dickson Posted May 28, 2022 Share Posted May 28, 2022 Sean live chat say he only run off-grid for one hour at night with battery . I have over 40 kwh lithium ion battery and still need to recharge at night . Battery cost more than any inverter or solar panel and the copper wires needed makes complete off-grid too expensive for me . 1 Quote Link to comment Share on other sites More sharing options...
TheButcher Posted May 28, 2022 Share Posted May 28, 2022 I'm guessing you have a fair amount resistive heating, both room and water, and several people in the residence? Quote Link to comment Share on other sites More sharing options...
dickson Posted May 28, 2022 Author Share Posted May 28, 2022 I can not run a heat pump on battery but run a large 1 hp 240vac swamp cooler on continously in the summer and refrigerator and freezer . I have to rechage one third of the battery at the same time I am using the other two third of the baatery to run the inverter off-grid at night . The problem is I only have 6000 kw of solar panel to charge two third of the battery during the day . The battery is only usable from 62 volt to 46 volt . I will need another 20000kwh of battery or 60000 kw of solar panel which is impossible to hide in the backyard with 7 palm trees blocking the sun . One man a few miles from me hide 60000 kw of solar panel in his backyard and use a 12kw inverter with built-in MPPT solar controller to run his heat pump 12 hours a day using only solar panel and 4 AGM battery . Quote Link to comment Share on other sites More sharing options...
RobertM Posted May 28, 2022 Share Posted May 28, 2022 (edited) I have 1/10 of the battery storage that you have. It is 2.4 kwh of LiFePO4 batteries and about 2.4 kwh of flooded batteries which cannot discharge as deeply. There is a new experimental battery technology in development that uses a molecule of carbon, hydrogen and nitrogen that can change shape and become energy-rich when exposed to sunlight. It can be stored, as a liquid, for years, and can release stored energy on demand, in the form of heat. https://lithium-news.com/a-breakthrough-in-solar-energy-storage/ Edited May 28, 2022 by RobertM Quote Link to comment Share on other sites More sharing options...
NotMario Posted May 28, 2022 Share Posted May 28, 2022 (edited) I run off grid 24/7 with 10KWH. No AC needed here and heat is powered by diesel. Most consumption is idle draw from misc devices and freezers. The only difficult component to deal with is the electric drier. Thankfully the GS is very reliable. 3000 hours already and nothing to complain about. FYI, you can buy ~2.5KWH of LiFePO4 for ~350$. (everything already done for you - just hook up) It's not really that expensive when appropriately sized... Edited May 28, 2022 by NotMario Quote Link to comment Share on other sites More sharing options...
dickson Posted May 29, 2022 Author Share Posted May 29, 2022 20000kwh of battery or 60000 kw of solar panel Suppose to be 20000 watt hour of battery or 60000 watt of solar panel . Thank you . Quote Link to comment Share on other sites More sharing options...
dickson Posted May 29, 2022 Author Share Posted May 29, 2022 FYI, you can buy ~2.5KWH of LiFePO4 for ~350$. (everything already done for you - just hook up) It's not really that expensive when appropriately sized. My 5 MSB 60A solar charge controller is set at 66volt so LiFePO4 will not match . Used lithium ion BMW car battery is 300 dollars each include shipping tor 2.0KWH which is what I am using . If I get 10 more then I can be off-grid at night but the Delta fan sound like a jet engine in my back yard so maybe still not be completly off-grid because of the noise . Quote Link to comment Share on other sites More sharing options...
dickson Posted May 29, 2022 Author Share Posted May 29, 2022 I have 1/10 of the battery storage that you have. It is 2.4 kwh of LiFePO4 batteries and about 2.4 kwh of flooded batteries I started 3 years ago with 4 kwh AGM battery that is till being use every day . I use a special AGM charger to keep it like new . I also had LiFePO4 batteries but in the begining I let it discharge too low and is damage . At the time I know nothing about charging battery . Quote Link to comment Share on other sites More sharing options...
