Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Help DIY solar generator
#31
later mike added a gfci, and a CB in this video
https://www.youtube.com/watch?v=260BClBogiY
later floyd
Reply
#32
(10-14-2020, 05:25 PM)swampf0x Wrote: In this video, there is not a fuse or breaker between the inverter and the outlets. Shouldn't there be? Or does the all in one take care of it?  https://youtu.be/XFn1j1mq1U8
He got comments on this and not only added a CB but also GFCI in the next youtube - https://youtu.be/260BClBogiY

Some inverters (such as AIMS pure sine wave) come with CB and GFCI built-in - so in that case it wouldn't be needed.     Some Charge controllers (such as Midnite Classics) have GFCI built-in as well.    These features can be found on more expensive equipment - but yes, they should be considered and if not provided by the equipment you can buy/wire them in yourself Smile.
Reply
#33
Thanks for the updated video. That confirmed my thoughts. However, in the video he says he's going to install a CB and GFCI but it only shows him installing a GFCI between the inverter and the receptacles. Did I miss something? I watched it like 4 times.

I was looking at Tesla's Power wall and their calculator. It says in my location with a $50 a month bill. (That's just a rough estimate of what I hope to save with this system). Anyways $50 a month with 2.5kw of solar will only give me 2.5 days of juice according to Tesla using their power wall. I believe their power wall is 10 Kwh isn't it? Does this sound about right for what I want to do with my home built system? I was hoping to have something that would run longer. I don't mind running the generator a little bit once in a while or a few minutes a day, just not half a day to a day every 3 days. I realize the batteries will drain faster on cloudy days and winter months.

Is my design too small for off grid applications? Fridge and freezer are priorities and probably use the most watts. The rest is just small items that don't use much electricity....... modem, router, Raspberry Pi PC, 50" LED TV, ceiling fan, 4 LED light bulbs, alarm clock, phone charging, Netflix/BluRay player. That's pretty much it.

With the All in one Inverter that I have picked out, 10 solar panels are all that it can stand. I could double the battery size to 15-20 Kwh, though I certainly hope that isn't necessary. Or should I get a bigger inverter and more solar panels?.....they would have to be located elsewhere as I don't have enough room where I plan to put my other panels

Thanks again guys and if I should move this thread elsewhere please instruct me where it belongs. I've strayed way off topic.

swampf0x
Reply
#34
The 20A GFCI breaker he installed is both a GFCI and a CB.
Reply
#35
OK I gottcha
Reply
#36
(10-19-2020, 04:16 PM)swampf0x Wrote: Is my design too small for off grid applications? Fridge and freezer are priorities and probably use the most watts. The rest is just small items that don't use much electricity....... modem, router, Raspberry Pi PC, 50" LED TV, ceiling fan, 4 LED light bulbs, alarm clock, phone charging, Netflix/BluRay player. That's pretty much it.
You say 2.5kw PV array.   I'm in Southern OR with what I would call a mild climate - pretty good sun.    My array is 12.85kw.   By extrapolation (2.5/12.85 = 19.5%) from my own numbers you could expect a max of 370kwh in July...  which is 12kw/day.    This is actual consumable power after subtracting inverter losses etc.

Fridge+Freezer is maybe 400w * 12hr (on 1/2 the day) = 4.8kwh/day.
Computer/TV stuff is maybe 300w * 24 = 7.2kwh/day.
Other Misc ...   let's just throw in 3kwh/day.

That's on the order of (4.8+7.2+3) 15kwh/day.   So even in the peak month of July to run 24/7 you will be at the max you have available  Winter is 25% of this.  Not sure of your expectations.   You are 'in the ballpark' but surely don't have enough run things you list 24/7 all year round Smile


(10-19-2020, 04:16 PM)swampf0x Wrote: With the All in one Inverter that I have picked out, 10 solar panels are all that it can stand. I could double the battery size to 15-20 Kwh, though I certainly hope that isn't necessary. Or should I get a bigger inverter and more solar panels?.....they would have to be located elsewhere as I don't have enough room where I plan to put my other panels
I have a 81kwh battery bank paired with the 12.85kw PV array.  I can consume all I produce with an average 40% DOD.   Again, by extrapolation you need a 15.8kwh battery bank for 40% DOD or at 80% DOD you only need a 8kwh battery bank to be able to consume all the 2.5kw PV power you create - so at 8kwh battery bank, that should not be the blocking issue.    

