[HN Gopher] 1000W 12V -> 220V Inverter
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1000W 12V -> 220V Inverter
Author : hansc
Score : 42 points
Date : 2023-05-31 20:40 UTC (2 hours ago)
(HTM) web link (www.instructables.com)
(TXT) w3m dump (www.instructables.com)
| codetrotter wrote:
| That's pretty neat!
|
| Also, I was not aware that Instructables.com was owned by
| Autodesk. Guess they must've been acquired somewhat recently.
| mikeyouse wrote:
| Not exactly -- almost 12 years ago!
|
| https://investors.autodesk.com/news-releases/news-release-
| de....
| opencl wrote:
| The acquisition was a pretty long time ago but the prominent
| Autodesk branding at the top of the page is relatively recent.
| actionfromafar wrote:
| I think the receptacle looks so scared, because it's about to
| deliver 220V when it's only rated for 110V?
| deng wrote:
| That's a neat little project, but as almost always nowadays,
| don't even expect to save any money by building an inverter
| yourself, unless you have the expensive parts (transformer,
| mosfets, driver board) lying around anyway. Otherwise, the 30$
| mentioned in the article wouldn't even come close to cover all
| the parts in the list.
| rlpb wrote:
| While people are talking about use cases, I've been shopping for
| exactly this. My Nissan Leaf's DC-DC converter that drops the HV
| traction battery down to 12V (well, 14.6V-ish) to supply the
| regular vehicle electrics is apparently 1kW capable, as the heat
| pump needs a lot of power. If you turn the climate control off
| but leave the car on, then you can apparently pull 80A or so from
| the 12V "battery" perfectly fine as the DC-DC converter will keep
| it supplied. This is a relatively safer way of tapping into the
| traction battery without having to deal with the HVDC.
|
| With an inverter, I could then supply (some subset of) my house
| from the traction battery, giving me a theoretical 18 hours at
| 1kW in my case (less efficiency losses).
| jasonpeacock wrote:
| This is one of those "if you don't understand _all_ the words in
| the article then you should not be attempting it " articles.
|
| But it's still fun to read :)
| Am4TIfIsER0ppos wrote:
| Do you think the laborers in china understand all the words in
| this instruction set when they assemble electronics?
| lokar wrote:
| No, but they are doing it on a line and with tools, parts,
| training etc provided by an engineer who does.
| emeraldd wrote:
| ElectroBoom has entered the chat ...
|
| Seriously though, there's enough energy in those numbers to
| seriously mess you or your electronics up. It's not quite like
| a bottle of old nitroglycerin, but it's definitely enough
| energy/power that you must respect it.
| ilyt wrote:
| It's definitely "just buy one", if you _just_ want an inverter.
|
| It is nonetheless interesting if you want to build it as
| component of something more complex, say DIYing a battery bank
| out of some recycled cells
|
| I wonder how many changes would be required to run the whole
| thing on say 24 or 48V. At glance just powering the board with
| 12V source and just feeding more to MOSFETS seems to be enough
| winrid wrote:
| I have a 2kw(?) 12v inverter that I use to power a small welder
| from my vehicle, it's really useful on the go for repairs.
| olyjohn wrote:
| I have an old wall clock from Japan that runs on 110v/50Hz. It
| keeps time like all old clocks, using the frequency of power. I
| can plug it into a US outlet and it runs, but it runs fast, since
| we're 60Hz here in the US. To remedy this, I bought a 12v power
| supply, and an inverter from Japan that had the 50/60Hz
| selectable on it. I couldn't find any other inverters that had an
| option to run at 50Hz.
|
| I get the feeling that the frequency wasn't checked for accuracy
| / stability, because the clock still eventually goes out of time.
| My KillAWatt shows something like 51 or 49Hz or something like
| that. Not good enough to run a clock.
|
| Been looking for some other way to get 50Hz AC power... This
| seems like it could be promising... but I have no idea how stable
| the frequency will be from a project like this...
| mastax wrote:
| You could use a mechanical 60 to 50Hz converter. Basically a
| motor connected to a generator. They tend to be very expensive
| but maybe there are options.
