But, YOUR signal would be coming late to the party and if I have a system that eliminates commonly monitored signals, locates them using multiple receivers and weeds out the sources that are not in areas where a drone pilot might want to stand/sit/hide. Then if you eliminate all the signals that are simply not strong enough to be useable by a drone flying over the distant lawn I'm trying to protect, there isn't much left to look at but your signal.
I don't agree... There are ways to carefully control WHERE the jamming is effective and barring multi-path and reflections it is not that hard to be pretty limited outside the bounds. You don't go in with RF blazing in all directions and a 100W PA (although that would do it), you put in multiple directional antennas, putting out a few watts each, watch where you put them and where they are pointed.
I think you could be pretty effective and not bleed over into the public's space, but if you did? So what. Your WiFi router runs under part 15, which means you have ZERO protection from interference legally. For instance, part of the WiFi spectrum overlaps a Ham allocation, this means that I can (as a ham) legally run 1,500W PEP on the WiFi band which would likely wipe out WiFi for the whole town. I might get complaints, but legally I'm golden because part 15 devices have no protection from licensed services.
I never said it was a perfect solution, only that it might be a good idea to try to do this. There really isn't that many WiFi connections out there to monitor, especially ones that would have enough coverage to enable the control of a Hobbyist's drone on a public street. Surely one could winnow down the possible bad guys by keeping track of the environment and filtering out the benign signals and those devices that where connecting to the known Access Points, then looking at the signals left and eliminated any that where too weak to be used. I'm guessing you will have a pretty short list after that...
You all act like it's not possible to tell where a specific signal comes from.... All you need is a couple of direction finders tied together and you can develop a pretty good location for *THAT* WiFi signal and decide if it is new, if it's within a specified area and do all this very quickly. So I might not be able to determine exactly what the traffic means, but I can pretty quickly decide if it's a possible threat coming from the clearing over there and not something I've monitored for weeks on end in the office building across the street. How hard is this? If I can image it, I'm sure some smart guys have implemented this already...
Which is why you put up GPS jamming and physical barriers too. Inertial nav is only accurate over short distances, unless you have some external way to calibrate your nav system and can remove the various bias issues caused by vibration, temperature changes and other things that cause changes in the gyros (mechanical, laser ring or otherwise). Usually inertial nav's need to be calibrated, and they do that with GPS (or some other system like LORAN) in order to maintain enough accuracy over time.
Nothing is perfect, but you do the best you can with the resources you have and you live with the risks you cannot afford to fix. I'm suggesting that there is bigger bang for the buck in other things than trying to go out and detect these things in flight.
I'm suggesting we JAM 2.4Ghz around the Whitehouse lawn. Make it impossible for WiFi to work more than a few feet. Then I'm suggesting we track WiFi signals in an effort to catch the pilot, not the aircraft. There are ways to do this w/o being totally disruptive to WiFi service in the surrounding area, or trying to find the needle that pops up in the haystack.
But this is but a small part of the whole plan where physical barriers play a part too....
However, nothing is perfect and nobody has endless resources, so you make a list of risks and how to limit them, pick the things from the list that get you the most risk reduction for the money and live with the rest or go get more money until you CAN live with the risks that are left..
The self piloted drone doesn't get to it's destination w/o a GPS fix. Short range GPS jammers are off the shelf, *easy* use, and not expensive.
Remember, I'm saying that detection is down on my list of things to develop, that other things have a better cost/reward and are based on existing technology.
If they are that well funded, catching their drone is unlikely to be your primary worry.
Look, they could just set up a mortar and shell the white house if they where well enough funded, and there is very little you can do to stop a mortar shell in flight and I'm not even going to guess how hard it would be to get your hands on one if you where well funded... Everything has it's limits.
Personally I don't think concentrating on the detection problem is the best approach. We can jam, and we can put up barriers and reduce a lot of the risks with very low cost. We already have RF direction finding capability which could be deployed to pinpoint not only the drone but the pilot's location, it's a little costly, but it's out there and would be nearly off the shelf. Trying to build a RADAR or IR sensor to hone in on the drone is a nice idea, but high cost, low reward.
Personally I would consider the surveillance activity just as dangerous. Despite what they tell you, all security systems have weak points which may not be visible externally, but if you can observe from the right angles become obvious. Knowing the weak points in advance can make a successful assault out of a bad idea.
I suggest a multilayered approach.. RF jamming, Signal detectors, GPS jamming as well as physical barriers (nets, trees, fences etc). Couple that with a vigorous response to folks flying these things where they shouldn't and the bulk of the problem goes away...
