You do not have to hook to the grid IF you have batteries. Something has to power the unit and that is either the grid or battery. The PV will come into play but to boot it up and make it work its best to have grid or battery. Either one will work.
Question About Preventing Grid Backfeed
- Thread starter jeff88
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Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
I don’t understand why SUB mode would be preferred over SBU.. to not pay for power from the grid the U shouldn’t be used till S and B are depleted or B reaches a settable preferred disconnect voltage. So is that the only way your setup will utilize the grids power and DC at the same time,,? When it’s in SUB mode? Not when it’s in SBU mode.
I don't have my 10kw unit yet (it gets here friday) but on my tp6048 in sub mode it keeps the battery charged while running off solar for whatever it can and supplementing from the grid for what it can't get from solar.
In sbu mode it run on solar and then gets what it needs from the battery and if the battery gets to low it draws from the grid and charges the battery at the same time.
In sbu mode it run on solar and then gets what it needs from the battery and if the battery gets to low it draws from the grid and charges the battery at the same time.
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
I think u want a setup similar to mine. It’s sized to only cover constant high loads. When loads rarely exceed my highest constant high loads the grid simply supplies only the rest of what the homes loads need that my inverters aren’t already covering. With this type of setup, Yes backfeed into the grid when loads shutoff is unavoidable. My utility company simply required an and agreement and inspection by our local electrical inspector who (to say the least) was unfamiliar with solar setups. Easily passed inspection. Only requirements was an outdoor solar disconnect. The agreement basically only confirmed that I didn’t want compensation for any backfeed..
Having the type of setup I have IMO is the best way to do it since the grid is a very good backup power source and since I wasn’t trying to take my entire house offgrid. Monthly Electric bill is basically just the $27 fee to have the utilities power connected to my house.
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
Right so it will not allow the loads to utilize the battery and the grid simultaneously. For example if the inverter can only possibly supply a maximum of 6000w at night from battery and loads exceed that 6000w (let’s say 9000w) will the inverter allow the loads to use battery for 6000w and grid for the other 3000w simultaneously? I suppose not
If there is enough solar to power the loads and have some left over it will charge the battery with the grid and solar at the same time.
If the battery depletes completely it goes to sub mode and charges the battery. I haven't let it exceed the 6k max so no clue. I know @42OhmsPA has run his past the limit so he would have to chime in on that.
timselectric
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It normally isn't.
It's only useful when you have no battery. Or a very small battery.
SUB mode is there so that it can operate batteryless.
timselectric
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In SBU mode it will use solar and battery together. And switch to grid as a backup if needed.
In SUB mode it will use solar and grid together. And switch to battery as a backup.
Grid and battery together is never a possibility. (always either/or )
42OhmsPA
What's in a title?
I had grid breaker off when I really started pushing the tp6048.
When grid was on and I overloaded it, it would bypass to utility.
I primarily ran in SBU, unless I force charged before a storm.
My 10KW ASP's will not have a grid connection, I'll be using a power rectifier to the DC bus for supplemental charging.
wpns
Solar Joules are catch and release
I'm doing a "Modified TimsElectric" setup, two chargeverters with the inputs enabled by relays from the dry generator contacts with the generator charge set to start at 10% and stop at 50%. Hasn't happened yet, but I'm expecting it'll kick in after a cloudy day or two with a full house, and I'll buy $25 worth of electricity without even noticing.
I didn't do the "Full TimsElectric" (float at 48V) thing because my loads have been as high as 20KW, and I don't want to run my batteries down too low. Also I can unplug the CVs from the wall and use a couple of generators if the grid fails.
I tested the new Smart Meter the PoCo installed, and it turned out it's programmed for "Security" mode, where it charges me the same amount for positive and negative power (just adds them up internally and displays a singe number). So I pushed 1.6KWHR into the grid and paid a buck for the privilege. Lesson learned, back to off-grid mode with purchased power through the CVs as required. We'll see how it goes and modify as required (and maybe add another pair of PP batteries), but so far except for testing I haven't bought a single KWHR.
I didn't do the "Full TimsElectric" (float at 48V) thing because my loads have been as high as 20KW, and I don't want to run my batteries down too low. Also I can unplug the CVs from the wall and use a couple of generators if the grid fails.
I tested the new Smart Meter the PoCo installed, and it turned out it's programmed for "Security" mode, where it charges me the same amount for positive and negative power (just adds them up internally and displays a singe number). So I pushed 1.6KWHR into the grid and paid a buck for the privilege. Lesson learned, back to off-grid mode with purchased power through the CVs as required. We'll see how it goes and modify as required (and maybe add another pair of PP batteries), but so far except for testing I haven't bought a single KWHR.
dougbert
Solar Wizard
I like it
timselectric
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Surely that's not your continuous load.
What's your daily average kwh?
Two chargeverters can supply 240kwh every day.
Maybe float at 50v?
Still working through this. Trying to keep costs down while maintaining a set-it-and-forget-it power system. Can't have wife and kids upset because I was messing around with my project! 
Looking at SS's website they have several panel options. The Adani 530W mods caught my eye, but haven't made a decision yet.
My inverter options in the price range I'm looking for seem to be limited. I can use the Growatt 10 or 12kW (this one caught my eye because SS has an as-is one for significantly cheaper). There is also the Sungold 10kW and the PowMr 10kW. I know there are other re-branded ones too. Not sure if any of these options are better than the others, as it seems like people here either like them or wouldn't even try them (and haven't).
For the chargeverter, it would be nice to have that grid support when necessary, but in the interest of budget I'm thinking I might skip that for now and build into that. I don't expect the inverter to have to switch to utility too often given our usage history so I think I can save the funds towards another future battery if needed, especially if the EG4 chargeverter is half the cost of another battery.