|
| If I were making something for this problem I would make an AC-
| DC-AC converter with a PLL to divide the 60Hz input frequency
| to 50Hz to control the inverter.
| ilyt wrote:
| > If I were making something for this problem I would make an
| AC-DC-AC converter with a PLL to divide the 60Hz input
| frequency to 50Hz to control the inverter.
|
| I'd put a $3 breakout board with any microcontroller and
| quartz... why would you _want_ to sync to power network in
| the first place ?
| spicyjpeg wrote:
| > If I were making something for this problem I would make an
| AC-DC-AC converter with a PLL to divide the 60Hz input
| frequency to 50Hz to control the inverter.
|
| This is the best way to do it, especially if the synchronous
| motor inside the clock is actually fed with a lower voltage
| from a transformer (which seems to be common in old radio
| clocks as they needed a transformer anyway to power the radio
| circuitry). If that is the case, it should be possible to
| bypass the transformer entirely and build a converter that
| operates entirely on low voltage; some quick searching
| suggests that this exact kind of project has already been
| done before in fact [1].
|
| [1]: https://mitxela.com/projects/phase-locked_inverter
| [deleted]
| jakeinspace wrote:
| Are you positive it's not meant for 100V? That's the standard
| in all of Japan from what I know.
| bob1029 wrote:
| The voltage doesn't affect the time keeping capabilities.
| It's based upon grid frequency. I've got one of those
| US<->Japan xformers I use to run a very special toaster in my
| kitchen. Doesn't do anything for frequency, but that doesn't
| matter in _my_ particular case.
| bob1029 wrote:
| The (presumably) low power demand means you could do pretty
| much anything... you could digitally control the frequency of
| the power to this clock if you ran your own inverter. Like in
| software you would know exactly how many cycles had elapsed
| since previous time and how many need to elapse before the next
| to achieve synchronization with some NTP source. There are all
| sorts of ways you could sort it out, assuming the clock is not
| mechanically slipping relative to AC cycles.
| alwayslikethis wrote:
| It seems quite strange that the clock isn't compatible with
| both 50 and 60 Hz. Japan uses both frequencies in different
| regions.
| thriftwy wrote:
| Fun thing is that inverter is the clock in this case. The time
| keeping device. The wall clock is just a display.
| seabass-labrax wrote:
| What's the power draw of your clock? 50Hz is within the range
| of most LFO circuits (Low Frequency Oscillators) of the kind
| used for modular synthesisers and guitar effect pedals. You
| could combine one of those circuits with a simple voltage
| follower (consisting of a power op-amp or BJT transistor plus a
| couple of resisters) to keep the frequency at a stable 50Hz
| under load, and finally a transformer to convert the signal up
| to 110V.
|
| All in all, I would estimate that this could be done with a
| single IC providing a few op-amps, a handful of passive
| components and a transformer; probably under US$30 or $50 with
| a nice case and plug.
| sigstoat wrote:
| > 50Hz is within the range of most LFO circuits (Low
| Frequency Oscillators) of the kind used for modular
| synthesisers and guitar effect pedals.
|
| i don't think those are designed for long-term frequency
| stability, either. not at the <0.01% level needed for a
| clock. rest of your comment is on track, but the original
| low-voltage low-power 50Hz signal needs to come from
| something that was designed for low long-term drift.
| ilyt wrote:
| Sooooo how much power does that clock use ?
|
| Because simplest one would be:
|
| * a cheapo chinese subwoofer amplifier * 12V wall-wart to power
| it * a quartz-stabilized 50Hz generator (soooo an arduino, with
| DAC, even simple R2R + some filtering). * transformer fitting
| subwoofer amp output voltage. Measure amp output voltage at
| near-max, connect amplifier to secondary and tweak the "volume"
| till it is right.
|
| Sub amp is like $5, $3 for cheapest arduino clone, probably
| like $2 for transformer, and few bucks in proto board and other
| components
|
| If you want to overcomplicate it you could put rPi into it and
| sync the 50Hz clock to NTP
| amluto wrote:
| I have to admit that I _really_ dislike using ~12V batteries for
| high power applications like this. I say this having built a
| ~400A ~14V system. It's miserable.