They use a set of well known frequencies, usually 2.4Ghz WiFi or the old model aircraft band. Now you can "adjust" these if you know what you are doing, but off the shelf, this is what you generally get.
It's about being able to deflect them and prevent them from doing bad things.
Sure, it's easier to deal with something you can detect in the first place, but if you can effectively block them by putting up barriers, physical and electronic you will have succeeded in your primary goal. So here's my approach..
1. Do your best to detect them, use sound, video and detect the RF signals emitted by the device and the pilot.
2. Erect physical barriers that are not visible to the operator or the device. I'm thinking there is a LOT you can do with simple fishing line in this regard, but I'm sure a lot of tall trees would serve an excellent purpose too. Put up an obstacle course.
3. Put up electronic fences using short range GPS and WiFi jamming around the "protected" area. You can effectively reduce the ability of a drone to find it's way around and make it impossible for it to be remotely controlled.
4. Concentrate your efforts on finding the PILOT. They will likely have an RF transmitter in their hands, so it shouldn't be that hard, unless the drone is self guided (which is why you jam GPS and provide physical barriers).
5. And Finally, if you do detect something flying where you don't want, come up with some non-lethal ways of bringing it down. You don't need to fire anti-aircraft guns at it, there are ways I can think of which wouldn't present much risk to people, but would be effective in bringing down your average hobbyist's drone.
So I say again, detection is but a small piece of the total security puzzle here, and trying to use audio detection is about the LAST way I'd try it...
What's happening is providers have entered an era where the supply of the product (cloud services) has saturated the market and the low volume, high overhead operations cannot stay in business. It's the natural "survival of the fittest" phase where the overpopulation of folks providing this service are being weeded down to the handful who will survive.
Like the Hula-Hoop, tickle-me-Elmos and Pet Rock, the fad is reaching it's peak and it's down hill from here. Sell any stock you have in this market....
1. HUGE data generally requires processing power to sort though, so where it might be cheaper to by shares of some data center's pile of rack mounted servers, once you get to a certain size, building your own makes financial sense. I'm guessing, but it sure seems to me that if you are big enough to be worried about how long it takes to move your data, you will have it locally processed anyway and won't be dependent on a cloud provider.
2. Data has value that is largely age based. Newer data is worth more than the old stuff. So if you *really* have a lot of data laying around that you depend on, you have a design and implementation problem with your big data operation. And if you don't have a design issue and really ARE processing that much data, then transferring the historical data to another provider is largely unnecessary, just switch your data feeds to the new provider and turn off the old provider once the data it has gets stale, which shouldn't be too long.
Cloud services are pretty much fungible... If provider A tries to turn the thumbscrews, provider B will just under cut them in price and customers will switch in droves the next time the service contract comes up for renewal.
What will actually happen (if it's not already) is that a small number of larger cloud service providers will corner the market and drive the smaller and less efficient providers into mergers, consolidation or just plain out of business. You will end up with 3 or 4 major players, maybe more, but all large, who will dominate the market, control prices to keep the small upstarts from getting much of a foothold in the market.
The price gouging won't really start until you get the number of vendors down to near to 2 and everybody else is afraid of trying to enter the market because there is no growth left. Then prices will go up, but only enough to make the big 2 some cash, while keeping it hard for an upstart to undercut them and grab market share.
Heh I should have read your whole post before replying to the first line, but let me pick you apart in another one instead.
Naw... This EE recognizes when there isn't enough understanding on the other end to make it worth the argument. I've responded in another post, but I'll summarize here for those who don't want to wade though the technical details.... It is you who doesn't understand very much beyond basic circuits. It may have been 25 years since I got my BSEE, but I'm pretty sure the principles we are discussing here haven't changed all that much. However, the state of the art in power supply design HAS changed, and it's changed ALOT in that 25 years. We don't use the traditional power transformer to change voltages for electronic equipment anymore, we use "switchers", which truth be told really have transformers buried inside them, only not ones that transform 60 Cycle current from one voltage to another, but ones that transform AC in the Kilohertz range from one voltage to another. ALL switchers really run on DC and almost without fail the FIRST thing that happens in the design is you rectify the AC coming in to make DC out of it. This is state of the art today.
Now I'm not a power supply designer, but a software engineer, but that doesn't mean I don't keep up with my Electrical Engineering roots. I'm a ham radio operator and use my training on a regular basis in my hobby. I also assist with the design and implementation of Solar powered "off grid" power systems for a non-profit missionary organization so I'm not totally out of touch, even if my professional experience is pretty much just software.
