Cheapo Inverters vs. Expensive Ones

[lkruper]

The Magnum Inverters are also battery chargers, they can charge the battery bank with Grid power or generator, It also can do preventive equalization, they have programable settings such as LVD to any voltage in the range and can program to charge your battery in the night or day at any time, also can limit the current to charge the battery to fit any size battery bank in it's range. They are heavy duty, proven long lasting product that is UL listed. They also come with battery temperature senser too.

On the other hand, the cheap inverters are Not UL listed, when a fire in the house and the insurance investigrator fund an electrical appliance is NOT UL listed, they found the best reason and excuse not to pay out any insurance, that won't be cheap to the house owner at all. The cheap inverter usually come with pre-set low voltage cut off at 10.5 volts for 12 volts system or 21 volts for 24 volt and 42 volts for 48 volts system, by that time when your battery bank reach the voltage to cut off, they are dead! need new battery bank, so it will cost more then. Also if you see those DC connectors in the unit, you know that they can't be possible safely deliver the amount of DC current they claim if you know about electricity.

Hope this answer some of your questions. Just think like a cheap Car without any safty features and compare to a well designed expensive comfortable Car with all the air bag and safty features.

Good point! An Inverter/Charger is three pieces of equipment, not one! It is also a transfer switch. A better cost comparison to the cheap inverter would be the Cotek 3000w 48v for about $1000 -> http://www.wholesalesolar.com/291531...0-148-inverter

[paulcheung]

Did you scroll down to the certifications section? There's a lot of information on the page. Overall, it looks pretty legitimate. Is UL listing the only way that you check a product's worthiness or safety? That said, suppose for the sake of my original question that I eventually find one that has the UL mark in the same price range. The real question is, is there any reason to think that a $700 inverter would not do the same job as a $2200 Magnum inverter?

The Magnum Inverters are also battery chargers, they can charge the battery bank with Grid power or generator, It also can do preventive equalization, they have programable settings such as LVD to any voltage in the range and can program to charge your battery in the night or day at any time, also can limit the current to charge the battery to fit any size battery bank in it's range. They are heavy duty, proven long lasting product that is UL listed. They also come with battery temperature senser too.

On the other hand, the cheap inverters are Not UL listed, when a fire in the house and the insurance investigrator fund an electrical appliance is NOT UL listed, they found the best reason and excuse not to pay out any insurance, that won't be cheap to the house owner at all. The cheap inverter usually come with pre-set low voltage cut off at 10.5 volts for 12 volts system or 21 volts for 24 volt and 42 volts for 48 volts system, by that time when your battery bank reach the voltage to cut off, they are dead! need new battery bank, so it will cost more then. Also if you see those DC connectors in the unit, you know that they can't be possible safely deliver the amount of DC current they claim if you know about electricity.

Hope this answer some of your questions. Just think like a cheap Car without any safty features and compare to a well designed expensive comfortable Car with all the air bag and safty features.

[LETitROLL]

More good feedback, thanks. Unfortunately, for me the choice is between a cheap off-grid solar solution or none at all. The budget for a quality system just isn't there. If the grid goes dark, I think I'd rather have a potentially flaky system than nothing. It seems like my only option is to research the crap out of anything I buy and try to verify its quality and durability as best I can, then roll the dice and hope for the best. Surely I am not the only one in this boat?

I had a small budget for an inverter also and got lucky and got a very nice major brand ($600 retail) slightly used 1000/2000 pure sine (for real, not kinda maybe pure sine) for $100. It is not just a matter of quality and durability, read reviews on amazon and other sights you will see that many cheap inverters will not even start up large appliances the very first try, and a smaller output high quality one will. If you expect to actually run more than 1000-2000 watts worth of loads, regardless of what inverter you buy be advised it takes much more in the battery department and you will ruin batteries quickly by undercharging so even more solar will be required and those 2 items will skyrocket a budget.

[Gyro]

high voltage battery cutout

An issue I had with a previous cheap inverter is that the high voltage battery cutoff activated when I did a battery equalization. I could not EQ my batteries at the manufacturer specified voltage (31V) without tripping out the inverter. So I had to either lower the EQ voltage setting on the charge controller or not have an operating inverter while the EQ was in progress. The inverter you listed specs the over voltage protection at 31V +/- 1V, so there is a good chance it would trip out during an EQ. It also specs the over voltage recovery at 31.8V, which make no sense since the over voltage recovery should be lower than the over voltage ??? Maybe its a typo. The 24V Magnum inverter has a high battery cutout of 33.2V, which can handle EQ's no problem. Its issues like this that make all the difference when you buy a quality inverter.

