I’m not too happy with their tech support so far. I think they must’ve hired a lot of new people. They don’t seem to have thorough knowledge. I’m not sure I can trust the answers they give me.
DIY or Buy? Charging from generator on dark days or grid down. (48v system)
- Thread starter Mithril
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sunshine_eggo
Happy Breffast!
Read the subject of this thread.
What does that have to do with the price of tea in China? From the very first post and I quote: ”Many (most?) AIO can't charge and invert at the same time.”
Your response was all of them can’t.
sunshine_eggo
Happy Breffast!
You don't get to ignore the context of the information.
Charging from generator
Please show me an AiO that can both charge from generator and invert.
Watts Happening
I call it like I see it.
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I have no horse in this race and I'm not here to start an argument or debate, but this just isn't true.
Victron Multiplus and Quattro units can absolutely charge and invert at the same time. This is a standard feature and they're absolutely "inverter/chargers".
TorC
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How? Where would the energy come from? If it's charging the battery, that means there is more AC power entering the system than is being consumed by loads, and therefore it can't invert from battery without letting out magic smoke. If there's less AC power entering the system than loads are consuming, then it will invert from battery — but there's no power available to charge the battery.
Since thinking in numbers can help, try these:
Generator supplies 2kW, loads consume 1kW: Inverter/charger operates in charge mode, sending the remaining 1kW to batteries. Not inverting
Generator supplies 2kW, loads consume 2kW: Inverter/charger passes 2kW through to loads, sits quiescent otherwise. Not inverting.
Generator supplies 2kW, loads consume 3kW: Inverter/charger passes 2kW to loads, inverts 1kW from battery to not overload generator. This is the only inverting state, and it's not charging.
A simple matter of power flows. It can only do one at a time, because to do both at once would be nonsensical at best, and magic smoke-emitting at worst.
This applies to *all* inverter/chargers and all inverter/charger segments of AIOs. AFAIK, all grid-tie capable inverter/chargers can operate in all three modes. Most (many?) off-grid only inverter/chargers can only operate in the first two.
Correct. The OP wants to use a generator to charge the batteries and also use the batteries to invert to AC.
It is nonsensical as any excess power from the generator could just have gone directly to AC and not through (or to) the batteries to be inverted.
sunshine_eggo
Happy Breffast!
I own two Quattros and can tell you this is is completely false.
They can both invert and charge... just not at the same time.
I cannot think of a time that a unit would be trying to do both at the same time. Either you're pulling from the batteries (inverting) or you're charging the batteries (charging).
If you're using batteries to supplement a load that the AC passthrough cannot support, you're clearly not charging them from the AC. And if you're running on solar, AFAIK in most cases the MPPT is vharging the batteries while the inverter is running the loads.
If you're using batteries to supplement a load that the AC passthrough cannot support, you're clearly not charging them from the AC. And if you're running on solar, AFAIK in most cases the MPPT is vharging the batteries while the inverter is running the loads.
Watts Happening
I call it like I see it.
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I suppose I’m saying the same thing.
The victron units are absolutely capable of accepting a generator input and, “intelligently routing that power as needed in real time”. If there is no major AC demand, they’re charging, as AC demand ramps up they divert charging power to meet the load, if load exceeds generator input they will pull from batteries and assist.
All of which is programmable. That said, I guess what I’m saying is they do what needs to be done, far smarter than picking one or the other.
Vigo
Solar Addict
It is not nonsensical because it divorces the power limit of your load side from the power limit of your generator, and protects all your loads from any hiccups in the AC created by your generator. For this convenience, you 'pay' in extra conversion losses.
Expensive high-stakes UPS's do double conversion by default. Automatic transfer switches often have timers and other conditions before transitioning your loads back to 'grid' because of the large possibility that that AC source is worse than the other one you have. This whole concept is pretty standard and well-established in industry. It is preferable for me to let my 10kw of inverters make up to 10kw of relatively clean AC at a moment's notice, than for me to run 10kw or 20-friggin-thousand-watts of generator ('conventional wisdom' 2x gen sizing) when i can't or don't want to charge my battery bank at 10-20kw to begin with, and if i put a 10kw or 20kw load on it too fast it will stall anyway because it has to mechanically build up to its max power over a MUCH longer time frame than an inverter going from 10w to 10,000w faster than you can snap your fingers. Pure sine inverters are better at making AC than generators are (otherwise they wouldn't put inverters on generators) so.. let them!
My generator feed only has to average more than i consume, to charge the system. It only has to offset my total draw, if that's all im trying to do. But i don't want it directly powering all my AC loads because even in the best case it is irksome. I'd rather pay the extra conversion losses and only worry about what happens on average, over time.
timselectric
If I can do it, you can do it.
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My thoughts are that if paired correctly. A generator and charger can be set up for very good fuel efficiency. Even with the double conversion losses.
