Looking to fine tune my 365 off grid system since 2015

offgridcabin2015 · December 2020

First hello Everyone. What a wonderful channel and support group.

I’m Neil and have been living in a small cabin 20x20 off grid since 2015.

I only now feel that I’m BEGINNING to learn.

A little about my system/ hardware.

I have 6 -6volt interstate Golf cart batts (232ah) + 2 – rolls Royce 6volt ( 235ah) Deep cycle. ( 5years old this feb 2021)

These are wired in 2 banks into a 24v configure inside my cabin .

I have a samlex 2000 pure syn inverter /has surge of 3500watts. / very reliable.

I have flexmax 80 / setup to 24volts.

I have a midnight pv6 combiner box. / all 15amp breakers.

I have a samlext 24-12 step down with my own copper bus bar I made out of a smashed flat copper pipe ( I tap and threaded holes) to accepted bolts to hold ALL neg’s / + Automotive bus bar (positive that holds the fuses) / 6 fuses in total. This is for all my 12v lighting and charing for 1 cell phone and tablet and lithum flashlight.

I have 5- 200 watts 24v panels (bought from internet , Ontario region) my 1st panels ever. ( 1000 watts) / wires in series 2 panels down to breaker / and 3 panels to breakers.

I have 4 – GMC 250 watt /Canadian made ( 1000watts) . wired in series to panels down to 2 separate breakers to combiner box.

I also have 2 – 300 watt GMC solar panels ground mount / leaning against cabin / wires in series. ( 600 watts)

I have another 2 – 300 watts not installed yet. (stored in garage)

Please note all panels are not south facing nor at the proper angle . the roof pitch is 2/12.

Thus very VERY poor rate of power coming into charge controller.

To give you some idea, Today over cast , rain at times/ thus zero sun.

I’m only bring in 3-6amps / then MPPT bumps it up to 6-14amps.

Normally the batts go into float mode almost daily. / depening on weather.

I treat my batts like babbies and only use lighly / 20-30 DOD. I will only turn on 46” led tv when the batts come to float.

I mostly use for 12 v lighting at night and recharge my phone / tablet and portable lithum speaker.

So I feel I have A LOT of room to finetune and get more results of BIGGER numbers . I feel like I should be able to live more comfortable.

Like STOP using propane and turn ac fridge on and run this off batts. Currently I cannot. I’m only bring in 1.2 kilowatts. And that’s’ on a Good day.

I need help in tracking numbers like what can i / should I expect to bring in volts.

I’m currently only bringing in 54 -79volts. HOnesly this seems super low. One breaker alone is rated for up to 150vdc. So can’t I expect to ramp up to over 90 -120volts? Or can I only expect this in cold temps and with snow reflecting and sun beaming on em? Am I being unrealistic?

Questions: if I use dc clamp metre around both neg/ pos pv wires for array on roof, what should I expect?i would read before it goes into combiner box?

Thanks peeps in advance, and hope to truly learn more and become an expert

With all the math involved.

Neil

wellbuilt · December 2020

So you have 2600 watts of panels @ 2on 12 roof bringing in 1.2 kw a day ?

For example I use a fm 80 with 5 strings of 3 295 watt panels , one string is 885 watts total @ 48v and brings in 700 / 750 watts per hour for 4 hours plus less power for the rest of the day my panels are on a 9 on 12 pitch roof facing south in NY so not a supper sunny area .

offgridcabin2015 · December 2020

hi, thanks for chiming in. so what your saying is. This is the NORM.? i'm not below in " bringing in power? Thanx in advance.
so 750x 4 is 3000. 3 kilo watts for you.

wellbuilt · December 2020

Nooooo if you are getting 1200watts 1.2 kw a day that sounds terrible to me
I get 2500 watts in 4 hours plus’s 6 or 700 more watts the rest of the day so 3000watts maybe 🤔
1000watt of solar should get you 700 watt per hour of sun on a nice day .

