Adding solar to an old on grid homestead

[Bacpacker]

Have you considered setting up some or all your panels to track the sun (ie on some sort of rotating base)?

The power harvesting gain is typically about 40%.

Because my panels are used for camping or emergency backup, my tracking is the manual type (ie I move the panels every hour or two).

For temporary ground mounted or relocatable panels, tracking is a good option to have especially if you get a run of those less productive days.......

Great point. Another option, if you have multiple panels. Split them and face half more easterly, the other half more westerly. It'll give you more early and late than a set strictly facing due south.

 

[Hardcalibres]

Great point. Another option, if you have multiple panels. Split them and face half more easterly, the other half more westerly. It'll give you more early and late than a set strictly facing due south.

Yes - that can be a good option to avoid the "feast or famine" effect with solar controllers and LA batteries.

While the amp hour way of looking at power output and charging would say that 20A for five hours is the same as 10A for ten hours, it is not. The controller will start to cut back the current to the battery as the voltage in the system rises.

You are always going to achieve more charge from a medium amount of current for more hours each day than with a big current for fewer hours.

 

[viking]

Hardcalibres is right on, large current charging pushes the batteries too hard and they tend to gas off and evaporate electrolytes too quickly, leading to more frequent topping off the electrolytes. Probably shortens the life of the batteries as well. I am very thankful for the way our inverter/charger and MPPT solar controller are designed so they don't overcharge the battery banks, almost every time I check my system the charge level is at Float with just a few amps showing as the charge rate.

 

[Neb]

Great point. Another option, if you have multiple panels. Split them and face half more easterly, the other half more westerly. It'll give you more early and late than a set strictly facing due south.

I have watched a lot of Engineer775 videos where he installed solar panels...




I can not recall ever seeing him use a sun tracking system.

He makes a living installing prepper stuff so i question sun tracking.

Ben

 

[Bacpacker]

Sun tracking systems certainly work to boost the gain. But you consume some with auto tracking or have to do it manually thru the day.

I needbto subscribe to 775 and watch some vids

 

[Hardcalibres]

I have watched a lot of Engineer775 videos where he installed solar panels...




I can not recall ever seeing him use a sun tracking system.

He makes a living installing prepper stuff so i question sun tracking.

Ben

The more panels you have in your system, the more technically difficult tracking becomes........the vast majority of panels in the world are fixed on a roof (and it is difficult to rotate the house). Many of the panels that are not roof mounted, are on storm proofed ground frames that are also difficult to rotate........but some survivalists are among that small remaining minority.

There is also the idea out there that for permanently mounted panels, setting up tracking to gain say 40% output, costs more than just buying 40% more panels and accepting the inefficiency that comes from fixed azimuth panels.

But for people like:

1) me - who has all my panels configured for portable use and ground mount and;
2) people who are setting up a small backyard ground mount system, are limited on budget, have an ambitious target for panel performance and are a bit of a handyman

setting up some or all panels to track or setting up different panels on different azimuth is worth considering.

Like a lot of web/survivalism discussion subjects, to track or not track, is situational.

But it is:

1) just basic physics that a very substantial increase in performance is gained, if the panels are as perpendicular to the sun for as many hours of sunlight as possible - and that means having the panels at the optimum inclination to horizontal and facing towards the sun on the right azimuth
2) advantageous to produce the more uniform current output through the day that comes from a smaller number of tracking panels than a larger number of fixed panels

So for at least some people, tracking is worth considering.........

For me, with portable ground mount panels, to not track the sun during the day would be flat out lazy.

 

[Neb]

Sun tracking systems certainly work to boost the gain. But you consume some with auto tracking or have to do it manually thru the day.

I needbto subscribe to 775 and watch some vids

Yes!

The Princess and I have considered flying him in to to walk our property and consult what we can do with our dozen or so springs.

He has done so many instructive videos it is hard to name the most important but would suggest the developing a spring...



And his underground bunker



Note
The install videos may have been taken down.

The reason I have my water needs covered is because I was learned by him.

Sorry for the off topic...

Ben

 

[Neb]

The more panels you have in your system, the more technically difficult tracking becomes........the vast majority of panels in the world are fixed on a roof (and it is difficult to rotate the house). Many of the panels that are not roof mounted, are on storm proofed ground frames that are also difficult to rotate........but some survivalists are among that small remaining minority.

There is also the idea out there that for permanently mounted panels, setting up tracking to gain say 40% output costs more than just buying 40% more panels and accepting the inefficiency that comes from fixed azimuth panels.