SO, good day to you young one... You really need to brush up on your electronics in practice and spend some time looking at modern electronic equipment designs and do a bit of reading where your assumptions don't really match reality...
You'd think that most of the "heating" devices in your home would work fine on DC with only a few modifications. Especially that water heater and ALL of the incandescent light bulbs in the house...
Did you know that a lot of your electronic devices work great on about 100V DC and wouldn't require any modifications? Most modern switching power supplies really don't care if it's AC or DC on the input, they work just the same either way. Don't just go out and hook up your expensive flat screen to the Prius battery (it can damage stuff sometimes) but chances are it would work... My Laptop charger, a PC desktop and LCD display along with a 30A 12VDC switching supply for my radios all worked just fine...
Personally, I think we should go with HIGH voltage DC, use it where it makes sense, and not freak out about having to convert it to AC when the need arises.
Heh I should have read your whole post before replying to the first line, but let me pick you apart in another one instead.
1. Most stuff just works on high voltage DC as discussed above. Most switching power supplies simply don't know or care about AC or DC and due to their efficiency switching power supplies are used in almost everything electronic.
Absolutely wrong. The first thing most power supplies do is step down from high voltage AC to something in the general range of whats needed on the highest output value. They step down with a transformer. That transformer only works with AC, if you put DC in it, you're just going to burn it up as it turns into a magnet carrying more current (because its not AC, so the there is no inductive resistance, so there is more current). Please don't give anyone advice on electricity. Ever.
You are living in the past on this one. Most modern electronic equipment utilize switching power supplies because they are cheaper to make, lighter and more efficient. Modern switching supplies almost invariably just rectify the AC into DC as the first step, usually using a full wave rectifier. Full wave rectifiers don't care if you feed them with AC or DC, you get DC out either way and as long as you have the right DC voltage range coming out of the rectifier, the switching power supply will work just as well on AC as DC. Where this is not UNIVERSALLY true (you CAN damage some stuff doing this), it is generally true.
Now, I want to point out to you that I did say there where exceptions. Devices that employ transformers and induction motors will NOT work on DC. That includes CFL's, Ceiling Fans, some Wall warts, most major appliances and the like, but it's pretty obvious they won't run on 12 V DC either...
2. It's easier (and more efficient) to use high voltage DC for charging the batteries. All you need is a rectifier to convert that 220 into about 250V DC and charge the batteries, which is about as simple and efficient as it comes.
... You do realize those batteries you're referring to are actually made up of a bunch of smaller batteries right? There is no single cell at 200v. You aren't charging one 200v batter, you're charging a handful of 12v batteries that you're just blissfully ignorant of.
And you seem to be ignoring the fact that that 12V (aka 13.8V) battery *really* is just a number of 2.3 Volt cells (like 6) strung into a series to get you up to 12 V. So we put 100 in series and get a working voltage of about 230V DC? How's that an issue of ignorance? Or, parish the thought, we just take 10 of your standard 12V batteries and connect them in series to get 120 (138) Working voltage?
It's all for naught anyway because different battery chemistry gives you different cell voltages. But no mater what the battery chemistry, you just string enough cells in series to get you up to the desired working voltage... Or that's what electrical engineers had been designing a long time before I got my EE degree..
3. It's easer (and more efficient) to make an inverter that uses high voltage DC as input. It's pretty easy to just flip the current one way then the other to get AC sufficient to run most induction motors and transformer powered devices.
You have absolutely no idea what you're talking about. The conversion from DC to AC is THE BIGGEST LOSS in the inverters you're referring to. The actual transformer itself is pretty damn efficient if designed properly. Dealing with high voltage DC is extremely dangerous. It ARCs over distances that AC won't. You can put 200v AC traces on a circuit board with little space between them. Do the same thing with the same DC voltage and the board is going to randomly arc all over itself.
So are you claiming that YOUR design where you use a transformer to step down to 12 V THEN rectify it (which is the classi
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I was thinking about nets tied to bean bags launched so they spin myself...
But, YOUR signal would be coming late to the party and if I have a system that eliminates commonly monitored signals, locates them using multiple receivers and weeds out the sources that are not in areas where a drone pilot might want to stand/sit/hide. Then if you eliminate all the signals that are simply not strong enough to be useable by a drone flying over the distant lawn I'm trying to protect, there isn't much left to look at but your signal.