This time of year it is more like 350 / 400 watts because the sun is so low in the sky

wellbuilt · December 2020

Just thinking solar panels at 2 on 12 pitch really hurts production this time of year and having different arrays facing different direction plus running loads can really slow down the charging

New_Mexico_Will · December 2020

You say you baby your batteries but run them down to 20-30%? Do you mean that you are using 20-30%, or using 70-80%?

offgridcabin2015 · December 2020

for clarity to " new mexico will. i only use 20-30% of batts. thus baby em. I dont even run loads. I use a light at night that's it. ( 40watts) for maybe 2 hrs an d only recharge my phone and android tablet. You would think what i have for solar would be over kill.

i'm looking for a way to test the system . i wish bill would chime in for i read his replies in posts and i can follow what's he's replying with.

Next question. it' evident that panels are not south faceing nor at correct pitch and flex max is over maxed at 2600watts ( i'm told that 24v im not have no more than 2000 watts of solar.

Based on bills numbers. see below i plugged in my own stats here:

· 0.10 rate of charge * 464 AH battery bank (my bank) + 15 amps load a guess) = 61.4 Amps from charge controller (minimum)

· 61.4amps * 29v charging * (1.298) = watt array min 2311.

but i'm not facing correctly nor at correct angle. so i feel i can add more panels? and just turn off breaker on bright days?

your thoughts ?

/ but i think i really can get away with it for not facing and not at correct angle . Which is why i can just hit the breaker and turn off the power if i need to on bright days. But at least i can haVe breakers / 15 amp on when raining and over cast days. Far better than running a gas generator.
I honestly would think i'm not the only one to think of this.?
comments?

BB. · December 2020

The other guys know their stuff too... I am on grid, but like to "do the math" to at least model the system first--Then there are fewer surprises down the road (and gives you some aiming points to understand how your system is performing vs possible "problems").

I will assume that you have been measuring specific gravity and monitoring Amp*hours and/or Watt*Hours and using around 30% of the bank capacity... Starting will loads would give you around 25% +/- of bank capacity usage every day (2 days of storage and 50% maximum planned discharge is a good operating point).

So, loads:

2x parallel strings of 232 AH GC batteries = ~464 AH of capacity @ 24 volts (mixing old and new batteries is not great--But assume all is working OK for now)
464 AH * 0.30 usage * 24 volt battery bank * 1/0.85 AC inverter eff = 3,275 Watts*Hours per day usage

I think I have understood your setup and how you are using it. ~3,300 WH per day is a good place to be... Assuming 1x full size energy efficient refrigerator, LED lights, some water pumping, computer, TV, etc. A very efficient home that is a "near normal" electrical existance (albeit with lots of conservation on your part).

Regarding the 24 to 12 volt step down converter... If you are happy with its 12 volt performance--That is great... A DC to DC could be replaced in the future by a small AC inverter (possibly in the 300 Watt range)--And you can run 120 VAC LED lighting, the TV, cell phone charger, laptop, etc...

A 2,000 Watt inverter is on the large size--A smaller inverter may waste less power (tare losses)... Depends on how much you use the inverter too (on only with TV, or what).

Anyway, two calculations for sizing the solar array... First based on battery bank capacity. And the second based on loads and hours per day of sun... I know you have got the equations--But I like to go through the process so I can follow your system sizing decisions.

Rate of charge--5% for part time, 10%-13% for full time off grid--Upwards of 20-25% for difficult conditions (such as winter in the far north).

464 AH * 29.0 volts charging * 1/0.77 panel+controller deratings * 0.05 rate of charge = 834 Watt minimum array
464 AH * 29.0 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 1,748 Watt array nominal
464 AH * 29.0 volts charging * 1/0.77 panel+controller deratings * 0.13 rate of charge = 2,272 Watt array "typical cost effective"
464 AH * 29.0 volts charging * 1/0.77 panel+controller deratings * 0.20 rate of charge = 3,495 Watt array maxing out
464 AH * 29.0 volts charging * 1/0.77 panel+controller deratings * 0.25 rate of charge = 4,369 Watt array really maxing out
80 Amps (FM80 max output) * 29 volts charging * 1/0.77 panel+controller derating = 3,013 Watt array to

Generally, your batteries will last longer if they are charged in the 10% to 13% rate of charge... You could program the FM80 to limit its output current less than 80 Amps:

80 Amps / 464 AH battery bank = 0.17 = 17% rate of charge -- probably not the worst thing to have a single FM80 at max output

Of course, you can "over panel" the FM80 to support more current during winter/poor sun conditions. Just keep the FM80 cool/well ventilated and use the remote battery temperature sensor (high charging current can overheat the battery bank).