TorC
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@Vigo Sure, you can configure for that usecase, but AFAIK, all such double conversion UPSs use *two* separate stages. First a charger stage that produces DC, and second an inverter stage to produce AC. Each one can still only do one job at a time. To my knowledge, there is nothing sold as a whole house/RV/etc. inverter that does that. A hybrid inverter is already designed to synchronize and invert to the grid/gen input line, so they can just do that.
If there were an inverter sold that did double conversion, I'm sure it would be a major bullet point on the sales sheet, probably talking about how it could make use of very AC dirty power and still produce a clean, accurate 60Hz output.
That said, in a major stationary system, you can easily set up your own double-conversion just by installing a separate charger, which has been discussed in this thread, and which has merit in various usecases.
If there were an inverter sold that did double conversion, I'm sure it would be a major bullet point on the sales sheet, probably talking about how it could make use of very AC dirty power and still produce a clean, accurate 60Hz output.
That said, in a major stationary system, you can easily set up your own double-conversion just by installing a separate charger, which has been discussed in this thread, and which has merit in various usecases.
Considering I've got control over when the generator runs (and that it wouldn't be all that hard to do a microcontroller as well) I think that's what I would aim for. It looks like that beefy 100A chargeverter targets ~57V. But my needs are not "get to 100% SOC", hitting 80-90% would be fine
It's not at all nonsensical, read what I laid out and the reasoning. Running a 10Kw generator at 3-4Kw most of the time (Since most AIO, or atleast mine, can't modify charge depending on load, some of the Victrons CAN do that) so that there's enough overhead for all potential loads + some surge is a really really really terrible use of a more more expensive generator I would have to BUY. This would also need to be a high quality inverter generator, which would be louder, heavier, and use more fuel.
Meanwhile with a AC-DC power supply I can tune for fuel efficiency, use the existing generator I have, connect to the dirtiest AC power that will still turn the power supply on if I had to, for way WAY cheaper than buying a new generator. If money was no object I'd have 1MWh of battery capacity and panels on literally every surface to ride out dark days rather than ever have to deal with a generator
Right, thats half of my goal. That and saving money by using what I already have. Between not resisting the battery sales at the end of last year and the price of copper making cables silly, I have not much budget left to allocate to any of this for the time being
I'm actually working on getting more things on DC *anyways* since DC-DC is better than DC-AC-DC (in terms of using battery capacity well)
timselectric
If I can do it, you can do it.
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It's target voltage is whatever you set it at.
Same for amperage.
You choose what SOC you want to reach and how fast you want to get there.
Right, just comparing this threads idea to the commercial product which is basically a high capacity CC-CV "single stage" charger (you set the limits "once" and it doesn't have behavior except staying within those limits). Now it largely looks like a great option, despite a few possible issues (resetting settings when it's powered off? ) but it's 400 bucks
If the chargeverter was out when I started the thread I'd likely have done a "how can I DIY a chargerverter" thread :D
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TorC
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Edit: this was mostly written as a reply to something never intended to be posted, but I think the information may be useful enough that leaving it in the thread is better.
Yes, I've been aware of double conversion UPSs for many years. You pay extra for that and know exactly what you're buying, because it's a beefier inverter and much bigger DC power supply in one, both designed for continuous duty. To my knowledge those UPSs are the only place you find both components in the same box. Anything bigger, and they'd probably just set up some big equipment as separate components to do the job.
The chargeverter is the first entry I've seen into the premade market for a neat box device that fills that niche for the consumer level off-grid/grid backup role. My guess is it'll be a long time before we see a double conversion inverter, especially now that the CV is out. Anyone who has a real use for the isolation probably knows what they're doing.
If we ever see double conversion large inverters in one box, it'll probably be one of two reasons:
1. The first world grid has gone to third world regulation or worse.
2. Privacy geeks are doing it to prevent the utility spying on what devices are running in their house.
As for settings reset, I expect you're watching the testing in that thread, with preliminary results indicating that was probably a fluke and/or bad memory, not normal operation.
Yes, I've been aware of double conversion UPSs for many years. You pay extra for that and know exactly what you're buying, because it's a beefier inverter and much bigger DC power supply in one, both designed for continuous duty. To my knowledge those UPSs are the only place you find both components in the same box. Anything bigger, and they'd probably just set up some big equipment as separate components to do the job.
The chargeverter is the first entry I've seen into the premade market for a neat box device that fills that niche for the consumer level off-grid/grid backup role. My guess is it'll be a long time before we see a double conversion inverter, especially now that the CV is out. Anyone who has a real use for the isolation probably knows what they're doing.
If we ever see double conversion large inverters in one box, it'll probably be one of two reasons:
1. The first world grid has gone to third world regulation or worse.
2. Privacy geeks are doing it to prevent the utility spying on what devices are running in their house.
As for settings reset, I expect you're watching the testing in that thread, with preliminary results indicating that was probably a fluke and/or bad memory, not normal operation.
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