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I found out now it...
 
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I found out now it takes a lot of battery to go off-grid at night .

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(@dickson)
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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 .    


   
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dochubert
(@dochubert)
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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.


   
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(@dickson)
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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 .   


   
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(@thebutcher)
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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.


   
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(@dickson)
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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  ?   


   
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(@thebutcher)
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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.


   
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(@dickson)
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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 .     


   
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(@thebutcher)
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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.


   
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(@dickson)
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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   .   


   
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(@thebutcher)
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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. 🙂


   
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(@dickson)
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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

I  know  I    can't both charge and discharge a battery.  It's one or the other .    Sean  say on  youtube all the time he can  not  do that .   That is why he only  can run the GS 12 kw one hour at   night  on battery  and have to use the grid at night  with NO   generator  to charge the battery .       Sorry my   logic / thought paths are about as broken as  PJ  advertising   🙂        The reason   the above response doesn't work is if what I   stated is not what I   are actually doing .     I   am sure  some  PJ  user  will connect the grid to the  input  to try to charge the battery  and  also  connect the  output to the grid  .      I  thought about  doing that  many  in this forum  but  Sid  say my  PJ  will  blow up so I   have not try  .   I  thought  the rev 11.3 control board is so  good that  a  PJ  inverter is protected  no matter what  a  stupid  user do to it   .    


   
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(@dickson)
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The person that did say it was inPhase.  Probably best that you don't attribute one person's post to another. 🙂

Sorry  .                     

Posted 6 hours ago

That 18 kW Sigineer has an EI transformer and idles at 250 watts     by  inPhase  .      


   
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(@thebutcher)
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Sorry mate I simply can't make head nor tail of what you are saying.  It's like herding cats, something best not attempted so I'll stop annoying you.


   
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(@inphase)
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I got the 250 watt figure from the Sigineer documentation.


   
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dochubert
(@dochubert)
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Posted by: @thebutcher
You can't both charge and discharge a battery.

That one has me scratching my head also. 

I have a lot of solar to allow me to run the house and keep the batteries full during the day.  This allows me to have a full charge at sunset for running the house all night.  We don't use much power overnight.  10 amps or less (usually less) average draw to the powerjack overnight.  10a doesn't impact my battery bank significantly, so the voltage drop overnight is acceptable during short summer nights.

My battery bank is at least twice the capacity I probably 'need'.  My solar can and does produce 120 to 150 amps of charging to that bank as needed on a good summer day.  Also, some of my panels face east, some west and some south.  Charging starts as soon as the sun is above the horizon and continues at significant levels until sunset.  Because they listen to "Solar Power Experts", most people only have south facing panels, which don't produce significant output until much later in the day than my east facing panels.  And those south facing panels drop off their charging as the sun angles towards sunset.  My west facing panels pick up their charging in the afternoon till sunset.  So I get a much longer 'charging day' with this setup than those with south-only panels.

Also, with more solar than I 'need' for a summer day means I can run on a partly cloudy or even mostly cloudy day and still get an adequate charge, so I don't do more than keep an eye on things.  We've been having many cloudy days recently and I've cruised right through them all with no problems.  Yesterday was almost nothing but rain and clouds and I still made it through the day with a fairly full charge, so I'm happy with my system as it stands currently.

Dickson, hope you get things figured out the way you want.


   
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