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One of the problems with this approach is that you have to have the gateway managing the grid disconnect. The gateay only supports 200A max feeds, and if you have more than that (we have 400A single phase feed), things get very complicated, esp when the whole house is being backed up.

Part of the issue is how the NEC requires you to count load in a modern home. It's a big house, but we have Mitsubishi VRF style HVAC units that start at 5A and spool up to 35A as load requires, and all the lighting is all LED. We do have an EV, but it only charges after midnight, so we never ever get close to a 400A load. I doubt we'd ever see a real 200A load even when we were maxing out use. We have a 30KW generator and it handles the house easily with room to spare (we don't have the pool equipment on it however)

I can't get tesla to even consider allowing the use of powerwalls in this configuration because of the >200A panel. If they wern't so NIH and allowed the use of a 3rd party ATS, this would be easy to accommodate. Generators have to deal with all of the same sorts of issues and you can find scores of them at different power levels.
 
Okay, what is the status of this?

I currently have a 400 amp service. It goes to a subpanel with a 200 amp and 125 amp breaker. (I had to replace the 200 with the 120 for my solar)

I currently have a 14.5kw solar setup which feeds into a subpanel. I also have a 22Kw generator which feeds into this same subpanel. I have 2 auto transfer switches, one for each subpanel.

All the above works great.

I am now looking at adding some powerwall 2's, maybe 5. From what I gather, a gateway 2 cannot pass 400 amps, so it cannot be connected between the meter and the main panel. So seems next option is to put 2 gateway 2's in, one after each 200 and 125 amp breakers. This feeds my 2 200 amp panels, and if either were to try and draw over 200 amps, the breaker in the main panel blows so no damage to the gateway 2.

I guess I could then hook up batteries to either one of both gateways? Meaning, if the power drops, the gateways would switch off the line. So now everything is electrically connected for use? Solar can power the house or batteries? Batteries can either power the house or being charged or both?
 
Did anyone move forward on the Generator -> AC/DC Converter -> Slave Inverter -> Powerwall charging proposals? I thought I had seen a different discussion on this elsewhere that included another approach, but I am unable to find it. The frequency of extended grid outages is growing and we can absolutely not, in the crisis of climate change, afford to have excess generator capacity not simultaneously charging ANY choice of storage including Powerwalls.
 
Okay, what is the status of this?

I currently have a 400 amp service. It goes to a subpanel with a 200 amp and 125 amp breaker. (I had to replace the 200 with the 120 for my solar)

I currently have a 14.5kw solar setup which feeds into a subpanel. I also have a 22Kw generator which feeds into this same subpanel. I have 2 auto transfer switches, one for each subpanel.

All the above works great.

I am now looking at adding some powerwall 2's, maybe 5. From what I gather, a gateway 2 cannot pass 400 amps, so it cannot be connected between the meter and the main panel. So seems next option is to put 2 gateway 2's in, one after each 200 and 125 amp breakers. This feeds my 2 200 amp panels, and if either were to try and draw over 200 amps, the breaker in the main panel blows so no damage to the gateway 2.

I guess I could then hook up batteries to either one of both gateways? Meaning, if the power drops, the gateways would switch off the line. So now everything is electrically connected for use? Solar can power the house or batteries? Batteries can either power the house or being charged or both?


Lol wow this is like a time capsule... @h2ofun but without Powerwalls or a mega solar array.

BTW did you ever just turn on your liquid-dead-dinosaurs generator and see if your Powerwalls treat that energy as incoming solar generation? Like preferably around dusk so you don't end up exporting a crap-ton of energy.
 
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Unfortunately I doubt Tesla is putting any resources into generator / battery integration. They won’t even sell a Powerwall by itself anymore - only in conjunction with purchase of their PV solar systems. I was lucky to get my PW before the change. I’d suggest looking into Enphase batteries. They will now allow charging of their batteries with select permanently installed generators. But not portable generators (yet?) as the power quality (Total harmonic distortion) from non-inverter portable generators isn’t good enough.
 
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@diyguy I appreciate the reply. Glad you were able to get the PW that you wanted when you did. For the (completely off-grid) user that already has grid tie class inverters, PWs, and inverter class generator, the situation is more about safely recharging the PWs during prolonged periods of little to no sun. It is fully acknowledged that these workaround proposals do not come with the blessings of Tesla, and worse yet, pose a threat to a user's warranty.

As depicted in the above approach in Post #41 would the converter and/or slave inverter sufficiently mute or correct any power quality issues? Previous experience with an older class generator and VFX3648 Outback inverter clearly demonstrated how dirty incoming AC greatly diminished the DC charging capability. That brings up an associated question. Could that Outback inverter be used as the AC -> DC converter. One drawback against this approach is the VFX3648 normally has a 20 amp AC input limit for DC charging, but maybe there is a work around for that as well. I believe the 3600 watt rating of the VFX3648 is closer to 30 amps AC output, so the transformer may be able to handle higher than 20.

