how well it works! Night and day. Yes, I know a Honda eu2000i is a nice off the shelf solution for everything, but it's totally overkill. There are other solutions.

Fair enough.

I appreciate all the suggestions about buying a new generator, or using my battery & inverter setup, and all of that, but those are solutions I already know about. I'm trying to find out what I don't know, which is what, exactly, is it about the power produced by a non-inverter gennie that causes solid state electronics to die. Is it the voltage spikes? Is it an imperfect sine wave form? Is it more or less than 60hz being produced? Knowing this will help me determine how far I have to go down the power conditioner road, ya know?

Honda actually has a pretty good description (visual as well) of what the output power for a generator often looks like. Without knowing the details of the system itself, if the power looks like the top graph, you're going to see some major sharp transitions in voltage. The sharper the transition, the more potential for damage. It's like how a speaker can be killed by pops and clicks in the waveform as the driver tries to overdrive itself to move that quickly.

For electronics, power supply noise can cause short, but powerful bursts of current can wreck the solid state electronics. On computer chips they employ some large diodes to for ESD protection, but your system may not be protected, and the power levels may not be the same. These may not even kill the system immediately, but the stress of being hit by these transitions on each waveform can wear on the electronics. Essentially what you're buying with an aftermarket inverter/regulator is the inverter/regulator that Honda builds into their generator. So it's worth a shot using that inverter for protecting your amps. Hopefully the amp itself has enough capacitance to sustain any power droops (as it should).

Another thing the regulator might do is protect against voltage shocks to the system due to static electricity, or even just starting up the generator. You never know what the on/off current characteristics might be. If there's something like an inductor using power on the same circuit, and it's has some back-emf, your other devices might suffer too.

So far it doesn't sound like anyone else has actually run into this problem or tried one of these APC voltage regulators, so it looks like its gonna fall to me? I shall report back the results.

Well the reviews on Amazon seem positive. Most of the complaints I've seen haven't had to do with the protection, but just that it can't provide enough power at times. I don't think it can hurt attaching one of those to your system; it just might not be appropriate for higher-powered audio systems. Then again, the generator might not be able to supply enough reactive juice anyway.

[jasonryan]

Most excellent sir, thank you. It looks like there are a few different models of those voltage regulators. One thing we are considering bringing next year is a small microwave to reheat our meals (we used the one in the RV this year). Just gotta make sure I get one powerful enough to handle it. That will be, by far, the biggest current draw, so if it handles that, it should handle all the rest (not at the same time of course).

[BBadger]

Keep in mind that while your microwave or toasters will use a lot energy, and quite a bit of power for heat up things quickly too, systems such as sound systems can still require huge amounts of power but in short bursts. That's what those giant capacitors in amps are for: to provide a reservoir of charge for delivering large amounts of power when necessary. If your amp doesn't have enough stored energy, and your power supply can't supply it either, your audio will suffer as it won't have enough power for your drivers. So make sure the amps you use store enough juice to keep the beats flowing.

[gyre]

Why not use a dc car system?
Run a charger into a battery, THEN to the equipment.