InPhase Posted May 29, 2022 Share Posted May 29, 2022 It can be done but it can't be done with an on-grid lifestyle. You have to change how you live in most aspects. So do laundry during the day. Run the air conditioner hard when the sun is shining and get the house chilled and coast through the night. Put a timer on the ghost loads so they turn off while you're asleep. The electric water heater shouldn't be allowed to cycle after dark either. Etc. 3 1 Quote Link to comment Share on other sites More sharing options...
dickson Posted May 29, 2022 Author Share Posted May 29, 2022 It can be done but it can't be done with an on-grid lifestyle. You have to change how you live in most aspects. I can live off-grid on solar and battery . My wife get mad when the house is hot and do not care how much the heat pump cost in electric usage . It is over 100 degree every day now and next month it will be over 100 degree all night . I uae to grow over 100 pounds of squash in my backyard but now nothing grow but bermuda grass and russian giant sunflowers . Quote Link to comment Share on other sites More sharing options...
dochubert Posted May 31, 2022 Share Posted May 31, 2022 On 5/29/2022 at 6:47 AM, InPhase said: It can be done but it can't be done with an on-grid lifestyle. Words to live by, ...literally! We have a very large battery bank (lifepo4) and more than enough solar to keep it charged and run the house 24/7 from late March to late October (usually!) The exceptions are the electric dryer and the central AC, both of which run when needed only on grid power. My 15kw powerjack can't run either one reliably so they are only grid connected. (The powerjack is really just a decent 6kw, ya know) My wife hangs the laundry out in good weather (most all the time march to october) and the central AC unit is typically only needed a couple of weeks per summer. The oven is used in the daytime and she tries to limit its use to sunny days. The microwave is not enough to worry about. Two freezers and a large refrigerator, plus a well pump are the normal larger loads. When we have consecutive rainy days (like right now!) I have to keep an eye on things but there is usually enough solar to get by on without switching to grid. If my wife really wants to use the oven on a cloudy day I can always switch it to grid for the time she's using it. The water heater has its own battery bank (also lifepo4), solar to charge it, and an 8kw (realistically a 3kw) powerjack that only runs the water heater in powersave mode. The 8kw has a timer to limit it's running to daytime hours, a protection circuit to allow it to run only when the batteries are in proper voltage range, and it has been running winter and summer non-stop for nearly 2 years, providing hot water for my wife and I. Between October and March if there's enough sun I run the house on the powerjack during the day and switch to grid overnight. Sadly I have to use grid power a lot in december (shortest days). I could run on batteries more than I do in winter but I'm trying to preserve my battery life by going easy on them. Someday soon there might be no grid to switch to, then we're all on our own, like it or not. 3 Quote Link to comment Share on other sites More sharing options...
RobertM Posted June 6, 2022 Share Posted June 6, 2022 On 5/30/2022 at 8:34 PM, dochubert said: Words to live by, ...literally! We have a very large battery bank (lifepo4) and more than enough solar to keep it charged and run the house 24/7 from late March to late October (usually!) The exceptions are the electric dryer and the central AC, both of which run when needed only on grid power. My 15kw powerjack can't run either one reliably so they are only grid connected. (The powerjack is really just a decent 6kw, ya know) My wife hangs the laundry out in good weather (most all the time march to october) and the central AC unit is typically only needed a couple of weeks per summer. The oven is used in the daytime and she tries to limit its use to sunny days. The microwave is not enough to worry about. Two freezers and a large refrigerator, plus a well pump are the normal larger loads. When we have consecutive rainy days (like right now!) I have to keep an eye on things but there is usually enough solar to get by on without switching to grid. If my wife really wants to use the oven on a cloudy day I can always switch it to grid for the time she's using it. The water heater has its own battery bank (also lifepo4), solar to charge it, and an 8kw (realistically a 3kw) powerjack that only runs the water heater in powersave mode. The 8kw has a timer to limit it's running to daytime hours, a protection circuit to allow it to run only when the batteries are in proper voltage range, and it has been running winter and summer non-stop for nearly 2 years, providing hot water for my wife and I. Between October and March if there's enough sun I run the house on the powerjack during the day and switch to grid overnight. Sadly I have to use grid power a lot in december (shortest days). I could run on batteries more than I do in winter but I'm trying to preserve my battery life by going easy on them. Someday soon there might be no grid to switch to, then we're all on our own, like it or not. How deeply do you discharge your LiFePO4 batteries? As low as 20%? Quote Link to comment Share on other sites More sharing options...
dickson Posted June 7, 2022 Author Share Posted June 7, 2022 How deeply do you discharge your LiFePO4 batteries? As low as 20%?According this youtube he say do not discharge to 2.5 volts but discharge to 3.1 volts . LiFePO4 batteries has a flat discharge curve and 2.5 volt will damage the battery . Busting the 20%-80% SOC myth for LiFePO4 batteries. Jun 2, 2022 Quote Link to comment Share on other sites More sharing options...
