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How much grid tie inverter capacity ?
#1
Here's a question with many answers... interesed in hearing views

For a grid tie install (with limiter capability) how much capaicty should you install for :
House with 5000kWh annual consumption
8kW peak load
230W base (24x7 server, standby, phones, fridge, etc.)
8kWp solar (7kW cloud edge, 6kW max charge rate capable)

Nearly forgot, northern climate, so big summer / winter difference.

Battery capacity is x kWh
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#2
If your house consumes 5000kwh/year, then 5000/365 = 13.7kwh/day. This implies a peak of 8kw is short lived - so you need equipment that can handle 8kw peaks (maybe 3x motor startup etc) so somthiing like a 10,000watt capable inverter with surge.

Direct stats from my working system:
Overall, yearly consumption: My 7kwh PV array in Southern Oregon is producing 9500kwh/year. By extrapolation that would be 3.64kw array for 5,000kwh/year. So say 4kw PV array as ballpark.

My 7kwh PV array produces 37kwh/day (useable power from inverter) in summer (Jun,Jul,Aug) and 9kwh/day in winter(Nov,Dec,Jan,Feb) and 1/2 way in between in the other months.

My home consumption averages 2,000w/hr 24/7 with peaks up to 6,000w for shorter periods.

My battery bank has been required to provide an average of 15kwh/day with peak of 18kwh/day so far to ensure 100% consumption of PV array input. Currently have a 40kwh battery bank and able to keep <40% DOD under these conditions.

Recap by extrapolation, you will need:
1) 4kw PV array (or larger)
2) 10,000watt inverter capability
3) 23kwh battery bank for 50% DOD range.
completelycharged likes this post
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#3
8KW are a very short time i think. So a Inverter with 2KW is enought.
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#4
Size on battery and PV totally depends on
1. Where you live
2. direction of the solar panels
3. Angle of the solar panels
4. how much load you use during day compare to night


And many more factors so our guesses is most likely based on either
1. Guesses
2. Our own setup

Smile

A grid tie system where I live with decent position would for 5000kWh yearly consumption need around 6kWp of solar panels to even it out during a whole year.
Over production during summer and under during winter. No way you can have a battery bank to cope with 365 days off grid here without changing how you use electricity due to winter perhaps yields 5-10% of the output compare to summer.

In my case 100kwh during summer days and 10kwh during winter at most.. I have had days with as little as 2kwh... thats 2%.
completelycharged likes this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#5
daromer, 2kWh winter output is at least above zero, so guessing your panels never end up fully covered in snow. Impressive solar output variation for the year. I get zero if I dont clear the snow off before it get's too deep..


nettermann90, I would tend to agree with this, why try to chase the last W if your grid tied as the last W ends up being very expensive to cover.

offgridinthecity, like the breakdown, very high consumption (compared to a typical UK house).... would you invest in more solar or more battery given your net winter imports or is the excess in summer stranded (no export payment) ?
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#6
2kwh is during days they arent covered. I dont count the days we have snow on them but with that said its every 10 years we have that much snow that it lasts more than 1 week anyways Tongue
completelycharged likes this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#7
(08-22-2019, 05:47 PM)completelycharged Wrote: offgridinthecity, like the breakdown, very high consumption (compared to a typical UK house).... would you invest in more solar or more battery given your net winter imports or is the excess in summer stranded (no export payment) ?
High consumption is due to a set computer servers I run 24/7 that burn 1200w/hr of that 2000w/hr.    In an emergency I would shut them off and just go with office computers.  

I'm process of expanding my PV array from 7kw array to 13kw to boost winter from 9kwh/day (average) to 17kwh/day for those 4 winter months.   However, this will have the natural consequence of boosting summer from 39 to 65'ish.    SO, I'm expanding my battery from 40kwh to 66kwh and adding a 2nd inverter capable of running a whole house heat pump.   I may have enough power during the 8 months of spring/summer/fall to approach heat/cool'ing of the whole house - but certainly enough to heat/cool subsets.
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31 User(s) read this thread:
daromer (08-22-2019, 08:26 PM), sl1me (08-28-2019, 03:49 AM), Wolf (08-22-2019, 08:38 PM), Generic (08-28-2019, 12:49 AM), Solardad (08-24-2019, 04:15 PM), ajw22 (08-22-2019, 10:28 AM), RikH (09-02-2019, 06:12 PM), OffGridInTheCity (08-22-2019, 08:14 PM), Richard (08-24-2019, 04:26 AM), Doin it (08-24-2019, 01:09 AM), sunbuzz (09-04-2019, 12:07 PM), Wulffi (08-21-2019, 06:33 PM), rcuetara (08-22-2019, 07:01 PM), nettermann90 (08-22-2019, 05:12 PM), emuland-metroman (08-22-2019, 07:16 PM), w0067814 (08-24-2019, 08:40 PM), Riplash (08-21-2019, 10:54 PM), Sean (08-22-2019, 08:26 PM), Korishan (08-21-2019, 08:22 PM), PAF (08-22-2019, 05:37 AM), jdeadman (08-23-2019, 12:58 AM), wim (08-22-2019, 06:03 AM), jesusangel (08-23-2019, 07:10 AM), Geek (08-23-2019, 02:57 AM), slimf (09-05-2019, 10:23 AM), Oz18650 (08-22-2019, 04:55 AM), Crimp Daddy (08-22-2019, 05:30 PM), completelycharged (08-23-2019, 04:46 PM), avm131 (08-24-2019, 03:42 PM), Bubba (08-23-2019, 12:53 AM), icho (08-31-2019, 10:26 AM)

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