But for people like:

1) me - who has all my panels configured for portable use and ground mount and;
2) people who are setting up a small backyard ground mount system, are limited on budget, have an ambitious target for panel performance and are a bit of a handyman

setting up some or all panels to track or setting up different panels on different azimuth is worth considering.

Like a lot of web/survivalism discussion subjects, to track or not track, is situational.

But it is:

1) just basic physics that a very substantial increase in performance is gained, if the panels are as perpendicular to the sun for as many hours of sunlight as possible - and that means having the panels at the optimum inclination to horizontal and facing towards the sun on the right azimuth
2) advantageous to produce the more uniform current output through the day that comes from a smaller number of tracking panels than a larger number of fixed panels

So for at least some people, tracking is worth considering.........

For me, with portable ground mount panels, to not track the sun during the day would be flat out lazy.

But would you be doing it manually or automating the tracking?

I was consulting in Spain soon after they invested in a mega watt solar collection system ...

https://en.m.wikipedia.org/wiki/PS20_solar_power_plant
And my host engineer ranted about the boondoggle and taught me a new word "foo-ked".

Ben

 

[Hardcalibres]

But would you be doing it manually or automating the tracking?

That depends upon the system......for my 50-300W portable ground panels, I move them manually.

For someone with handyman skills installing a homestead backup system (on a semi permanent mount) to run a freezer or some important medical gear, they could have their ground mount frame on a turntable or even powered with a reduction gear to match the path of the sun through the day.

As I posted, that 40% gain in performance could make the difference between fully recharging the batteries, even on the cloudy days or not. For someone on a budget or someone trying to hide their solar system, setting up tracking may be a better option than just buying more panels. It may also be worth setting up different panels pointing in different directions to smooth out current delivery.....

But for a system running a whole homestead offgrid 24/7, tracking is unlikely to be a good option.

I was consulting in Spain soon after they invested in a mega watt solar collection system ...

On a big industrial sized solar power system, tracking is an even poorer option.........but that is a very different application with different priorities than a homestead partial/emergency backup system.

 

[viking]

When I asked Grape Solar about tracking, just with manual adjustments for sun angle, they told me it was unnecessary, just put the solar array to the angle that aligns with the parallel you live on, it's also important to have panels that have high voltage output, by using MPPT solar controllers they will allow higher charge levels throughout the day. We get decent charge amps even when the array is shaded by a large maple tree. I'd say that the average array voltage output throughout a sunny day is 80 VDC, the output drops to 60 to 70 volts just before the sun drops below the mountains, high voltage output panels make a huge difference in extending the charge time for each day, what amazed me was the kind of voltage we were getting on cloudy, rainy days.

 

[UrbanHunter]

Spent yesterday installing the frame for the new solar panels to the raised beds, made the adjusters to I can do the aligning by just removing 2 bolts. Then using old wood I started making a battery box. The box is actually larger than I currently need, but it gives me room to grow.... The controller will mount on the outside of the box and be covered by the lid, the inverter will mount to the other side of the box and also be covered by the lid. The box will sit on a ledge just outside my back door and the lid will be at about 30", so I can use it to hold things as I go in and out. The pair of solar panels I ordered have been delayed by a couple of weeks so that will give me more time.

I keep getting the feeling that when the SHTF comes you will not be able to find the equipment you need to build a backup or even buy a generator....

 

[Hardcalibres]

..........

I keep getting the feeling that when the SHTF comes you will not be able to find the equipment you need to build a backup or even buy a generator....

All the survivalists have that feeling, at least to some extent, their whole lives.

But even with that mindset, the current times make most of us feel (even more so) that one morning, we will wake up, and all you have is all you will ever have.

That background has made me buy a bunch of backup parts like more controllers and panels - mostly to make sure I can keep the gear I really need, running for a long time.

I have also been setting up an inshore and near shore small fishing boat and fishing gear (even though I haven't really done a lot of fishing in the past). That system provides both another food source and a remote mobility capability.

Filling in gaps is always good........but it is hard to shake the feeling that time is running out.

 

[UrbanHunter]

Today my 2 solar panels arrived, I can now load up the frame that I made, it will hold 400 watts and will be feeding my new battery box (it was made with recycled wood), I have been doing a little on the box wiring each night. I have 3 batteries sitting in it and can re-arrange them to evaluate how the cable runs will be for the different strings of batteries, I am hoping to have 6 batteries ready to go when I switch things on this Saturday and there is room for 3 more. That will give me 12+ hours of operation for the wife's oxygen machine. The inverter I am using has a built in automatic transfer switch so I can hook the inverter up to a generator and run the oxygen machine off a generator while the batteries are recovering off the solar (no change in the inverter electrical runs).