TheButcher Posted June 8, 2022 Share Posted June 8, 2022 (edited) I saw that clip from Andy. The only thing he busts there is the method less experienced (?) people try to do 80/20 cycling with, voltage monitoring. 80/20 cycling absolutely improves lifepo4 cycle count and he does attempt to disprove that either. There's plenty of research out there about it going back decades (yes, lifepo4 is quite old). Edited June 8, 2022 by TheButcher Quote Link to comment Share on other sites More sharing options...
NotMario Posted June 8, 2022 Share Posted June 8, 2022 On 6/6/2022 at 3:17 PM, RobertM said: How deeply do you discharge your LiFePO4 batteries? As low as 20%? With LiFePO4s, they actually tend to dislike being fully charged. For myself, i try to keep SOC between 75% to 25%. So Depth Of Discharge is somewhat of a different concept compared to Lead Acids. It's not merely a "50%" or "100%" anymore, it's a SOC range; 100-40 will result in [significantly] shorter cycle life than 70-10, even though they both grant 60% capacity. 14 hours ago, TheButcher said: I saw that clip from Andy. The only thing he busts there is the method less experienced (?) people try to do 80/20 cycling with, voltage monitoring. 80/20 cycling absolutely improves lifepo4 cycle count and he does attempt to disprove that either. There's plenty of research out there about it going back decades (yes, lifepo4 is quite old). Yeah... SOC shunt is an absolute must. The science is pretty clear. LiFePO4's are mildly damaged when fully charged, a chemical reality much the same as how 0% will kill them. 1 Quote Link to comment Share on other sites More sharing options...
dickson Posted June 9, 2022 Author Share Posted June 9, 2022 We have a very large battery bank (lifepo4) and more than enough solar to keep it charged and run the house 24/7 from late March to late October (usually!) The exceptions are the electric dryer and the central AC, both of which run when needed only on grid power. My 15kw powerjack can't run either one reliably so they are only grid connected Thank you for showing how you go off-grid as I was sure I had enough battery power of over 40000 watts to go off-grid 24/7 . I been off-grid 24/7 for the last 4 days doing what you do . I can use the washer but not the electric dryer . I hang the clothes outside and not use the water heater . NO heat pump and set the swamp cooler at 86 degree when the temperature is over 100 degree every day and it was 111 degree yesterday . Use the microwave amd air fryer but NO oven . Use LED for lights . Quote Link to comment Share on other sites More sharing options...
dochubert Posted June 9, 2022 Share Posted June 9, 2022 I haven't tried to figure the percentage. From March to October, running 24/7 the batteries never drop below 52 volts after running the house overnight. Even after one very cloudy day or multiple partly cloudy days. On sunny days the overnight drop is only to about 52.5v. It's a very large bank. 16 BYD 24v 220ah modules configured for 48v. They weren't new when I got them so I try to use them without pushing them overmuch. If they will be dropping below 52 volts overnight because of long nights or bad weather(poor charging previous day) I just switch to grid overnight. Sometime in october I usually start doing that daily. By winter solstice I have to stay on grid most of the time. Winter days are just too short here, and many of them have little sun. By february I'm usually running daytime and switching to grid overnight. Then sometime in March I can start 24/7 running again straight through to late October. So no lower (usually) than 52v and float is set to 56v, so that's my range. Quote Link to comment Share on other sites More sharing options...
dickson Posted June 9, 2022 Author Share Posted June 9, 2022 It's a very large bank. 16 BYD 24v 220ah modules configured for 48v. I think that is over 80000 watt hour . That is the amount of battery Sean say he need to run his 5000 sq ft house 24/7 . Sean say he has less than 10000 watt hour of battery and can only run one hour at night . My BMW car battery run between 64 v to 46 v on a 15kw Powerjack that is 3 years old . I can run 24/7 now . Quote Link to comment Share on other sites More sharing options...
TheButcher Posted June 9, 2022 Share Posted June 9, 2022 The amount of energy you guys are burning through makes me almost embarrassed to say that even if I try I can only expend about 7kWh across a whole day. That includes standard resitive water heating and an aircon in heating mode running all night maintaining 21c and .. an electric blanket to make my old joints happy since the overnight temp has been around 7c lately. Quote Link to comment Share on other sites More sharing options...
dickson Posted June 9, 2022 Author Share Posted June 9, 2022 The amount of energy you guys are burning through makes me almost embarrassed to say that even if I try I can only expend about 7kWh across a whole day I can not explain why dochubert and Sean and ME need so much battery . Maybe 240 vac single phase need less battery ? Quote Link to comment Share on other sites More sharing options...