[lkruper]

More good feedback, thanks. Unfortunately, for me the choice is between a cheap off-grid solar solution or none at all. The budget for a quality system just isn't there. If the grid goes dark, I think I'd rather have a potentially flaky system than nothing. It seems like my only option is to research the crap out of anything I buy and try to verify its quality and durability as best I can, then roll the dice and hope for the best. Surely I am not the only one in this boat?

Have you calculated what loads you want to run if the grid loses power? I would imagine it is nowhere near 5000w. You can get a pretty good inverter for the money you are willing to spend on one or two of those "cheap" inverters. The way to size the system is to start with:

0) Conserve as much as possible. Get LED lights. Low wattage appliances.

1) Measure your loads and estimate how much you need to run in case of a failure. Calculate the number of hours you would want to run the necessary loads and then get the average kWh / day as well as the peak watts at one time.

2) Multiply the daily kWh by your days autonomy (eg 5) and then by 1.5 or 2 for inefficiency.

3) Size your batteries with #2.

4) Size your inverter with #1

5) Size solar panels from #1 and #3

Do you need a 5000w inverter? If you scale the rest of your system from that, you will need a large battery bank, larger AWG wires to prevent fire, and lots of solar panels and CC to charge all that equipment.

For example, since your inverter can draw 5000w, so you don't go over C/8 you need at least a 48v 833AH battery bank with 8 batteries. 6v Surrettes at 820AH for 8 will cost over 11K. (Check my calcs!)

Do you need a system that big? It will cost.

[jflorey2]

More good feedback, thanks. Unfortunately, for me the choice is between a cheap off-grid solar solution or none at all. The budget for a quality system just isn't there. If the grid goes dark, I think I'd rather have a potentially flaky system than nothing.

If you need short term backup for power outages, there are plenty of VERY cheap UPSes out there that will provide basic power for small loads for a while. You can usually add batteries to these if you want to extend run times. They run around $200 for a 1200 watt UPS.

If you need long term backup then a generator is going to be cheaper than almost anything else out there. You can get a 3000 watt generator for about $300.

[eric@psmnv]

The basic simple answer is that inverters for large loads need to be very heavy duty, and the parts and manufacturing methods to achieve that are not cheap. So in most/all cases cheap inverters are a mix of not putting out as much as they say, and almost always put out dirtier power than quality more expensive versions, which shortens the life of the loads you plug into them, some people that run reasonable loads of products that are not sensitive to low quality power do fine with cheapo inverters, but all in all those are the type of inverters that earned the nickname "smoke in a can". The best bet is to define a inverter budget then get the best (new or used) quality inverter for that price, it will run as many or more loads than a higher rated cheapo inverter. The cheapo inverters are real and they do work (sometimes) but the ratings are a mirage, so you dont end up getting the great deal you thought you got, especially after you factor in the price you ended up paying for the new TV and Refrigerator 3 months later.

More good feedback, thanks. Unfortunately, for me the choice is between a cheap off-grid solar solution or none at all. The budget for a quality system just isn't there. If the grid goes dark, I think I'd rather have a potentially flaky system than nothing. It seems like my only option is to research the crap out of anything I buy and try to verify its quality and durability as best I can, then roll the dice and hope for the best. Surely I am not the only one in this boat?

[Bucho]

What am I missing here?

That the Chinese are lying to you.

[LETitROLL]

I hear you, and I am certainly in that phase right now, but I do not give up easily. Here's a page that lists about a zillion similar products.

http://www.alibaba.com/showroom/5000w-power-inverter-48v-pure-sine-wave_3.html

I have a hard time believing that all these products are out there causing fires in homes all over the place.

The basic simple answer is that inverters for large loads need to be very heavy duty, and the parts and manufacturing methods to achieve that are not cheap. So in most/all cases cheap inverters are a mix of not putting out as much as they say, and almost always put out dirtier power than quality more expensive versions, which shortens the life of the loads you plug into them, some people that run reasonable loads of products that are not sensitive to low quality power do fine with cheapo inverters, but all in all those are the type of inverters that earned the nickname "smoke in a can". The best bet is to define a inverter budget then get the best (new or used) quality inverter for that price, it will run as many or more loads than a higher rated cheapo inverter. The cheapo inverters are real and they do work (sometimes) but the ratings are a mirage, so you dont end up getting the great deal you thought you got, especially after you factor in the price you ended up paying for the new TV and Refrigerator 3 months later.

[eric@psmnv]

They are not "causing fires in homes all over the place."

I've used several Chinese no-name inverters over the years. They tend to fail moderately gracefully. The most common way is to just start blowing DC fuses; I had three inverters do that after a few weeks to years of use. (Needless to say you should never ever connect one directly to the battery; then you might start fires, but it would be your fault rather than the inverters.)

One started arcing internally. It actually still worked, but started to smell very bad, and I stopped using it. Meant to fix it but never got around to it. It _might_ have started a fire if I left it running for long enough, but I stopped using it before anything like that could have happened.