|
| 1 kW at 100V or 250V or similar uses a nice, small, flexible
| wire. It can be quite safe because it can be fused or otherwise
| protected at low currents, which mitigates the risk of welding
| things, starting fires, or arcing. Ground fault protection, arc
| fault protection, and general loss-of-isolation protection are
| available. It's easy to rework (lever nuts! screw terminals!).
|
| 400A (or even 80A or so like in this article) is a whole
| different ball game. Sure, you have to work hard to electrocute
| yourself. But you can easily set things on fire or weld things
| together without coming close to blowing a fuse. And you need to
| protect _both ends_ of wires in a parallel arrangement. And the
| wires are enormous, expensive, and hard to terminate.
|
| I would much prefer one of three alternative designs to become
| popular:
|
| 1A: a _series_ arrangement of batteries at a civilized 48V or so.
| You can do this with an aftermarket BMS, but they tend to be
| janky.
|
| 1B: same but actually high voltage (a few hundred V, like an EV)
|
| 2: batteries with microinverters and a civilized way to share
| current. A manufacturer could make a single package with a 1kWh
| battery, a BMS, a low voltage, low current DC auxiliary output,
| and a ground-fault and overcurrent-protected 110-250V AC
| input/output. And an RS485 or 10BASE-T1S or CAN connection so
| that they can coordinate their I-V characteristics to appropriate
| distribute charge or discharge current.
|
| Now you can connect as many microinverter-batteries as you like
| in parallel, using #14 wire, to one ordinary circuit breaker per
| battery plus (depending on the overall arrangement) one big
| breaker to protect the common bus.
|
| edit: Also, with this design, no one, not even the manufacturer,
| needs to touch a heavy-gauge wire. Everything in the battery
| would use cheap, painless busbars or small wires, depending on
| the internal voltage, and the manufacturer could set the voltage
| however they like. Although 12V internally might be entirely
| reasonable if the end user also wants to consume 12V at very low
| currents through the aux output.
| RetpolineDrama wrote:
| > 1A: a series arrangement of batteries at a civilized 48V
|
| And here I am mad that home-storage server rack batteries are
| all 48V it seems, but for the same reasons (huge 400+ amp
| cables required to get decent wattages). When each car charger
| can do ~14.4kw you need a lot of fat cables running to battery
| banks
| ilyt wrote:
| > I have to admit that I really dislike using ~12V batteries
| for high power applications like this. I say this having built
| a ~400A ~14V system. It's miserable.
|
| The schematic looks to be pretty adaptable to higher driving
| voltage, just need separate 12V for control board. There is
| even one in datasheet for 24-36V operation
|
| >2: batteries with microinverters and a civilized way to share
| current. A manufacturer could make a single package with a 1kWh
| battery, a BMS, a low voltage, low current DC auxiliary output,
| and a ground-fault and overcurrent-protected 110-250V AC
| input/output. And an RS485 or 10BASE-T1S or CAN connection so
| that they can coordinate their I-V characteristics to
| appropriate distribute charge or discharge current.
|
| > Now you can connect as many microinverter-batteries as you
| like in parallel, using #14 wire, to one ordinary circuit
| breaker per battery plus (depending on the overall arrangement)
| one big breaker to protect the common bus.
|
| You can build it _right now_. AC coupled batteries exist; here
| is some random one that scales up:
| https://www.fortresspower.com/ac-coupled/
|
| The problem is that you generally want batteries when you want
| renewables and in that case just having one big box handling
| batteries and solar panels is more economical than
| microinverters everywhere
|
| 48V battery pack + BMS is significantly cheaper than same thing
| with microinverter, and when you scale up one big inverter is
| cheaper than a bunch of smaller ones.
|
| So yeah, it is "best" but also most expensive way. And frankly,
| the hardest to develop, which is probably why there is little
| to no open designs for that.
| m3kw9 wrote:
| After looking at the instructions, most would rather buy
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