TheButcher Posted June 9, 2022 Share Posted June 9, 2022 kWh is kWh. The batteries do need to be sized to cope with peak draw and then some to avoid flogging them but that aside... It would be interesting to see some real world measurements of where all the power is going if for nothing more than satisfying curiosity. Quote Link to comment Share on other sites More sharing options...
dickson Posted June 11, 2022 Author Share Posted June 11, 2022 The batteries do need to be sized to cope with peak draw and then some to avoid flogging them but that aside... It would be interesting to see some real world measurements of where all the power is going if for nothing more than satisfying curiosity. I will now do the math to show why I will NOT get a 12 kw sigineer and expect to run the whole house 24/7 with the 42000 watt hour of BMW car battery I have . 12,000 / 0.88 = 13,636W input for 12kw output. That's 1,636W of heat generated at full nameplate. SID say I'm sorry, but a little quiet 80mm muffin fan ain't gonna get 1,636W out of an inverter! And of course, the hotter the transformer gets, the higher the losses go (due to the thermal resistivity of the wiring). At night I must charge the BMW battery at the same time I am using the battery because my solar can not charge all the battery during the day . I am using 10 e-bike charger at 4 amps and 65 volts which is 2600 watts very hour . This 31200 in 12 hours so only 11000 left of the 42000 watt hour of battery . The sigineer has 250 watt idle times 24 hour is 6000 watts so now only have 5000 watts left to run the whole house for 24 hours but have to subtract 1,636 W and that leave 3364 watt to run my house . NOW running my house from the sigineer 12kw with 3384 watt of battery left is NOT going to work . I am able to run 24/7 yesterday with my 15kw PJ and the temperature is a high this year at 112 degree F and the concrete in the patio is 130 degree F . The Delta fans sound like a 747 flying overhead all day . Quote Link to comment Share on other sites More sharing options...
TheButcher Posted June 11, 2022 Share Posted June 11, 2022 Your logic / thought paths are about as broken as a PJ 🙂 You can't pull 15kw from the PJ at all. You probably can't sustain 12kW from the Sigineer either but it might get there for a while. The Sigineer might have an idle draw of 250W, where did that come from? The PJ has idle draw too but you don't account for that. You only subtract that 1.6kW of power with the Signeer at full tilt and it probably can't sustain that anyway. If you draw 8kW at 88% efficiency your waste is 1.1kW, ie total load is around 9.1kW. You can't both charge and discharge a battery. It's one or the other. It might oscillate back and forth but it's still one or the other. If you are having to put 2.6kW in via a wall of ebike chargers you have made a fundamental design error with your system. Fix the PV side so that your production is commensurate with your expected load or run at least part of your load direct of the AC supply that you are using to run the chargers instead of the chargers into the battery into the inverter. It'll be more efficient not having to go through multiple voltage conversions and thereby cheaper no matter what the underlying source - grid or generator. The only way the above response doesn't work is if what you stated is not what you are actually doing or is so confusingly stated that it makes a reasonable reply impossible. 1 Quote Link to comment Share on other sites More sharing options...
dickson Posted June 12, 2022 Author Share Posted June 12, 2022 You can't pull 15kw from the PJ at all. You probably can't sustain 12kW from the Sigineer either but it might get there for a while. The Sigineer might have an idle draw of 250W, where did that come from? This 250 W of idle draw come from your post in another topic today . 6 hours ago, TheButcher said: The high idle draw of even the lower wattage Chinese inverters is a problem. 80 watts is about 2kWh a day and that's a fair slice of the production of a small system. yes, on a whole house system running a large inverter which is never at idle ,,,,, a Sigineer 18K LF inverter with 250 watt standby idle would not be as big a problem in a large solar panel system with a big battery bank, but still a bit of wasted solar power... so more panels needed.... Sorry I know my PJ 15 kw can only pull 4000 watt with the rev 11.1 control board . I never has a sigineer 12 kw or seen test on it . I was making a (what if ) statement or posting what happen with a high idle draw inverter like a sigineer 12 kw . MY logic / thought paths are about as broken as a PJ 🙂 The only way the above response doesn't work is if what I stated is not what you are actually doing . Quote Link to comment Share on other sites More sharing options...
TheButcher Posted June 12, 2022 Share Posted June 12, 2022 Nope. I did not say that and the post you linked to does not show me saying 250W it shows... 80W for lower wattage Chinese inverters. Neither does PilgrimValley's post. The person that did say it was inPhase. Probably best that you don't attribute one person's post to another. 🙂 Quote Link to comment Share on other sites More sharing options...
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