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Im new to forums. I don't really post or post at all. So far I like the mentality here. I mean who doesn't like big inverters that actually work...? This might be totally left field and possibly counter productive to your business' goal and what you want to produce for consumers but I started looking at property and powering it in its entirety a little different then the one big inverter idea. The reason for the change of thinking was because no matter how well a product is put together, shit happens or a user made a mistake on lightning protection or they shorted something on accident and yes that's what overcurrent protective devices are for such as fuses and breakers and what not, but if the main inverter goes down how f'd are you till you can get it fixed? I'm not trying to say anything counter to what you guys have done and are doing I just wanted to throw some different ideas at ya and possibly begin to make them for your business. My thought process these days is to have everything as much as possible converted to DC Devices. Lights. a/c's. fridges.. They make a lot of dc appliances now using inductive motors. obv changing everything to that all at once isn't overnight but I would have all my lights be on DC power and have them and the fridge on their own battery bank and solar array. and utilty charging if I had the utility at my leisure. then would have arrays for each room of the house or id have it in sections. for example, the lights will be all on one bank and array and circuit w its own breaker panel and disconnect and all that. then id prob do like appliances on their own bank w most likely a motor start run capable inverter with a mixture of starter/deepcycle dual batteries if I was able to but If not just deep cycle then. I don't know how to have appliances start up using starter batteries and then once running have them switch to the deep cycle batteries. I'm sure its possible but I don't know as of now. id have entertainment like tvs computers, internet on its own array and bank and then id have the outside on its for security cameras, water pump, electric opening fence or whatever. I might be able with an isolator use just one solar array and have it go to a charge controller and then to an isolator to feed the different kinds of battery banks, but its just an idea at this point. Im not trying to counter your inverters that seem to be looking nice and testing well. I was just saying, maybe push products that are dc or make some of our own. well my gf is bitching at me and I lost my train of thought. just wanted to say nice on the inverters, and to give some thought to pushing other products that are dc powered. just cuz it allows for the batteries to be utilized to their fullest capacity w no loss due to conversion from dc to ac. although its minimal It still accounts for more battery time .
Split to a separate topic.
SO...I actually did pretty much exactly this with my off-grid setup. All LED lights run direct off the 48v battery bank (via an LED driver board I designed). Water pumps run off a step-down from 48v -> 24v. A lot of "car" things can be utilized via 48v -> 12v step-down converters (routers, digital clocks, etc.)...and there's even 48v -> 19v step down converters available for powering laptops and LCD monitors! I went so far as to hack my 'fridge to run mostly on 12v DC--well, everything apart from the compressor and defrost coils. But that sort of hacking is definitely not a DIY project.
I would not recommend running 180vDC to outlets to run appliances...you're going to have serious problems with corrosion (which is part of why AC won out way back), not to mention 180vDC being an extremely dangerous shock hazard--to mention nothing of an arc hazard, and requiring specialized breakers. (DC doesn't "let go" like AC does.)
I don't know how to have appliances start up using starter batteries and then once running have them switch to the deep cycle batteries. I'm sure its possible but I don't know as of now.
If we're referring to synchronous AC motors, this is not technically possible--as synchronous AC motors require an AC sine wave in order to function. Note that "universal" (brushed) motors don't care if they're run on AC or DC.
The biggest reason that DC appliances aren't very common...is because most people are trying to "off-grid" their house. And I have yet to see a house that was pre-wired for both AC and DC power. For most people, it's way simpler to just wire an inverter to their breaker panel and "call it good." But for those of us who want to squeeze every last watt of power out of our solar setup...yes, DC on the small appliances is hands-down the way to go. Keep it at or below 48v for safety, though. 100vDC will happily pull a nice white-hot inch-long arc. Which if not used with properly biased AND rated DC breakers, can unquestionably serve as a foolproof firestarter for that cold morning. (Some DC-rated breakers use a magnet to "quench" the arc; if the DC polarity across the breaker is wrong, the breaker will actually catch on fire when turned off / tripped.)
Here's a video to clearly show the difference:
I was considering converting an old evaporative cooler to 24V DC and running it off the charge controller load output. It would require changing the water pump and fan. The idea was to keep the PowerJack inverter cooler during the 110° summer days. What happened is later in the summer, the inverter stopped shutting off in the heat. After a few long periods of operation, the system somehow became more reliable.
