Harman Battery Backup - Surprise

[tjnamtiw]

Another thread was talking about the battery backup system that is available for the Harman stoves and it got me interested if it could be used for Quads.
http://www.hearthnhome.com/downloads/communications/batteryBackupInstructionsHarman.pdf

I went googling for the 512 and found that they are made by SEC. No where in the literature did it say pure sine wave so I wrote to the company and asked them. Here's their reply >

''Dear Mr. W*******

It is not. Our SF 707 is pure sine wave.

Ernest Herz, Sales
SEC America, LLC
78 Ethan Allen Drive,
S. Burlington, VT 05403
Tel: 802-865-8388
Fax: 802-865-8389

SEC America - Contact Form Name: ************ Organization: Mr. Address: ****************State: Georgia Zip: 30*** Email: ********** Phone: 706********

Comments: Is your model SF512 a pure sine wave inverter?''

Which leads to the many times asked question concerning pure sine wave vs 'modified sine wave'. It appears that Harman is indirectly saying that modified sine wave is OK. In the attached literature, they also say that the stove can be plugged into a generator. Not a pure sine wave generator, just 'a generator'.

Does anyone use one of these setups?

 

[tfdchief]

I bought an inverter to run the fan on my old Buck 26000 back in 1982 and had to send it back and get a pure sine wave inverter. The first one, not a pure sine wave would not run the fan. The pure sine wave, 400 watt inverter has run my fan on the old Buck many times during power outages.

 

[Mt Bob]

I think it directly relates to the quality of the electronics.Caddilac had lots of problems in late 80's to mid 90's,when alternator would lose a diode,a/c would be in car systems,screwed up the computers.Did not affect other gm products.Eventualy all the cad ecm's got upgraded.You can run a car a long time with a bad diode without hurting anything.

 

[SwineFlue]

No where in the literature did it say pure sine wave

Did you find a distortion spec (% THD) in the literature for the 512H? It may actually be as 'clean' as some pure sine wave inverters. (There is no technical definition of the term 'pure sine wave'... nobody makes a perfect sine wave.)

 

[tjnamtiw]

Did you find a distortion spec (% THD) in the literature for the 512H? It may actually be as 'clean' as some pure sine wave inverters. (There is no technical definition of the term 'pure sine wave'... nobody makes a perfect sine wave.)

No, they said NOTHING about THD or anything else. Not what I expected.
If it was as good as pure sine wave then they wouldn't offer a pure sine wave version, me thinks.

 

[SwineFlue]

If it was as good as pure sine wave then they wouldn't offer a pure sine wave version, me thinks

It only means their 707 model is better than the 512. It could still be as good as another company's pure sine wave model. Just because a Ferrari is faster than a Corvette doesn't mean the Vette is slow.

 

[tjnamtiw]

It only means their 707 model is better than the 512. It could still be as good as another company's pure sine wave model. Just because a Ferrari is faster than a Corvette doesn't mean the Vette is slow.

Now we are back to the 'How pregnant is she?". ha ha ha. Without them showing specs, it's a moot point. SEC said it wasn't pure sine wave. That's all we know. Without an oscilloscope and a 512, who knows? I'll have to get my old one out of the attic and look at my Xantrec PSW to see how pure is pure.

 

[SwineFlue]

Now we are back to the 'How pregnant is she?". ha ha ha. Without them showing specs, it's a moot point. SEC said it wasn't pure sine wave. That's all we know. Without an oscilloscope and a 512, who knows? I'll have to get my old one out of the attic and look at my Xantrec PSW to see how pure is pure.

Not only that, How pregnant is 'enough'? We don't have specs for what any given stove can tolerate. There is an IEEE recommendation that uses 5% THD for power, so that amount is probably safe.
They definitely label the SF512 as a modified sine wave device, but don't provide any THD spec. The SEC technical specs for their SSV series pure sine wave inverters says they are less than 3% THD. That still leaves room for their modified ones to possibly be 5%.

If you can visibly see distortion on your 'scope, I don't know how you would quantify it.