I don't agree... There are ways to carefully control WHERE the jamming is effective and barring multi-path and reflections it is not that hard to be pretty limited outside the bounds. You don't go in with RF blazing in all directions and a 100W PA (although that would do it), you put in multiple directional antennas, putting out a few watts each, watch where you put them and where they are pointed.
I think you could be pretty effective and not bleed over into the public's space, but if you did? So what. Your WiFi router runs under part 15, which means you have ZERO protection from interference legally. For instance, part of the WiFi spectrum overlaps a Ham allocation, this means that I can (as a ham) legally run 1,500W PEP on the WiFi band which would likely wipe out WiFi for the whole town. I might get complaints, but legally I'm golden because part 15 devices have no protection from licensed services.
I never said it was a perfect solution, only that it might be a good idea to try to do this. There really isn't that many WiFi connections out there to monitor, especially ones that would have enough coverage to enable the control of a Hobbyist's drone on a public street. Surely one could winnow down the possible bad guys by keeping track of the environment and filtering out the benign signals and those devices that where connecting to the known Access Points, then looking at the signals left and eliminated any that where too weak to be used. I'm guessing you will have a pretty short list after that...
You all act like it's not possible to tell where a specific signal comes from.... All you need is a couple of direction finders tied together and you can develop a pretty good location for *THAT* WiFi signal and decide if it is new, if it's within a specified area and do all this very quickly. So I might not be able to determine exactly what the traffic means, but I can pretty quickly decide if it's a possible threat coming from the clearing over there and not something I've monitored for weeks on end in the office building across the street. How hard is this? If I can image it, I'm sure some smart guys have implemented this already...
Good luck jamming inertia
Which is why you put up GPS jamming and physical barriers too. Inertial nav is only accurate over short distances, unless you have some external way to calibrate your nav system and can remove the various bias issues caused by vibration, temperature changes and other things that cause changes in the gyros (mechanical, laser ring or otherwise). Usually inertial nav's need to be calibrated, and they do that with GPS (or some other system like LORAN) in order to maintain enough accuracy over time.
Nothing is perfect, but you do the best you can with the resources you have and you live with the risks you cannot afford to fix. I'm suggesting that there is bigger bang for the buck in other things than trying to go out and detect these things in flight.
Oh come on..
I'm suggesting we JAM 2.4Ghz around the Whitehouse lawn. Make it impossible for WiFi to work more than a few feet. Then I'm suggesting we track WiFi signals in an effort to catch the pilot, not the aircraft. There are ways to do this w/o being totally disruptive to WiFi service in the surrounding area, or trying to find the needle that pops up in the haystack.
But this is but a small part of the whole plan where physical barriers play a part too....
However, nothing is perfect and nobody has endless resources, so you make a list of risks and how to limit them, pick the things from the list that get you the most risk reduction for the money and live with the rest or go get more money until you CAN live with the risks that are left..
The self piloted drone doesn't get to it's destination w/o a GPS fix. Short range GPS jammers are off the shelf, *easy* use, and not expensive.
Remember, I'm saying that detection is down on my list of things to develop, that other things have a better cost/reward and are based on existing technology.
If they are that well funded, catching their drone is unlikely to be your primary worry.
Look, they could just set up a mortar and shell the white house if they where well enough funded, and there is very little you can do to stop a mortar shell in flight and I'm not even going to guess how hard it would be to get your hands on one if you where well funded... Everything has it's limits.
Personally I don't think concentrating on the detection problem is the best approach. We can jam, and we can put up barriers and reduce a lot of the risks with very low cost. We already have RF direction finding capability which could be deployed to pinpoint not only the drone but the pilot's location, it's a little costly, but it's out there and would be nearly off the shelf. Trying to build a RADAR or IR sensor to hone in on the drone is a nice idea, but high cost, low reward.
Personally I would consider the surveillance activity just as dangerous. Despite what they tell you, all security systems have weak points which may not be visible externally, but if you can observe from the right angles become obvious. Knowing the weak points in advance can make a successful assault out of a bad idea.
Still, being able to pinpoint the pilot based on RF emissions and get there quickly might be a good idea...
I suggest a multilayered approach.. RF jamming, Signal detectors, GPS jamming as well as physical barriers (nets, trees, fences etc). Couple that with a vigorous response to folks flying these things where they shouldn't and the bulk of the problem goes away...
Tune it to the 2.4 Ghz WiFi band too... That will get you the bulk of these things, along with the pilot's equipment..
