DIY or Buy? Charging from generator on dark days or grid down. (48v system)

[Mithril]

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.

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

 

[Mithril]

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.

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]

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 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.

 

[Mithril]

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

 

[TorC]

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.

 

[timselectric]

Now it largely looks like a great option, despite a few possible issues (resetting settings when it's powered off? )

That doesn't seem to be the case. I previously thought it was. But further testing (personally confirmed) has shown that it retained the settings.

 

[Mithril]

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.

I think I started a reply, changed my mind, came back to reply to someone else and it got remembered. Sorry about that! Edited my reply to remove since I had re-read your comment (and thats why I changed mind about replying realizing I missed what you said lol)

Anyways, for the usecase I'm thinking of this wouldn't be on 24/7, just to charge from gen when grid down and not enough solar.

Yeah, watching the thread since I don't remotely have a use for a 100A charger (yet) so it feels hard to justify the price *for me* (not saying bad value for what it is, just that I would be vastly under using it)

 

[TorC]

Technology. Can't live with it, can't live without it, but it's gotten to the point where it acts at least as much to autocorrupt as it does to autocorrect. Cheers!