Another one had an LVD that started disconnecting at higher and higher voltages, making it useless.

Overall, though, about 50% of them worked reliably for as long as I used them, although I did not test them to their limits.

I compare them to the "top tier" inverters I've used over the years - a pair of SW5548's, an SW4024, an SW2512, a Prosine 1800, and an Outback GVFX3648. I had one failure (one of the 5548's) and that was due to serious mistreatment of the inverter (running it at over rated load with air inlet blocked.) No problems with any of the others.

It's your money. If you can afford it, and really want a Chinese inverter rather than a more reliable one, then get it. Take the usual precautions against fire and short circuit. It will most likely work for a while. And even if it doesn't, you will learn something from the experience. The odds of a fire are low but present, and only you can decide if you want to take that risk.

Okay, now that's some excellent information. Exactly the sort of feedback I'm looking for. To be honest, it sounds like a risk I would be willing to take. If I am really concerned that the unit might break after a while, I could buy one or two spares just to keep on-hand and still save a load of money!

[jflorey2]

I have a hard time believing that all these products are out there causing fires in homes all over the place.

They are not "causing fires in homes all over the place."

I've used several Chinese no-name inverters over the years. They tend to fail moderately gracefully. The most common way is to just start blowing DC fuses; I had three inverters do that after a few weeks to years of use. (Needless to say you should never ever connect one directly to the battery; then you might start fires, but it would be your fault rather than the inverters.)

One started arcing internally. It actually still worked, but started to smell very bad, and I stopped using it. Meant to fix it but never got around to it. It _might_ have started a fire if I left it running for long enough, but I stopped using it before anything like that could have happened.

Another one had an LVD that started disconnecting at higher and higher voltages, making it useless.

Overall, though, about 50% of them worked reliably for as long as I used them, although I did not test them to their limits.

I compare them to the "top tier" inverters I've used over the years - a pair of SW5548's, an SW4024, an SW2512, a Prosine 1800, and an Outback GVFX3648. I had one failure (one of the 5548's) and that was due to serious mistreatment of the inverter (running it at over rated load with air inlet blocked.) No problems with any of the others.

It's your money. If you can afford it, and really want a Chinese inverter rather than a more reliable one, then get it. Take the usual precautions against fire and short circuit. It will most likely work for a while. And even if it doesn't, you will learn something from the experience. The odds of a fire are low but present, and only you can decide if you want to take that risk.

[lkruper]

Sorry, maybe you missed the part of my previous comment where I said if I find one that meets the same specs, UL listing, etc. I am no longer comparing the Magnum product to the Safe and Reliable product. I am saying if I find one with the same specs in a lower price range, is there something I'm missing? Never mind, I think we're kind of talking past each other. I appreciate you trying to answer my question.

I was responding to this statement of your: Are you saying that the Magnum inverter sold by wholesalesolar.com which has the same specs is also unsafe? Should I contact them and ask how they can sell such an unsafe product?

I did miss the if.

[eric@psmnv]

It sounds to me like you do advertising for Alibaba Do you?

That's funny. I was about to ask what big-name expensive solar product or installation company you work for.

I'm just a computer networking guy in Nevada. My company hosts medical records for doctors. Ask me a question about data center network infrastructure or data communications protocols and I'm your guy. However, I am obviously clueless about solar electricity, and really electricity in general.

[eric@psmnv]

They don't have the same specs:

Safe and reliable: The MS2000, MS2012, MS2812, and MS4024 are ETL
Listed to the stringent requirements of UL/cUL 458 for mobile use and the
MS2012, MS2812, and MS4024 are ETL Listed UL 1741 and CSA C22.2 #107.1-
01 for renewable energy installations. All models also meet KKK-A-1822E
standards for emergency vehicle use.

Sorry, maybe you missed the part of my previous comment where I said if I find one that meets the same specs, UL listing, etc. I am no longer comparing the Magnum product to the Safe and Reliable product. I am saying if I find one with the same specs in a lower price range, is there something I'm missing? Never mind, I think we're kind of talking past each other. I appreciate you trying to answer my question.

[lkruper]

Now, don't be mean. I thought you said earlier that the UL listing met your requirements for burden of proof. It now appears that you are adding "verifiable reviews" to the requirement, which is reasonable. What other elements do you consider necessary to meet the burden of proof to your personal satisfaction? Aside from a UL listing and verifiable reviews, what else does a web site need to display to meet your standard of proof?

If it does not have credible listing from Nationally Recognized Testing Laboratory I would never read the reviews. I reject immediately. If it does, then I read the reviews and especially ask advice from seasoned veterans who don't have anything to gain from my choice.

It sounds to me like you do advertising for Alibaba Do you?