And there is sizing the solar array based on hours of sun and seasons (and how much you want to use a genset).

How much sun... Fixed array facing south:
http://www.solarelectricityhandbook.com/solar-irradiance.html

Brampton
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 46° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
2.71	3.50	4.04	4.50	4.75	5.12
Jul	Aug	Sep	Oct	Nov	Dec
5.24	4.98	4.58	3.68	2.47	2.24

Lets say you want as little genset usage as possible... December average is 2.24 hours of sun per day.
3,275 WH per day * 1/0.52 off grid AC system eff * 1/2.24 hours of sun per day = 2,812 Watt array "break even" December

So that gives you a range of solar panels that would "make sense" for your system... There is the issue of breaking up base loads (that must always run, such as a refrigerator, water pump, lightning, cell phone) and optional loads (TV, washing machine, vacuuming, etc.). Your base loads should be about 50-65% of your "predicted loads"... Assume that you turn of the optional loads (or run the genset) during dark days/bad weather.

Now, looking at your solar array--I am not sure I understand what you are doing here... Your Vmp-std for the array should be at least 1.3x your battery bank charging voltage, and not exceed the 140-150 VDC Vpanel-max input of the FM80 (Voc-very-cold-array)... Normally that would be:

1.3 * 29 volts charging = 37.7 Volts Vmp-array minimum
Roughly Vmp-array = ~100 Volts max (this is really Voc-cold-array voltage under 140 VAC)

Need to know the Voc/Vmp/Imp of your panels--And your coldest weather (Voc rises in very cold weather).

For example, you have 5 solar panels--2 in series * 2 parallel strings and 1 single panel??? To the combiner box? And you have more panels too...

This is going to get a bit complicated... When you connect panels in series, you should match Imp within 10% (i.e., both panels 10 amps, or one panel 10 amps and the second panel 9 amps Imp).

When connecting panels (or strings of panels), they should match Vmp to within 10%...

The vmp-array--You have a "good operating range" of ~37.7 volts to ~100 volts...

You talked about "24 volt panels"... Those could be Vmp~30 volt panels (60 cell panels), or they could be Vmp=36 volts (72 cell panels).

You cannot really easily mix 30 and 36 volt panels together on one MPPT controller (too wide of Vmp-string range... >10% difference).

If you have 30 volt Vmp panels, 2x series is Vmp-array=60 volts (very good). And 3x series = Vmp-array=90 volts (also good)

If you have 36 volt Vmp panels, 2x series would be 72 volts Vmp.. 3x in series give you 108 volt Vmp--But could give you >140 VDC for Voc-cold and damage the FM80 from over voltage during cold snaps. Need to check the details here.

Now, you can put all panels on a single "plane" pointing south--Most harvest... But lead acid batteries "like" longer charging times--And your short days in winter is not great for time on charge. An option is to do "virtual" tracking... For example put 1/2 the array facing south east, and the other 1/2 facing south west. That way you "stretch out the charging/harvest" from your array. You usually do not lose to much harvest from not pointing south.

I will stop here for the moment... Focus on your array design and how it will point... If you have lots of snow--Tilting the array(s) more vertical will give help you shed snow better (as I understand--I live in sunny California and only see ice in my freezer).

Once we get the sorted, we can have further discussions on inverters, generators, AC charging, and other issues.

Hope this helps...

-Bill

Photowhit · December 2020

offgridcabin2015 said:

First hello Everyone. What a wonderful channel and support group.

I’m Neil and have been living in a small cabin 20x20 off grid since 2015.
//
With all the math involved.

Welcome! Does seem we do a lot of math around here...lol.

offgridcabin2015 said:

I have 6 -6volt interstate Golf cart batts (232ah) + 2 – rolls Royce 6volt ( 235ah) Deep cycle. ( 5years old this feb 2021)

These are wired in 2 banks into a 24v configure inside my cabin .

As Bill said, and I concure, it's NOT a good idea of mixing new with old batteries. Typially it will prematurely age the new batteries bring their capacity down to the old batteries.

If inside your cabin, you should make provisions to vent to the outside, particularly in a small space.

offgridcabin2015 said:

I have a samlex 2000 pure syn inverter /has surge of 3500watts. / very reliable.

I have flexmax 80 / setup to 24volts.