Better yet, just jam WiFi and folks won't be able to use these things to start with...
They are controlled by radio which can be detected.
That will only find you the pilot, which is not a bad thing, but it's not the direct threat at this point..
They use a set of well known frequencies, usually 2.4Ghz WiFi or the old model aircraft band. Now you can "adjust" these if you know what you are doing, but off the shelf, this is what you generally get.
It's about being able to deflect them and prevent them from doing bad things.
Sure, it's easier to deal with something you can detect in the first place, but if you can effectively block them by putting up barriers, physical and electronic you will have succeeded in your primary goal. So here's my approach..
1. Do your best to detect them, use sound, video and detect the RF signals emitted by the device and the pilot.
2. Erect physical barriers that are not visible to the operator or the device. I'm thinking there is a LOT you can do with simple fishing line in this regard, but I'm sure a lot of tall trees would serve an excellent purpose too. Put up an obstacle course.
3. Put up electronic fences using short range GPS and WiFi jamming around the "protected" area. You can effectively reduce the ability of a drone to find it's way around and make it impossible for it to be remotely controlled.
4. Concentrate your efforts on finding the PILOT. They will likely have an RF transmitter in their hands, so it shouldn't be that hard, unless the drone is self guided (which is why you jam GPS and provide physical barriers).
5. And Finally, if you do detect something flying where you don't want, come up with some non-lethal ways of bringing it down. You don't need to fire anti-aircraft guns at it, there are ways I can think of which wouldn't present much risk to people, but would be effective in bringing down your average hobbyist's drone.
So I say again, detection is but a small piece of the total security puzzle here, and trying to use audio detection is about the LAST way I'd try it...
Let's call it a cloud burst and let it go..
What's happening is providers have entered an era where the supply of the product (cloud services) has saturated the market and the low volume, high overhead operations cannot stay in business. It's the natural "survival of the fittest" phase where the overpopulation of folks providing this service are being weeded down to the handful who will survive.
Like the Hula-Hoop, tickle-me-Elmos and Pet Rock, the fad is reaching it's peak and it's down hill from here. Sell any stock you have in this market....
Not really a problem for two reasons....
1. HUGE data generally requires processing power to sort though, so where it might be cheaper to by shares of some data center's pile of rack mounted servers, once you get to a certain size, building your own makes financial sense. I'm guessing, but it sure seems to me that if you are big enough to be worried about how long it takes to move your data, you will have it locally processed anyway and won't be dependent on a cloud provider.
2. Data has value that is largely age based. Newer data is worth more than the old stuff. So if you *really* have a lot of data laying around that you depend on, you have a design and implementation problem with your big data operation. And if you don't have a design issue and really ARE processing that much data, then transferring the historical data to another provider is largely unnecessary, just switch your data feeds to the new provider and turn off the old provider once the data it has gets stale, which shouldn't be too long.
Sounds like I'm in the wrong business....
Cloud services are pretty much fungible... If provider A tries to turn the thumbscrews, provider B will just under cut them in price and customers will switch in droves the next time the service contract comes up for renewal.
What will actually happen (if it's not already) is that a small number of larger cloud service providers will corner the market and drive the smaller and less efficient providers into mergers, consolidation or just plain out of business. You will end up with 3 or 4 major players, maybe more, but all large, who will dominate the market, control prices to keep the small upstarts from getting much of a foothold in the market.
The price gouging won't really start until you get the number of vendors down to near to 2 and everybody else is afraid of trying to enter the market because there is no growth left. Then prices will go up, but only enough to make the big 2 some cash, while keeping it hard for an upstart to undercut them and grab market share.
When it rains it pours....
Provider one rents their servers from Provider 2. Provider 2 rents their servers from Provider 3. Provider 3 rents their servers from Provider 1.
We have a feedback loop and soon the cloud is a black hole!
I pretty much consider it a black hole already..
Heh I should have read your whole post before replying to the first line, but let me pick you apart in another one instead.
Naw... This EE recognizes when there isn't enough understanding on the other end to make it worth the argument. I've responded in another post, but I'll summarize here for those who don't want to wade though the technical details.... It is you who doesn't understand very much beyond basic circuits. It may have been 25 years since I got my BSEE, but I'm pretty sure the principles we are discussing here haven't changed all that much. However, the state of the art in power supply design HAS changed, and it's changed ALOT in that 25 years. We don't use the traditional power transformer to change voltages for electronic equipment anymore, we use "switchers", which truth be told really have transformers buried inside them, only not ones that transform 60 Cycle current from one voltage to another, but ones that transform AC in the Kilohertz range from one voltage to another. ALL switchers really run on DC and almost without fail the FIRST thing that happens in the design is you rectify the AC coming in to make DC out of it. This is state of the art today.
