Bragging rights
Cariboocoot
Banned Posts: 17,615 ✭✭✭
I know a lot of people think I don't know what I'm talking about because I'm not wealthy. Obviously the key to knowledge to some people is having lots of money. Sorry; spent mine on an actual education. 
Anyway I checked my own system yesterday for the first time since last October. MX60 read 'Float', water levels were not down enough to bother refilling (this will increase when it gets to cycling more), and ALL cells were at 1.275 - fully charged.
No compromised less-than-100% charging, no reduction in settings for Winter, no need to run generator automatically. None of that crap you may have been fed by people whose systems work purely out of brute force, utter stupidity, and lots of cash.
In other words my own personal system is still working perfectly. I'm rather smug about that.
Anyway I checked my own system yesterday for the first time since last October. MX60 read 'Float', water levels were not down enough to bother refilling (this will increase when it gets to cycling more), and ALL cells were at 1.275 - fully charged.
No compromised less-than-100% charging, no reduction in settings for Winter, no need to run generator automatically. None of that crap you may have been fed by people whose systems work purely out of brute force, utter stupidity, and lots of cash.
In other words my own personal system is still working perfectly. I'm rather smug about that.
Comments
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Re: Bragging rights
Good to hear man
Where abouts in BC do you have your off grid cabin? -
Re: Bragging rightsGood to hear man
Where abouts in BC do you have your off grid cabin?
See if you can guess. -
Re: Bragging rights
For some reason, I picture you in the Shuswap Adams lake are? -
Re: Bragging rightsFor some reason, I picture you in the Shuswap Adams lake are?
Nah, further North and West: 100 Mile House area. -
Re: Bragging rights
Oh wow, your waaaaay north of us. Any sign of spring up there yet? -
Re: Bragging rights
Kudos for a well designed system and returning to finding it functioning as you expected it to. -
Re: Bragging rightsOh wow, your waaaaay north of us. Any sign of spring up there yet?
There's still snow piled in the dark corners but things are starting to green up.Blackcherry04 wrote:Kudos for a well designed system and returning to finding it functioning as you expected it to.
Thanks. I worry about over Winter because of the bad things that could happen - like tree limbs hitting panels. So far, so good. -
Re: Bragging rights
Good going......knowledge is always wealthier than a big pile of momey. -
Re: Bragging rights
People who know a lot, in my book, are people who get things done with well spent time, effort and resources, and they are never afraid to share their experiences and knowledge.
So well done Cariboocoot, you are really rich in my eyes !!! :-)
Ps. You may be heading for spring, we are heading for a rainy wet winter with maybe some snow on the mountains, in the next few months. :-)5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied. -
Re: Bragging rights
I have to say there is a reason people take your advise seriously. Your knowledge is pretty darn extensive on this subject for sure. I am sure it is not the only one you delve into as well.
Congraties on another winter overcome.:D:D Just goes to show you planning is everything.
As far as money goes, it is all about having enough. How do you know if it is enough? Just goes to show you planning is everything. -
Re: Bragging rights
Cariboocoot, are you still running the 700W PV setup in your signature? What all do you power with that?
I've been lurking for awhile as I design my off-grid system and it will be under 1KW as well so I'm curious. Thanks. -
Re: Bragging rightsCariboocoot, are you still running the 700W PV setup in your signature? What all do you power with that?
I've been lurking for awhile as I design my off-grid system and it will be under 1KW as well so I'm curious. Thanks.
Yes; 700 Watts is all. I have an advantage over some people in that the higher elevation here improves insolation, the daylight is quite long in Summer, and it is not used in Winter.
The system runs a full size (16 cu. ft.) refrigerator, satellite Internet set-up (including modem, router, phone adapter, and laptop - printer when required), lights as needed, water pumps (one in, one out - neither needs to run long), and occasional microwave zap. It sounds impossible but the total is only around 2.4 kW hours per day. Much of the efficiency is had by making use of daylight power that would otherwise go unrealized. This requires active load management (e.g. turn on the water pump to fill the tank when the batteries are up, same with the septic pump).