I have a midnight pv6 combiner box. / all 15amp breakers.

I have a samlext 24-12 step down with my own copper bus bar I made out of a smashed flat copper pipe ( I tap and threaded holes) to accepted bolts to hold ALL neg’s / + Automotive bus bar (positive that holds the fuses) / 6 fuses in total. This is for all my 12v lighting and charing for 1 cell phone and tablet and lithum flashlight.

This is all pretty good equipment and setup. I hope you read the instructions to properly setup your inverter with correct gauge wire from your battery bank.

offgridcabin2015 said:

I have 5- 200 watts 24v panels (bought from internet , Ontario region) my 1st panels ever. ( 1000 watts) / wires in series 2 panels down to breaker / and 3 panels to breakers.

I have 4 – GMC 250 watt /Canadian made ( 1000watts) . wired in series to panels down to 2 separate breakers to combiner box.

I also have 2 – 300 watt GMC solar panels ground mount / leaning against cabin / wires in series. ( 600 watts)

I have another 2 – 300 watts not installed yet. (stored in garage)

This can get very ugly. If you would like help, I'd suggest letting us know the VMP and rated output of each panel.
MPPT type charge controller like to see even distribution of voltages for best performance.

Having 5 like panels wired in 2 strings in parallel, 1 string with 2 panels and one with 3 panels likely won't be any different than having 2 strings with 2 panels in parallel.

Having 4 250 watt panels wired in series also in parallel, could likely damage your charge controller as it would exceed the maximum VOC for the controller. (Oddly having all them wired in parallel might have saved you!)

So do you have direct exposure to the southern sky? Do you have much shading during the day? Would you like to setup the panels to make best use of the panels and are you willing to do a ground mount?

Bill posted the average exposure for optimally setup panels, but for panels at 17 degrees facing south (if your roof faces directly south) your average for this time of year is more like 1.7 hours a day...

You can plug in your numbers at https://pvwatts.nrel.gov/

offgridcabin2015 said:

Please note all panels are not south facing nor at the proper angle . the roof pitch is 2/12.

Thus very VERY poor rate of power coming into charge controller.

To give you some idea, Today over cast , rain at times/ thus zero sun.

I’m only bring in 3-6amps / then MPPT bumps it up to 6-14amps.

///////////////////////////

I’m currently only bringing in 54 -79volts. HOnesly this seems super low. One breaker alone is rated for up to 150vdc. So can’t I expect to ramp up to over 90 -120volts? Or can I only expect this in cold temps and with snow reflecting and sun beaming on em? Am I being unrealistic?

Clouds/shade will take away most of any production from a solar panel/array. On Cloudy days with no disctinct shade, I don't expect more than 10% of the arrays typical output. (Typical output will be about 75% of the rated output in panels that are close to perpendicular to the sun, you have already said yours are not)

In coming voltage will depend on the panels VMP. Typically it will be about 90% of the VMP. Usually a panel will produce most of it's VMP without regard to the angle to the sun. The more directly the panel is facing the sun the more current (amperage) the panel will produce. Panels in the same string should be in the same plane to the sun.

Breakers are just choke points and have nothing to do with how much voltage is produced.

I did not find any GMC 250 watt solar panels, but did find some GMC 250 watt panels, here are their specs;

When solar panels are strung together + to - their voltages add and the current remains the same. Voltage 'x' Amperage(current) = Wattage (a unit of power)

So a string of 4 of these panels has a rated VMP of 4x30.5vlts(VMP) or 122 volts and a VOC (voltage open circuit) of 4 x 37.6=150.4 volts. When very cold the VOC can exceed this, Your charge controller is rated to 150 volts. The reason for my concern.

What the MPPT type charge controller does is conserve power by converting the incoming power at (we'll pretend it is producing full power) of 122 volts at 8.2 amps (the IMP) or 122vx8.2a=1000.4 watts and it converters it with some minor losses to a voltage and current you can use say charging a 24 volt Flooded Lead Acid (FLA)battery bank at 29 volts and 34 amps.

With Flooded batteries once you reach about 80% full they start accepting less current. Typically they can accept 13-20% of their rated capacity below 80% and it tapers off from there. So if you are reaching float several times a week, what you might percieve as low charging might be that you are at absorb and the batteries are accepting less current.