Doubling your battery bank won't get you more power - but only a lower DOD / longer life.  Incoming power is a direct function of the size of the PV array / weather.  I have 45 panels and wish I could fit at least 90 for winter - e.g. more panels are better Smile
Reply
#37
Will my system run just the fridge and freezer year around? Can I get by with any less? I know the fridge and freezer don't have to be ran as much as they run themselves so I can install timers and probably get by with 8 hours a day run time.

As expensive as this stuff is, it's almost like prepaying your electric company for a lifetime of service. I'd like to have some luxuries like TV and PC but I'll settle for the bare necessities for now and maybe build another system for the tv and stuff later on.

thanks,
swampf0x
Reply
#38
(10-20-2020, 03:00 PM)swampf0x Wrote: Will my system run just the fridge and freezer year around? Can I get by with any less? I know the fridge and freezer don't have to be ran as much as they run themselves so I can install timers and probably get by with 8 hours a day run time.
Beyond the general guidelines I gave in the last post - you'll have to figure this out for your specific situation.    Start with a killawatt meter (such as this - https://www.amazon.com/P3-P4400-Electric...B00009MDBU ) on your fridge and freezer and other stuff to get actual power requirements.   

You can use pvwatts ( https://pvwatts.nrel.gov/pvwatts.php ) with perhaps a 15% 'loss' number to get a pretty good estimate of the power you'll get in your location for each month.

Then - make plans.   Winter 3 months of PV power is about 25% of spring for me.    Also, things happen like I had 10days of heavy smoke from wildfires this summer - cut my power by 50%...   not to mention a few thunderstorms/heavy-clouds now an then cutting power by 50%.    

Its just not very practical to build (for DIY/home use) a week (or 2) battery bank....  unless your power needs are very very small.   To run a week, I would need a 400-600kwh battery bank...  talk about a fire hazard Smile

Your choices are wind, water, generator (gas/propane), additional panels, consume-less-power for the low periods - and of course combinations of all of these.    Wood gasifier generators and things like that just are not commercial quality to be real enough for me personally.      

In my case, if grid was lost for weeks, my vision is o temporarily deploy extra panels (instead of a generator) in the yard AND cut-back on usage A LOT.   That's the best I can do - but you're situation is of course unique to you.
Reply
#39
(10-20-2020, 03:00 PM)swampf0x Wrote: Will my system run just the fridge and freezer year around? Can I get by with any less? I know the fridge and freezer don't have to be ran as much as they run themselves so I can install timers and probably get by with 8 hours a day run time.

As expensive as this stuff is, it's almost like prepaying your electric company for a lifetime of service. I'd like to have some luxuries like TV and PC but I'll settle for the bare necessities for now and maybe build another system for the tv and stuff later on.

thanks,
swampf0x

Depends on your fridge/freezer and inverter. If you have an old fridge like mine, which is about 10+ years old (and a cheap one to boot!), they would have a hard start compressor. It just barely starts with my 2.4kw PIP. Once running it's fine, takes about 100-150watts or so. In a day it takes about 1-2kwh to run my fridge.

Same issue with window a/c units. They are cheap and have hard start compressors. So as long as your inverter is good enough then this wouldn't be a problem. Or if they're based on an inverter compressor (basically the compressor is a variable drive so it's a slow ramp up) then you're fine.
Reply
#40
My fridge is a watt sucking hog. Uses 6.5 Amps and is 22 years old. Haven't checked my freezer yet. It will be harder to check until I get a watt meter ....... for Christmas Sad

Anyways, this project is on hold. Looks like I need more wattage solar panels like the 400watt ones and a new high efficiency fridge.
4Kw of PV and 10 Kwh battery...................... I certainly hope will do it. Like I said, I can run the generator every now and then. It'll be fired up every week or so anyways. Might as well use that juice.

swampf0x
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)