Now I'm not a power supply designer, but a software engineer, but that doesn't mean I don't keep up with my Electrical Engineering roots. I'm a ham radio operator and use my training on a regular basis in my hobby. I also assist with the design and implementation of Solar powered "off grid" power systems for a non-profit missionary organization so I'm not totally out of touch, even if my professional experience is pretty much just software.
SO, good day to you young one... You really need to brush up on your electronics in practice and spend some time looking at modern electronic equipment designs and do a bit of reading where your assumptions don't really match reality...
You'd think that most of the "heating" devices in your home would work fine on DC with only a few modifications. Especially that water heater and ALL of the incandescent light bulbs in the house...
Did you know that a lot of your electronic devices work great on about 100V DC and wouldn't require any modifications? Most modern switching power supplies really don't care if it's AC or DC on the input, they work just the same either way. Don't just go out and hook up your expensive flat screen to the Prius battery (it can damage stuff sometimes) but chances are it would work... My Laptop charger, a PC desktop and LCD display along with a 30A 12VDC switching supply for my radios all worked just fine...
Personally, I think we should go with HIGH voltage DC, use it where it makes sense, and not freak out about having to convert it to AC when the need arises.
Heh I should have read your whole post before replying to the first line, but let me pick you apart in another one instead.
1. Most stuff just works on high voltage DC as discussed above. Most switching power supplies simply don't know or care about AC or DC and due to their efficiency switching power supplies are used in almost everything electronic.
Absolutely wrong. The first thing most power supplies do is step down from high voltage AC to something in the general range of whats needed on the highest output value. They step down with a transformer. That transformer only works with AC, if you put DC in it, you're just going to burn it up as it turns into a magnet carrying more current (because its not AC, so the there is no inductive resistance, so there is more current). Please don't give anyone advice on electricity. Ever.
You are living in the past on this one. Most modern electronic equipment utilize switching power supplies because they are cheaper to make, lighter and more efficient. Modern switching supplies almost invariably just rectify the AC into DC as the first step, usually using a full wave rectifier. Full wave rectifiers don't care if you feed them with AC or DC, you get DC out either way and as long as you have the right DC voltage range coming out of the rectifier, the switching power supply will work just as well on AC as DC. Where this is not UNIVERSALLY true (you CAN damage some stuff doing this), it is generally true.
Now, I want to point out to you that I did say there where exceptions. Devices that employ transformers and induction motors will NOT work on DC. That includes CFL's, Ceiling Fans, some Wall warts, most major appliances and the like, but it's pretty obvious they won't run on 12 V DC either...
2. It's easier (and more efficient) to use high voltage DC for charging the batteries. All you need is a rectifier to convert that 220 into about 250V DC and charge the batteries, which is about as simple and efficient as it comes.
... You do realize those batteries you're referring to are actually made up of a bunch of smaller batteries right? There is no single cell at 200v. You aren't charging one 200v batter, you're charging a handful of 12v batteries that you're just blissfully ignorant of.
And you seem to be ignoring the fact that that 12V (aka 13.8V) battery *really* is just a number of 2.3 Volt cells (like 6) strung into a series to get you up to 12 V. So we put 100 in series and get a working voltage of about 230V DC? How's that an issue of ignorance? Or, parish the thought, we just take 10 of your standard 12V batteries and connect them in series to get 120 (138) Working voltage?
It's all for naught anyway because different battery chemistry gives you different cell voltages. But no mater what the battery chemistry, you just string enough cells in series to get you up to the desired working voltage... Or that's what electrical engineers had been designing a long time before I got my EE degree..
3. It's easer (and more efficient) to make an inverter that uses high voltage DC as input. It's pretty easy to just flip the current one way then the other to get AC sufficient to run most induction motors and transformer powered devices.
You have absolutely no idea what you're talking about. The conversion from DC to AC is THE BIGGEST LOSS in the inverters you're referring to. The actual transformer itself is pretty damn efficient if designed properly. Dealing with high voltage DC is extremely dangerous. It ARCs over distances that AC won't. You can put 200v AC traces on a circuit board with little space between them. Do the same thing with the same DC voltage and the board is going to randomly arc all over itself.
So are you claiming that YOUR design where you use a transformer to step down to 12 V THEN rectify it (which is the classi