Here's a brief description of battery charging;

During charging, there are basically 3 stages of charging, Bulk, Absorb, and Float.

BULK;

First thing when charging starts you will be in bulk, the voltage rises from what ever the system voltage was to a set point, around 14.5 volts in a 12 volt system or 29 volts in a 24 volt system. At that point the Charge controller stops the voltage from rising. Higher voltage can damage sealed batteries.

ABSORB;

Once the battery hits the preset point the charge controller keeps it at that point. Your batteries are roughly 80% full. Flooded batteries will start accepting less current at 80-85% full AGM/Sealed may go a little longer before accepting less current.

On many controllers you can set this point, Some will have different presets for Flooded, and sealed batteries, or flooded, AGM, and sealed batteries.

The charge controller has a couple ways to know when to switch to float, Most inexpensive Charge controller are just timed for 1.5-2 hours. Some will also see less current flowing through the charge controller and shut it down when minimal current is flowing through the controller. On more expensive charge controller. You can set battery capacity to give the Controller a better idea of when to stop. you can also set a longer Absorb time. Or set 'end amps' a amount of amps flowing through the charge controller to stop Absorb and switch to the final stage.

FLOAT;

Once the Controller has determined the battery is fully charged it reduces the voltage to a point where very little current is flowing to the battery. This will prevent the battery from over charging and heating up.

While in 'Float' the charge controller watch for voltage drop, which would indicate a load. If the voltage begins to drop the charge controller will allow as much current to flow from the panels/array to compensate and maintain the voltage. If the voltage can be maintained, the load will in essence be running directly off the array/solar. If the voltage drops below the preset float voltage, the controller may start a whole new cycle if it stays there for a period of time.

The system voltage drop you see at night when the sun goes down is the charge controller moving into a resting mode with no energy to contribute to the system.

The morning voltage may reflect a load present that is effecting the voltage level.

I would hope you could get most of the energy needed to run a fridge from your current system with proper orientation of your panels. Let us hear what panels you have and if you have direct exposure to the southern sky.

offgridcabin2015 · December 2020

Dec 08 2020 : reply to above:

Thankyou Bill for chiming in. (Certainly appreciate the well thoughout details) and to ALL those who help on this channel. THANKYOU!!

I’m really loving the learning as I live this solar and feel the need to understand it more and specially the math behind it (for I often struggle) and hop on utube for answers and for better understanding.

Fridge is propane and AC. I run it 100% propane.

UNIQUE 10 CU/FT Propane Fridge with Freezer - Stainless Steel

Operation: Propane (LPG) / AC (110V backup) / Model Number:

UGP-10C

NOTE: Recently it wouldn’t say lit so I hooked it up to the inverter and ran super quiet but I feel it ran down batts to 50% dod. And bad timing for it’s now dec and I’m trying to regain batts to FULL CHARGE. (almost happened today for sun came out for like 10 mins. Lol) batts began to sizzle. But never came out of bulk mode.

But with all this rain / snow, that hasn’t happened yet. Lol.

Luckily the fridge works now on 100% propane. Whew!!

I haul in water / old school . NO well. No pumps etc.

I’m only watch tv during the day only AFTER the batts go into float , which is often daily in june , july, aug sept , oct.. Now tho winter is here . Today only brought in 0.7kilowatts / I think I recall 21 ah put into batts the flex max showed. It’s now dark at 430/5pm ast. So flex max goes int Zzzzz mode.

I think this is directly related to poor angle and direction they face of panels.

Which honestly I’m okies with for now.

Question: if flexmax states max in pv array is 2000watts @ 24 volt. I feel they assume this is factoring in cold temps. So we get to -40 here rarely but -32 is common with wind.

Do you feel I could over panel the flexmax 80 to say 3000watts / so additional 1000watts on 2 -15amp breakers on my MNPV6 (Midnight pv combiner box). My goal is to have more power in winter only when im home and when I leave for work I can keep both breakers off ( 1000watts) in 2 + 2 panels in series to combiner box.

I will give you details on solar panels. See below:

Array # 1 is 200watts / 24v panels / (uknown cell count) MADE by Sunbe solar : Vmp 37.2 , Imp 5.38 / Voc 45.00. (direct from the sticker on back of panels) seems odd tho since these numbers are higher than my 300 watts panels. / : wired in 2 + 3 series into 2 breakers into combiner box. / on ½ roof of 2/12 pitch facing east / no control here . this is the roof line.