Hum, well reallly almost everything runs off of DC as Sid pointed out. Just some things are built for AC as compressors that uses 2 or 3 phase.
I mean hell even Tesla runs DC until it gets to the motor which is a 3 phase AC motor, so it takes the 400vdc and convertes it to AC to the motor.
But, yeah, if you know what your doing, you can run pretty much all your stuff on DC useing step up or step down converters, and mainly just know what the device requires, and cut off the cord or buy the required plug to the device and solder it to a converter to power the device in question.
AC just travels over wire better then DC, and that is why its used, and then its converted back to DC to power our devices since its well at the end point.
But, yeah its easier to just run the house off of a GS Inverer to the breaker box, and let your devices handle all the step up or down conversion. Really not going to use up that much more power then what it takes to convert everything to DC.
Just some things are built for AC as compressors that uses 2 or 3 phase.
Synchronous AC motors (capacitor start / capacitor run, etc.) are found in a number of household appliances--most notably most refrigerator and freezer compressors. (The newer "variable speed" or "linear" compressors run from a DC bus.) Said motors require single-phase AC power (i.e. standard wall outlet).
Shaded-pole motors (often used in smaller fans) also similarly require an AC power source to operate. (Some solenoids used in older appliances also require AC; I have one fairly powerful one that works fine on AC, but will melt wiring instantly on equivalent DC.)
We have a hair trimmer that requires AC to operate (it's not battery powered).
Some PFC-based power supplies may require AC in order to function, as they internally run a 400v DC bus. (120vAC rectified is ~180vDC.)
Some appliances rely on the 60Hz AC wave to run their internal clocks (microwave ovens have been most problematic here in my experience).
So yes, some things can be run on DC--but there's a lot of caveats.
...easiest ones are devices with wall warts that step the wall AC down to low voltage DC power. Those are pretty easy.
It is worth mentioning that there are reasons why AC is the standard basically world-wide at this point. There are some notable exceptions, like cars, rv, marine - but AC is the reference.
There's a bunch of reasons, but a major one is transmission efficiency - with very low losses you can change the voltage to something optimal for the situation. Saves crazy amounts of money in wiring costs alone. DC buck and boost converters exist, but they are much less efficient and far more complicated than a basic transformer.
The conundrum presented to we off-grid folk is Batteries. Someone invents an AC battery and the game changes overnight. Without the need for an inverter, suddenly the reason to "use DC for as much as possible" evaporates.
It's also notable that inverters get more efficient as the DC voltages get higher. Start with a 240v battery bank - much fewer amps, smaller components, less heat generation, far better efficiency - suddenly the one advantage DC has (not needing an inverter for BESS) melts away.
You could even get rid of the transformer by starting with a 120v bank and operating a pair of inverters in split-sync. Theoretically the components would be the same size - you would just need 2 of each of them. There goes [the majority of?] the shipping weight.
I am heavily "simplicity" driven - i'll sacrifice a LOT to keep something simple. My system is centered around a DC bus (DC Generator, Solar, and Batteries) and even i can't be bothered to convert everything to DC. Basically unless it is practical to get literally every continuously running device on DC, might as well stick with AC all the way as you'll have to run the inverter anyway - might as well put the effort toward making your load demand lower with more efficient equipment.
It is worth mentioning that there are reasons why AC is the standard basically world-wide at this point. There are some notable exceptions, like cars, rv, marine - but AC is the reference. There's a bunch of reasons, but a major one is transmission efficiency - with very low losses you can change the voltage to something optimal for the situation. Saves crazy amounts of money in wiring costs alone. DC buck and boost converters exist, but they are much less efficient and far more complicated than a basic transformer.
Fully agreed there 😉
Adding to the above, another reason that AC is mainstream, is because back when electricity was first being put into widespread service, semiconductors had not yet been invented.
For example, the Hoover Dam was finished in 1936. Its express purpose was a hydroelectric generation--which actually was considered as far back as 1902 (according to Wikipedia).
But wait...the transistor was not viably usable until the 1950s. Without semiconductors, DC power conversion is basically impossible. And efficient DC power conversion such as is available today...well, simply didn't exist.
Which meant that simple, robust AC transformers ruled the power grid--simply because there was no viable alternative. And once the huge "grid" infrastructure had been implemented across thousands of square miles of the world...changing it is almost an insurmountable task. Which is why everything stays AC.