 

[viking]

I keep getting the feeling that when the SHTF comes you will not be able to find the equipment you need to build a backup or even buy a generator....

believe me, you are far closer to the truth than you think, I'm in the process of putting some things together for a dear friend of ours for a backup water supply in case the grid goes down. She, her daughter and son-in-law have a good well, but I told her to get a large above ground tank, she got a 1,500 gallon tank and I'm setting up the connection to tie it into their existing water system. She ordered four 100 watt solar panels with a PWN solar controller, which I may talk her into changing out for an MPPT type, but here's the kicker, when she tried to find the batteries I told her to get, no one had them in stock, other than some used batteries from Interstate Battery. I told her to go ahead and order some new batteries. Cosco stores in our area had no GC-2 batteries, that's where we bought 20 for our storage banks in 2013. In looking for what was needed for her water system, some of the prices really upset her, just the core charges for the batteries around here is $27. She also wanted extra power to run a few things in her small home and when I told her the cost of a good low end quality inverter it shocked her. The system I'm setting up for her is very close to what I installed in our motor home, I know what it's capable of doing and it would be just what she wants, but finding the odds and ends to put this system in operation is rather frightening, considering how much has changed since we put our emergency solar backup system in operation. As far as I'm concerned, we are already in the beginning stages of a real SHTF situation, it may be tough for beginning prepares, but doing something is better than worrying about whether you can do anything at all, just do what you can and make sure you start with the most important, food and water.

 

[UrbanHunter]

believe me, you are far closer to the truth than you think, I'm in the process of putting some things together for a dear friend of ours for a backup water supply in case the grid goes down. She, her daughter and son-in-law have a good well, but I told her to get a large above ground tank, she got a 1,500 gallon tank and I'm setting up the connection to tie it into their existing water system. She ordered four 100 watt solar panels with a PWN solar controller, which I may talk her into changing out for an MPPT type, but here's the kicker, when she tried to find the batteries I told her to get, no one had them in stock, other than some used batteries from Interstate Battery. I told her to go ahead and order some new batteries. Cosco stores in our area had no GC-2 batteries, that's where we bought 20 for our storage banks in 2013. In looking for what was needed for her water system, some of the prices really upset her, just the core charges for the batteries around here is $27. She also wanted extra power to run a few things in her small home and when I told her the cost of a good low end quality inverter it shocked her. The system I'm setting up for her is very close to what I installed in our motor home, I know what it's capable of doing and it would be just what she wants, but finding the odds and ends to put this system in operation is rather frightening, considering how much has changed since we put our emergency solar backup system in operation. As far as I'm concerned, we are already in the beginning stages of a real SHTF situation, it may be tough for beginning prepares, but doing something is better than worrying about whether you can do anything at all, just do what you can and make sure you start with the most important, food and water.

Batteries are my weak spot, I have been buying them 1 every payday, today I am making all the connections in the battery box. I ended up going with 100AH group 29DC batteries, because 1) I could get them, 2) I could carry them by myself, 3) I could afford them at $110 each and 4) the 2 old ones I used on the small box have lasted for over 5 years and they are still doing okay. Once everything is working I will start saving up for a set of "good" batteries, based on the prices I am seeing it will only take me about 2 years to save up enough, 4 if you count inflation......

I started with the system your friend got but I only hooked up 2 of the panels to see how they would work, I ordered a few more and the MPPT controller as I could afford it. I was lucky enough to buy a pure sine inverter at a good price (I did get a back up) years ago, it has been on the shelf waiting for me to get my act together.

The 400 watt frame is now aligned, loaded, and wired, today I am finishing the battery box and hooking up the inverter and controller. I plan to let it charge the battery bank for at least a day before I start applying loads.

 

[UrbanHunter]

The battery box is now functioning, 22 Amps in... Verified the inverter is working properly... so now I can move on to the next project:

 

[viking]

The battery box is now functioning, 22 Amps in... Verified the inverter is working properly... so now I can move on to the next project:

Looks good, nice job, what's your peak sun voltage? Depending on where the solar array is placed to where the battery box will be I might consider doing a series/parallel hookup for the panels and use the higher DC voltage to keep voltage drops between them to a minimum, I will definitely then use an MPPT controller, I'm really sold on what they can do.

 

[UrbanHunter]

Looks good, nice job, what's your peak sun voltage? Depending on where the solar array is placed to where the battery box will be I might consider doing a series/parallel hookup for the panels and use the higher DC voltage to keep voltage drops between them to a minimum, I will definitely then use an MPPT controller, I'm really sold on what they can do.