Array #2 is 4 – 250watts GMC 24v / 60 cell / vmp 30.5 / Imp 8.2 / voc 37.6 /solar wired in 2 +2 series into 2 breakers into combiner box./ 15 amp breakers. / located on the other ½ roof pitch facing north.

Array # 3 is 2 – 300 watts24v / 60 cell / vmp 32.15 / imp 9.33 / voc 39.61 , isc 9.78 . Ground mount , simply leaning againt cabin , facing the most sun in winter. Wired in 2 series.

All panels are bought in groups so they are matched in there respective strings.

Samlex 2000watts (puresyn_wave)

This is only on when I want to watch my 46 led 3d tv. Honestly ONLY ON when the batts have come to float in summer mths. IT’S ALWAYS off when I leave cabin.

I love the mention of over paneling for I can achieve this really and yes I do have the flexmax temp connected to batts from day one.

QUESTION. SO batts are 232 ah ( interstate golf cart) , if I’m doing 10% of that, what would be 23 amps charge correct? Now I assume I never see this for when I look at charge controller I mostly see 9-14amp going into batts.

Is this something that flex max does on it’s own / automatically? Or do I need to program that somehow and if I do. How? (plz and thanks)

LOADS I have AT cabin :

Tv , smart phone / tablet . Dc ceiling fax (12v , 6 speed , reversible) and dc 40 watts led batt light.

OH and a car charger I use every now / again to charge a 12v car batt for my radio.

(separate 12v batt) dedicated to dc radio) just a junk batt given to me .

I forgot to mention I have a battery saver / (dc 12/24) I’m told it sends pulses so that it never builds up sulfate (who really knows) but I wanted to protect my long term investments.

Question. I want to test my voc at the breaker on my combiner box. Watched a few vids (alt E) I feel she’s really helpful and has been around forever.

So i turn one breaker off/ and read 60 this is on two 300 watt panels / series.

But

I also read 60 for all the other breakers / I feel the numbers should be higher? And when I read the combined out / the parallel finger bus bar , should n’t this be the total / the sum of all voc coming in from ALL strings? And yet when I look at mppt controller , only shows the same 60 or so. Thoughts.

Also ty for the chart on radiance : dec lowest month of year.I wanted to share that i have now understanding that as result of low sunlight and for such a tiny window for this month , this is why the batts have NOT come to float since 14 days ago. It's not a result of bad batts.

I did fast check when home on ALL 8 -6 VOLTS cells across the terminals when i got home , so they have been at rest for above 5 hrs.

cells all at 6.2 . Now if i had found a low number , then i have to pull out my fractometer to measure cell gravity. Really cool little device. Place droplet on slide and look into scope and voila tell me the number with temp . far better then those batt hydrometers.

offgridcabin2015 · December 2020

update:for the most part , batts are coming to full charge daily. (and i'm shovelling snow off panels twice daily) c'mon SPRING.

Photowhit · December 2020

I wrote this LOOONG ago, but got frustrated with our forum software, when I lost the curser in the bottom linked comment. The software had saved it. The info is good s I posted as is...

Don't shoot me, just some things that will help you understand how things work;

offgridcabin2015 said:
Fridge is propane and AC. I run it 100% propane.
UNIQUE 10 CU/FT Propane Fridge with Freezer - Stainless Steel

Operation: Propane (LPG) / AC (110V backup) / Model Number:

UGP-10C

NOTE: Recently it wouldn’t say lit so I hooked it up to the inverter and ran super quiet but I feel it ran down batts to 50% dod. And bad timing for it’s now dec and I’m trying to regain batts to FULL CHARGE. (almost happened today for sun came out for like 10 mins. Lol) batts began to sizzle. But never came out of bulk mode.

Propane fridges are run on propane, Some have AC backup. While technically, yes, it will run on AC or propane, it is quite a bit different than an AC fridge. What a propane fridge does when on AC power is it runs a AC heater in place of the propane heater to compress the gas. This has very poor efficiency compared to an AC fridge that runs on a Compressor. As you discovered when trying to run it on AC.

offgridcabin2015 said:
Question: if flexmax states max in pv array is 2000watts @ 24 volt. I feel they assume this is factoring in cold temps. So we get to -40 here rarely but -32 is common with wind.