Second, the incorporation of the grid-tie inverter would surely seem to give the PWs and needed ability to close off any unwanted power as they approach full charge as well as the needed tasks of syncing frequency (rate and timing).
 
@diyguy I appreciate the reply. Glad you were able to get the PW that you wanted when you did. For the (completely off-grid) user that already has grid tie class inverters, PWs, and inverter class generator, the situation is more about safely recharging the PWs during prolonged periods of little to no sun. It is fully acknowledged that these workaround proposals do not come with the blessings of Tesla, and worse yet, pose a threat to a user's warranty.

As depicted in the above approach in Post #41 would the converter and/or slave inverter sufficiently mute or correct any power quality issues? Previous experience with an older class generator and VFX3648 Outback inverter clearly demonstrated how dirty incoming AC greatly diminished the DC charging capability. That brings up an associated question. Could that Outback inverter be used as the AC -> DC converter. One drawback against this approach is the VFX3648 normally has a 20 amp AC input limit for DC charging, but maybe there is a work around for that as well. I believe the 3600 watt rating of the VFX3648 is closer to 30 amps AC output, so the transformer may be able to handle higher than 20.

Second, the incorporation of the grid-tie inverter would surely seem to give the PWs and needed ability to close off any unwanted power as they approach full charge as well as the needed tasks of syncing frequency (rate and timing).
If you are going to go down this route, I would encourage you to consider getting professional level power quality logging and analysis equipment. Generator power quality is not necessarily stable over time. Given the value of the equipment that you want to connect to the generator buying some quality power logging/analysis equipment is likely to pay dividends over time to identify failing components, it also can help to set up your system in the first place. Unlike the days of Tesla and Edison, modern equipment has lots of active components in their circuitry and the very real potential for odd feedback loops / hysteresis effects to cause significant adverse events. I suspect that many systems are likely to benefit from snubbers, autotransformers, and other devices and designs that attenuate harmonics, voltage, power, and frequency variations.

It may just be me, but I think that hooking up a DC diesel generator to charge some lead acid batteries in a battery bank is one thing. An AC generator coupled to AC energy storage devices with variable and complex loads is a very different class of power control and regulation.

All the best,

BG
 
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If you are going to go down this route, I would encourage you to consider getting professional level power quality logging and analysis equipment. Generator power quality is not necessarily stable over time. Given the value of the equipment that you want to connect to the generator buying some quality power logging/analysis equipment is likely to pay dividends over time to identify failing components, it also can help to set up your system in the first place. Unlike the days of Tesla and Edison, modern equipment has lots of active components in their circuitry and the very real potential for odd feedback loops / hysteresis effects to cause significant adverse events. I suspect that many systems are likely to benefit from snubbers, autotransformers, and other devices and designs that attenuate harmonics, voltage, power, and frequency variations.

It may just be me, but I think that hooking up a DC diesel generator to charge some lead acid batteries in a battery bank is one thing. An AC generator coupled to AC energy storage devices with variable and complex loads is a very different class of power control and regulation.

All the best,

BG
Seems like a lot of effort, cost, etc for what? If my batteries die because of no solar to recharge, I just run my generator. The odds of this happening at all, let alone much is SO low, .... Sounds cool, but KISS
 
@diyguy

As depicted in the above approach in Post #41 would the converter and/or slave inverter sufficiently mute or correct any power quality issues? Previous experience with an older class generator and VFX3648 Outback inverter clearly demonstrated how dirty incoming AC greatly diminished the DC charging capability. That brings up an associated question. Could that Outback inverter be used as the AC -> DC converter. One drawback against this approach is the VFX3648 normally has a 20 amp AC input limit for DC charging, but maybe there is a work around for that as well. I believe the 3600 watt rating of the VFX3648 is closer to 30 amps AC output, so the transformer may be able to handle higher than 20.

Second, the incorporation of the grid-tie inverter would surely seem to give the PWs and needed ability to close off any unwanted power as they approach full charge as well as the needed tasks of syncing frequency (rate and timing).

Do you already have a PW? If not, you should just look at alternatives that allow grid and generator charging.

The approach in Post #41 is unlikely to work well. Grid-tied inverters often don't work well with common DC voltage source power supply units (i.e. AC-DC converters). One main reason is that most GTI have MPPT and the they often don't work well with DC voltage sources. If you want to try then you should use a DC current source power supply which is less common especially high power ones.