Looking at SS's website they have several panel options. The Adani 530W mods caught my eye, but haven't made a decision yet.
My inverter options in the price range I'm looking for seem to be limited. I can use the Growatt 10 or 12kW (this one caught my eye because SS has an as-is one for significantly cheaper). There is also the Sungold 10kW and the PowMr 10kW. I know there are other re-branded ones too. Not sure if any of these options are better than the others, as it seems like people here either like them or wouldn't even try them (and haven't).
For the chargeverter, it would be nice to have that grid support when necessary, but in the interest of budget I'm thinking I might skip that for now and build into that. I don't expect the inverter to have to switch to utility too often given our usage history so I think I can save the funds towards another future battery if needed, especially if the EG4 chargeverter is half the cost of another battery.
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42OhmsPA
What's in a title?
I just hit 6MWh of solar production through my 10KW today.Still working through this. Trying to keep costs down while maintaining a set-it-and-forget-it power system. Can't have wife and kids upset because I was messing around with my project!
Looking at SS's website they have several panel options. The Adani 530W mods caught my eye, but haven't made a decision yet.
My inverter options in the price range I'm looking for seem to be limited. I can use the Growatt 10 or 12kW (this one caught my eye because SS has an as-is one for significantly cheaper). There is also the Sungold 10kW and the PowMr 10kW. I know there are other re-branded ones too. Not sure if any of these options are better than the others, as it seems like people here either like them or wouldn't even try them (and haven't).
For the chargeverter, it would be nice to have that grid support when necessary, but in the interest of budget I'm thinking I might skip that for now and build into that. I don't expect the inverter to have to switch to utility too often given our usage history so I think I can save the funds towards another future battery if needed, especially if the EG4 chargeverter is half the cost of another battery.
A member also posted a recent DDP quote of ~$1200 for the one they ordered.
Personally I'd go with the OEMs to keep cost down, Growatt is a reputable OEM, SRNE is another one based on my experience and other users reports.
I know some members have been running Growatts longer than I've been a member.
If you want to keep the DC charger costs down pick up a used power rectifier ~$100 for 3KW charging and minimal DIY effort.
On the topic of set it and forget it, some heavy storms rolled through earlier. I got a phone call from my power company shortly after letting me know power should be restored by 2AM, awhile later another call that it will be by 11PM tomorrow and thousands of customers are affected.
I had no idea until I got the call...
I went out to snack in the garden and the neighbors generator was just humming along, they have 2 roofs covered in panels. One of these days I'll suggest a battery backup to them ...
6Mwh is fantastic!
Do you have the link to that thread for the quote?
I'm seriously considering the Growatt. Going to contact SS tomorrow.
Got any links to get me started in the right direction for the rectifier?
A friend of a friend got a couple of power walls and when the grid went down he didn't even know until a friend called and ask to use the oven to finish baking their pie!
42OhmsPA
What's in a title?
Most recent post with quote.
Link to store and other info.
Pinging @1201 for the Growatt guru..
This will get you started. That thread is huge and has a ton of great info on going really advanced with voltage control. I'll get there eventually, for now I have one with a safe voltage that I can just wire up and use.
That's awesome.A friend of a friend got a couple of power walls and when the grid went down he didn't even know until a friend called and ask to use the oven to finish baking their pie!
1201
Solar Wizard
sadly I know less than zero about growatt offgrid inverters
What is your experience with them in general? Would you be willing to buy a refurbished one from SS or would you steer clear?
wpns
Solar Joules are catch and release
I don't know how long that 20KW lasted, but it was a decent confirmation that I needed a pair of 18Kpv inverters. Average is around 85KWH/day, though it's only been a week. 6 guests arriving this weekend, so we'll be giving it a real workout soon, and I expect to be buying power, if only to test my algorithm.
timselectric
If I can do it, you can do it.
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Sounds like two your chargeverters wouldn't have any problems keeping up.
If you wanted to go that route.
Hey WPNS do you have a schematic or full write up on your system? Looking to duplicate your system at my house
Where would you put them? The other side of that wall? The ones you’ve already got are blocking access to your inverters and adding more would block access to your AC panels too. I assume you’re not subject to NEC 110.26.
wpns
Solar Joules are catch and release
The fisheye lens makes it look more crowded than it is. Another pair will fit comfortably in front of those, but additional pairs could very well go on the other side of that wall. Still contemplating if we need more, going to give it some more exercise.
The six houseguests were a real test of the system, we bought power every day but only 50-ish KWHR the whole time, so unless we open a BNB it’s probably not going to happen soon. Of course, we do have ‘range anxiety’ when on a ‘normal’ day the battery hits a low of 40%.
wpns
Solar Joules are catch and release
No, but I could look at it when my Round Tuit arrives.
It’s not actually rocket science, on the grid there are two 30 amp breakers that go down to some junction boxes where the relays are mounted. The relay contacts are used to turn the AC power on and off to the plugs that the ChargeVerters are plugged into.
https://a.co/d/0dEznVqk For the relay I used, but there are lots of options.
The 120V relay coils have (grid) L1 on one side, and the 18Kpv Generator Dry Contact switches the other side to Neutral to enable the input power to the CVs when the inverter calls for generator operation.
It was working just fine until I foolishly turned on the grid power (even though I am in off grid mode, I wanted to log the grid data so I can know when my neighbors are out of power), which caused the generator dry contacts to stop working.
The Gen dry contacts appear to be working now, but I am leaving for hurricane season and I don’t want to make any changes just before I leave. I’m going to leave the system in “float“ mode, where the CVs are powered continuously, and are set to a voltage corresponding to about 25% SOC. It doesn’t do exactly what I want, but it’s not awful until I get a chance to get back and rewire everything and test it thoroughly.
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