Latest chinese mystery box: 50KW 90-250V Household Energy Power Saver - Page 1
Forum section: electronics / general

author: jeremy
author_rank: Super Contributor
timestamp: January 28, 2015, 09:10:57 pm
content: Take a look here:http://www.banggood.com/50KW-90-250V-Household-Energy-Power-Saver-Electricity-Saving-Box-p-966573.htmlAnyone have any idea what is inside these things? (if anything at all)

author: Unknown
author_rank: Unknown
timestamp: January 28, 2015, 09:15:09 pm
content: "Bang good" ?? Hahah!Does that mean they go "bang" better than the rest of the one-hung-low brands or something entirely different?I like how it's categorised as "Industrial & Scientific" with a sub-category of "Home Appliance Part".

author: David_AVD
author_rank: Super Contributor
timestamp: January 28, 2015, 09:25:04 pm
content: My guess is a capacitor across the mains and a small LED drive circuit.

author: bktemp
author_rank: Super Contributor
timestamp: January 28, 2015, 09:34:31 pm
content: Quote from: jeremy on January 28, 2015, 09:10:57 pmAt least a blue led, otherwise it would be too easy to say it is not working.The CE logo looks wrong: The distance between C and E is too small:http://en.wikipedia.org/wiki/CE_marking#China_Export

author: AG6QR
author_rank: Frequent Contributor
timestamp: January 28, 2015, 09:43:07 pm
content: Quote from: jeremy on January 28, 2015, 09:10:57 pmNothing useful.I've seen similar miracle power saving devices marketed, claiming to help with power factor correction for inductive loads. Ideally, that might bring the VA down to as low as the actual power being consumed. But there are a few problems with this: Most homes are charged for real power, not VA, so power factor doesn't matter much to the energy bill. The only economically useful thing power factor correction can do in such a home is reduce the excess I^2R losses in the wiring between the meter and the appliance. And there's no way that's going to add up to a measurable percentage savings on the whole house energy bill.Furthermore, this box appears to have one inlet, and no outlet. So it has no way of sensing the current going through the lines, thus no way to use feedback to determine the proper amount of power factor correction needed. Maybe there's a capacitor in the box, but that might be doing as much harm as good.I'll note that this device doesn't explicitly claim to be a power factor correction device, so it may not be one. But if it's not doing power factor correction, then I guarantee that it's not doing anything at all useful. And if it IS doing power factor correction, it's not doing it well enough to pay back the investment within a millennium.Note that it appears the case seems to be designed as a heat sink. If it's dissipating heat, it's consuming power, and thus costing energy.

author: G7PSK
author_rank: Super Contributor
timestamp: January 28, 2015, 09:51:56 pm
content: Nice case though might get one to rip apart, had some bits from that co. before for that purpose.

author: AG6QR
author_rank: Frequent Contributor
timestamp: January 28, 2015, 10:11:42 pm
content: A bit of googling of the model number revealed a teardown.http://www.siongboon.com/projects/2012-01-24_power_saver/Yeah, it's basically a capacitor. And it won't save energy, though in some carefully contrived demonstrations, it may reduce current by changing power factor.

author: codeboy2k
author_rank: Super Contributor
timestamp: January 29, 2015, 01:57:05 am
content: Quote from: G7PSK on January 28, 2015, 09:51:56 pmI was thinking the same then I went looking... For the about same price (US $46.94 shipped, to Canada) I can get 4 cases almost the same sizehttp://www.aliexpress.com/store/product/4pieces-a-lot-aluminum-extruded-enclosure-36x147x155mm/505449_611362850.html

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 29, 2015, 07:56:52 am
content: They can be very useful for shunting EMI and spikes. But you might as well just get some much cheaper motor run caps that do the same thing.

author: Zucca
author_rank: Unknown
timestamp: January 29, 2015, 10:54:15 am
content: Same here, my Bull Shit detector is fully on!I was planning to design a Power Factor correction box for my home by using lots of Capacitors in a rack with relais.But:1) If nobody does that there is a reason.2) Probably it will pay off in 40 years or worste.Take care,

author: VK3DRB
author_rank: Super Contributor
timestamp: January 29, 2015, 12:21:38 pm
content: 50kW...reminds me of the el-cheapo boom boxes of the 80's sporting labels with:2,000milliWatts of Ghetto Blasting Power!In any case there is a chance the unit contains a piece of melamine as a substitute for a circuit board.

author: G7PSK
author_rank: Super Contributor
timestamp: January 29, 2015, 02:44:16 pm
content: Problem with whole house PF correction is at low loads the unit will raise the voltage in the circuit, something I found out the hard way when I was asked to fit a power factor correction capacitor to a arc welding plant, on load ie. while welding all was well but as soon as the arc was broken the voltage on the mains went through the roof, well over 375 volts on a 240 volt line the result bulbs burnt out and electronics blew up the capacitor had to be removed from the arc welding plant this meant arc striking was hard again ended up with only using one third of the capacitor bank which had been supplied by the welder manufacturer as 3 capacitors.

author: albert22
author_rank: Regular Contributor
timestamp: January 29, 2015, 04:37:23 pm
content: I see that they rated it only for 50KW. Why not 1.21GigaWatts.Sure 50KW makes it more credible. Devious marketing strategy.

author: dannyf
author_rank: Super Contributor
timestamp: January 29, 2015, 11:46:25 pm
content: QuoteIt is built on the assumption that most household load is inductance - likely true, giving the motors we have in a house.If so, a simple capacitor does help improve the power factor. If you have a typical utility meter, the benefits (of having this device) accure to the utility company; If you are fortunate to be billed on VA-H, you will benefit from having this device.

author: tom66
author_rank: Super Contributor
timestamp: January 30, 2015, 12:14:19 am
content: Most of a house nowadays is not inductive or capacitive, it's got an SMPS load with spikes near the mains peaks. Fridges, freezers, washing machines etc all work on intermittent cycles, so as much as this device might help correct the power factor in those instances, it's going to work against it in the other instances when inductive loads aren't running. The PF corrector needs to be designed for the load, and operate only when the load operates, else it may as well be useless.Typically, these units contain 5~20uF of capacitance, which according to this calculator, would help correct at best a PF of 0.9995 to 1.000, assuming 5kW load, 41.7A input / 120V AC / 60Hz.http://www.rapidtables.com/calc/electric/power-factor-calculator.htm(that being said I'm not aware of the exact calculation so I could be wrong)