Not sure if anyone has tried it but a more straight forward approach for black start (i.e. recharge a drained PW without the grid) would be to to use a large 240VAC pure sine wave off-grid inverter/generator (>7kW continuous for 1 PW) feeding the house via a transfer switch with the grid, GTI solar and all loads disconnected.
 
For the (completely off-grid) user that already has grid tie class inverters, PWs, and inverter class generator, the situation is more about safely recharging the PWs during prolonged periods of little to no sun.
@h2ofun with all your infrastructure, are you grid-tied? We are not, and running the generator just for loads is contrary to our goals. It may be very low odds for it happening for you with 30kw generation and 5PW storage. Our 11kw and 2PW is ALL the non-generator we have. Ultra-conservation is not new to us nor a rarity.
 
@h2ofun with all your infrastructure, are you grid-tied? We are not, and running the generator just for loads is contrary to our goals. It may be very low odds for it happening for you with 30kw generation and 5PW storage. Our 11kw and 2PW is ALL the non-generator we have. Ultra-conservation is not new to us nor a rarity.
Am grid tied. In the winter, or even summer, I would run out of batteries in less than a day if no decent solar.
 
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@BGbreeder thanks for the input. Though not the latest technology, we recently obtained a Fluke 43b PQA for logging PW frequency behavior before and during curtailment, trying to capture the occasional 65+hz shutting down solar harvesting. (We have not contacted Tesla to have this adjusted.) We also hope to compare voltage logs against the fluctuations that are showing up on the Sense Home voltage graphs. We have not yet looked at power for the system though briefly at harmonics. We have not yet looked at the generator's output. Two limitations (at least) of this meter is it only one voltage input (as per instructions), though I have a ticket into tech asking whether the amp probe input can be used for L2 when assessing 240. Also the i400s current clamp is AC only, so I can't use it to watch Hz against DC amps during solar curtailment. The 801-110s DC clamps are a bit pricey to buy just for that task.

@cali8484 would using the Outback VFX3648 for AC->DC and 'buffering' the DC with a battery (the old Surrette 48V set) address any of the GTI complaints regarding the source DC?
Second as to recharging PW with 240 PSW inverter/generator, is that scenario manually controlling end-of-charge generator shut down?
 
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What happens when you run your generator? Would it run your whole house and maybe even charge the powerwalls if the generator feeds your solar generation panel?
The generator is hooked up to two ATS. It can only engage if there is NO power, whether the grid or batteries, it cannot tell. So when it engages it disconnects all the upstream sources

Yes, at 22K, it can run the entire house with no effort.

Generator can never see the solar or it would damage it, and probably the generator, so the ATS again makes this impossible.
 
@h2ofun with all your infrastructure, are you grid-tied? We are not, and running the generator just for loads is contrary to our goals. It may be very low odds for it happening for you with 30kw generation and 5PW storage. Our 11kw and 2PW is ALL the non-generator we have. Ultra-conservation is not new to us nor a rarity.

With how hot it is now, summer actually seems worst for my solar/storage energy use situation. I don't generate much more solar now vs. Winter due to summer gloom (cloudy till 9), but use tons more of power now.

During the sunny winter months, I'd generate like 40 kWh or so and use < 20kWh everyday (no need for AC). Now, I generate like 45 kWh or a bit more, but can use 40-50kWh if I decide to charge the EV that day.

I think if someone tried to live comfortably in all seasons, you cannot really rely on only solar/energy storage (batteries) due to multiple cloudy days or fires (in CA). Best off grid is still probably generator, big propane tank (for heat and maybe support the generator too if it takes propane) and more solar panels/batteries.

h2ofun runs his house at 70 I think when it's 95 outside. He uses 50kWh+ a day minimum :) so his batteries aren't going to last long.
 
The generator is hooked up to two ATS. It can only engage if there is NO power, whether the grid or batteries, it cannot tell. So when it engages it disconnects all the upstream sources

Yes, at 22K, it can run the entire house with no effort.

Generator can never see the solar or it would damage it, and probably the generator, so the ATS again makes this impossible.


Awwww dang, ok so there's no way to open your solar disconnects (like I hope you have lots o them), close your ATS circuit, and push generator power onto your generation panel thereby charging Powerwalls and powering your house?
 
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@h2ofun with all your infrastructure, are you grid-tied? We are not, and running the generator just for loads is contrary to our goals. It may be very low odds for it happening for you with 30kw generation and 5PW storage. Our 11kw and 2PW is ALL the non-generator we have. Ultra-conservation is not new to us nor a rarity.
Wait, you are not connected to the utility grid at all?

If you are fully disconnected from the grid, then I do not understand why not follow Tesla off grid guidelines? Tesla has generator support for these homes, and the TEG can trigger the generator to start, recharge the batteries, and serve loads all at once.

Maybe I am missing something and you are just connected to a very bad grid?