Do you feel I could over panel the flexmax 80 to say 3000watts / so additional 1000watts on 2 -15amp breakers on my MNPV6 (Midnight pv combiner box). My goal is to have more power in winter only when im home and when I leave for work I can keep both breakers off ( 1000watts) in 2 + 2 panels in series to combiner box.

It looks like Outback has a hard maximum input limit of 2000 watts for a 24 volt system. I'd stick with that, though you may well be onto some truth, I would eliminate any possible problems until you system is functioning properly.

offgridcabin2015 said:
Samlex 2000watts (puresyn_wave)

This is only on when I want to watch my 46 led 3d tv. Honestly ONLY ON when the batts have come to float in summer mths. IT’S ALWAYS off when I leave cabin.

I love the mention of over paneling for I can achieve this really and yes I do have the flexmax temp connected to batts from day one.

offgridcabin2015 · December 2020

Thanks photowhit for your reply. ( dec 15 2020)
I have a question that i cannot solve on propane fridge. I have it vented thru wall and a dryer vent with plastic slots that cover it ( the idea is to keep the wind out ) but it's NOT.

When it' super windy , the wind finds it's way into the aluminum vent pipe and blows up the fire in the burn tube/ chamber and fridge is off.
I"m grown tired of this and happens every time windy. So how are others preventing this. Do we have a picture of the venting so i can copy that idea and not have the wind blown out the fire / in burn tube. Thanks Everyone, and be safe. Neil.

wellbuilt · December 2020

Well in my opinion ( im still learning here) the best thing you could do is get a solar bank facing south at a decent angle.

The sun is so low in the sky you are not making power .

My system is on a 9on 12 pitch on the top of a Mountain with good sun morning till dark.

If my panels where on a 2on 12 pitch I would not get much power .

I have a 48 volt system with 4500watts so a little over paneled , in June I can bring in 3700 watts at noon or a little more , in December I only see 2200 watts at noon on a perfect day , so I would say since your panels are allmost flat and pointing in a different direction then south you could add extra panels to your fm80 in the winter time any way .

Photowhit · December 2020

offgridcabin2015 said:

Thanks photowhit for your reply. ( dec 15 2020)
I have a question that i cannot solve on propane fridge. I have it vented thru wall and a dryer vent with plastic slots that cover it ( the idea is to keep the wind out ) but it's NOT.

When it' super windy , the wind finds it's way into the aluminum vent pipe and blows up the fire in the burn tube/ chamber and fridge is off.
I"m grown tired of this and happens every time windy. So how are others preventing this. Do we have a picture of the venting so i can copy that idea and not have the wind blown out the fire / in burn tube. Thanks Everyone, and be safe. Neil.

I have no clue, I wish I did!

I'm sure it has to do with vacuum/pressures created by the wind blowing over the surface. I have the same problems when it's super windy here in the winter, I can't dampen the wood stove enough and it can get pretty warm in the central room.

I understand Unique is a pretty good company, might ask them about a venting cap to keep pressures neutral.

mcgivor · December 2020

offgridcabin2015 said:

Thanks photowhit for your reply. ( dec 15 2020)
I have a question that i cannot solve on propane fridge. I have it vented thru wall and a dryer vent with plastic slots that cover it ( the idea is to keep the wind out ) but it's NOT.

When it' super windy , the wind finds it's way into the aluminum vent pipe and blows up the fire in the burn tube/ chamber and fridge is off.
I"m grown tired of this and happens every time windy. So how are others preventing this. Do we have a picture of the venting so i can copy that idea and not have the wind blown out the fire / in burn tube. Thanks Everyone, and be safe. Neil.

You could try building a baffle to limit the venturi effect, multiple chambers with overlapping changes in direction, much like an exhaust muffler, a fiberglass media could be incorporated to further enhance the performance but this may require positive displacement via a small fan.

Then again the easiest solution would be to use an electric refrigerator which needs no venting but requires more electrical energy, count on approximately 1-1.5 kWh per day in most cases

Looking to fine tune my 365 off grid system since 2015

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Looking to fine tune my 365 off grid system since 2015

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BramptonAverage Solar Insolation figures

Categories

Brampton
Average Solar Insolation figures