Mostly the batteries just keep a few things running over night, requiring only 50 Amp hours or so. Propane runs the stove and hot water. If the weather turns nasty the little Honda can bulk up the batteries on a minimal amount of fuel. -
Re: Bragging rights
Is your battery bank 24V and what are you using for a charger with the Honda generator? I have 3x 275W solarworld panels for 825W because I was able to get them shipped for only $25 USD. I will be running a freezer instead of a fridge with no microwave but our devices sound the same otherwise. -
Re: Bragging rightsIs your battery bank 24V and what are you using for a charger with the Honda generator? I have 3x 275W solarworld panels for 825W because I was able to get them shipped for only $25 USD. I will be running a freezer instead of a fridge with no microwave but our devices sound the same otherwise.
Battery bank is 24 Volt. The Outback VFX3524 has a built-in AC powered charger. Most of the time the gen isn't used: the panels an MX60 do the job.
I should explain here the difference in power at this elevation. Ordinary we expect a 77% derating so it would be 700 * 0.77 /24 = 22 Amps peak current. I get 82% or 700 * 0.82 /24 = 23 Amps peak current. Small, but significant. Exactly right for the 232 Amp hour PS2200 batteries. -
Re: Bragging rights
Yeah coot, I am in the southern midwest USA where insolation is 5 to 6 from March to September. December is the lowest month at 3.29. I should be ok.
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Re: Bragging rightsCariboocoot wrote: »Ordinary we expect a 77% derating so it would be 700 * 0.77 /24 = 22 Amps peak current. I get 82% or 700 * 0.82 /24 = 23 Amps peak current. Small, but significant. Exactly right for the 232 Amp hour PS2200 batteries.
So the 0.77 in your calcs comes from de-rating due to one location?Most areas in South Africa average more than 2 500 hours of sunshine per year, and average solar-radiation levels range between 4.5 and 6.5kWh/m2 in one day.
The southern African region, and in fact the whole of Africa, has sunshine all year round. The annual 24-hour global solar radiation average is about 220 W/m2 for South Africa, compared with about 150 W/m2 for parts of the USA, and about 100 W/m2 for Europe and the United Kingdom. This makes South Africa's local resource one of the highest in the world.
What would it be for SA, also 0.77?5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied. -
Re: Bragging rights
The 0.77 derating is "global" (really sea level with reasonably clear skies) for "average" best case power production.
0.81 derating * STC (standard test conditions), aka "marketing numbers for solar panels.
0.95 derating for solar charge controller (MPPT is the ~95% efficient)
0.81 panel * 0.95 MPPT controller derate = 0.77 panel+controller derating
For various reasons, the 0.77 derating is almost the same between PWM and MPPT controllers.
You can get better than 0.81 for higher climates and very cold (typically sub freezing) solar panels/weather with MPPT charge controllers... I think Marc has seen 0.83 derating for his system due to altitude and cool weather.
For battery losses (charging/discharging), flooded cell batteries are typically 0.80 to 0.90 efficient, depending on age, condition, how the owner charges them, average state of charge, etc.
AGM batteries can be 0.90 to 0.98 efficient...
But to be "conservative", I use 0.80 derating most of the time. Will work for new/old batteries, and those batteries that have less than ideal charging/power usage conditions.
And lastly, the AC inverter conversion... Around 0.85 work most of the time. Very lightly loaded inverters (2kW sine wave inverter with 10 watt load, or simply "on" waiting for loads) can have terrible efficiency. And inverters running near 100% load frequently are less than 0.85 efficient.
0.77 panel+controller * 0.80 flooded cell battery * 0.85 inverter eff = 0.52 end to end "efficiency" (based on panel STC rating).
There are other ratings (like PTC) which are based on actual panel/cell temperature under full sun--But most people just use the STC marketing numbers for calculations.
In the end, you are going to be lucky to get "theoretical to real life" numbers that agree within 10%... Many charge controllers seem to be ~5% or so "optimistic" on their production numbers. And you are not going to get much better than 3-5% accurate readings with most metering setups (battery monitors, Kill-a-Watt meters, etc.).
Add that you can have ~5-10% or year to year variations due to weather/local conditions--Being more accurate is just not worth the extra time/energy to do the calculations. Build your system 25% to 33% (or more) than your planned loads allows for streaks of bad weather and some head room as your power needs grow.
-BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset -
Re: Bragging rightsCariboocoot wrote: »Battery bank is 24 Volt. The Outback VFX3524 has a built-in AC powered charger. Most of the time the gen isn't used: the panels an MX60 do the job.
I should explain here the difference in power at this elevation. Ordinary we expect a 77% derating so it would be 700 * 0.77 /24 = 22 Amps peak current. I get 82% or 700 * 0.82 /24 = 23 Amps peak current. Small, but significant. Exactly right for the 232 Amp hour PS2200 batteries.
I found a table (Table 3 in this article) that displays the effects of elevation on insolation at a given latitude (in the case of the linked table, latitude 38.95N). If I'm reading it correctly, then insolation at an elevation of 1000 meters should be close to (insolation at sea level)/.89 . Doing the calculation doesn't quite give the results in the table, which leads me to believe that there's some rounding-induced errors, but it does come close (dividing global insolation at sea level [556.1 watts/m^2] by .89 = 624.8 watts/m^2, while the table gives global insolation at 1000 meters as 614.9 watts/m^2).
Is this the basic process by which you calculated your derating factor? -
Re: Bragging rightsIs this the basic process by which you calculated your derating factor?
Not exactly: I measured the output of the charge controller at full power. So where we would typically expect 77% I see 82% normally and yes Bill is correct I have had a high of 84%. -
Re: Bragging rights
Coot...good for you...sounds like you have a solid system and its working well.
I have this theory about people and mechanical/electrical things.....some people just have an instinct to do things right and the machines respond.....and some people can do no right. It's just the way the world works.23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring -
Re: Bragging rights
you're right coot as you do know what you're doing and have a right to pat yourself on the back in spite of somebody that said you don't know a *$%# thing last september. -
Re: Bragging rightsSouth Africa wrote: »So the 0.77 in your calcs comes from de-rating due to one location?
What would it be for SA, also 0.77?
You can use this calculator to determine expected energy from PV in SA: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php?map=africa it's pretty accurate for Europe. -
Re: Bragging rights
Thank you Stephen. This is a very nice tool.5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied. -
Re: Bragging rightsCariboocoot wrote: »The system runs a full size (16 cu. ft.) refrigerator, satellite Internet set-up (including modem, router, phone adapter, and laptop - printer when required), lights as needed, water pumps (one in, one out - neither needs to run long), and occasional microwave zap.
There goes the theory that you need a 3 Kilowatt array to run a ref.
Was your refrigerator powered during the entire time you were away?Paul -
Re: Bragging rightsThere goes the theory that you need a 3 Kilowatt array to run a ref.
Was your refrigerator powered during the entire time you were away?
Good heavens no! Over the Winter the inverter is shut down. Only the charge controller and array are left connected.
Our sunlight hours drop to 6 here in the snow season. What with the clouds and all (including mountains blocking a lot of light as the sun angle is quite low) you'd need a huge array and battery bank to keep going year 'round. Even then you could expect a significant increase in gen time.
No, come the Winter it's the ten cent electric from BC Hydro in the town house. Oh and before anyone thinks that having two houses makes me rich; the economy here is almost dead and houses can be had for a song. If this place of ours were in the Vancouver area it would have been four times the money. We bought the cabin 28 years ago when the government was cash grabbing and selling off leased land for a song.
When you haven't got much money you have to spend it well. -
Re: Bragging rights
Just will say too you. Well Done!!!
In lifestyle and the knowledge that you share.GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!! -
Re: Bragging rightsThere goes the theory that you need a 3 Kilowatt array to run a ref.
Was your refrigerator powered during the entire time you were away?
One has to look at Coots whole system from PV to batteries to inverter... it is the WHOLE package that makes it work the way it does for what he wants out of it. Not too much not too little....
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada -
Re: Bragging rights
Given your location and the extended sun in the summer, would you benefit from an active tracker?Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html -
Re: Bragging rightsGiven your location and the extended sun in the summer, would you benefit from an active tracker?
For the cost of such a device I could install more fixed panels and forgo the prospect of mechanical problems. The net power result would be the same: more Watt hours spread through the day. -
Re: Bragging rights
Or use a virtual array with each part set at a different orientation to the sun.
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
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