The total run is 30', I saw a little over 85 volts at the battery box today, I am using an MPPT on the big box and one of the cheap units on the small 200 watt box (most likely the same controller your friend has), the big box can hold another 3 batteries and I have the stuff to finish making the cables for that tomorrow. I wish I had the remote switch for the older AIM's inverter I am using as the switch is on the back side. I have a west facing overhang above the battery box area where I could add an additional 500 watts of panels in a pinch, but right now I want to get comfortable with using this setup. Anyway, I am trying to identify a good trial load for it starting tomorrow. The batteries are all over 13 volts so I think things are leveled out.

 

[UrbanHunter]

Today everything is running, I am powering one bank of my indoor grow lights and am still charging the batteries, so I am good for now..

 

[viking]

My friend is having some real problems finding deep cycle batteries and those she is finding are ending up twice the price they were earlier this year, 245 amp-hour batteries are going for $200 a piece plus a hefty core charge, 205 AH Costco batteries may be months out for attainment and probably their prices will be jacked up, I'm thinking, boy would I ever be in trouble if I had to replace any batteries in our backup system.

 

[UrbanHunter]

My friend is having some real problems finding deep cycle batteries and those she is finding are ending up twice the price they were earlier this year, 245 amp-hour batteries are going for $200 a piece plus a hefty core charge, 205 AH Costco batteries may be months out for attainment and probably their prices will be jacked up, I'm thinking, boy would I ever be in trouble if I had to replace any batteries in our backup system.

Hey @viking just being nosy how big an inverter did you go with?

I had an older AIMs 1250 watt pure sine inverter with a built in transfer switch and it works okay. When the inverter is on stand-by (running and no load) it draws 0.8 amps but if I hood up to house power the inverter shuts down and house power is delivered to my load... I got lucky and found it on close out years ago and have used it indoors with 200AHs of batteries as a UPS for the O2 machine but it would only cover about 4 hours and I had to keep the batteries charged using a trickle charger, but it would buy me enough time to get the generator running... I made it after breaking a pull cord in dark in the middle of a freezing rain, I figured it was enough to get me to daylight....

Now they make the inverters with the transfer switch and a built-in battery charger which would be nice with a small bank of LifePo4 batteries, you could put the whole mess in a small cabinet next to the load. But the inverter/charger units run from about $900 up depending on the wattage and the 12V LifePo4 batteries would be about $4/ AH and the thought of dropping $2500 on something for a SHTF event is a little out of my price range now.

On my little solar power system I have decided that I should have made my frame to hold 5 panels instead of 4, the 40A MPPT can handle 100 volts in and 5 panels would be just that and if it is overcast it would have given me just a little more juice. HD sells 10' 2X4s and they would be great for making a new frame, the way I built my frame I could make a new 5 panel version and swap it out easy enough, when I have so extra time... The supports, adjustment legs, and swing arms are all attached to the frame by simple wood screws so it will un-build easy..... It might be worth me ordering another pair of 100 watt panels from renogy. But the wife will not like it.....

 

[dunewalker]

The battery box is now functioning, 22 Amps in... Verified the inverter is working properly... so now I can move on to the next project:

Nice rack! I like seeing different versions of wood racks. My neighbor built his with logs/poles. Only concern with yours is the difficulty getting snow off, with the raised edges.

 

[UrbanHunter]

Nice rack! I like seeing different versions of wood racks. My neighbor built his with logs/poles. Only concern with yours is the difficulty getting snow off, with the raised edges.

The only edge that is above the edge of the panel is the top and it actually covers the top 1/4" of the panels; each panel is only held in by 2 screws and washers at the bottom. The panels are actually just even to 1/16" above the frame, they are supported from the bottom by 4 rails. I can walk up to the south edge and use a broom to pull the snow off. As the sun angle lowers I will continue to adjust the panels, they will be almost vertical (70 degrees) so the snow will want to slide off the front.

 

[dunewalker]

Yes, I guess it's an illusion about the raised edges--good job! I leave my panels in a more winter-like angle, even in summer, mainly from being too lazy to bother flattening them as well as the fact that so much more power is produced in summer that it's a moot point if they're optimally angled or not. Of much greater value is the ability to turn the array during the day, even just 3 positions. Again, during summer it's moot if the batteries are full.

 

[viking]

Hey @viking just being nosy how big an inverter did you go with?

I had an older AIMs 1250 watt pure sine inverter with a built in transfer switch and it works okay. When the inverter is on stand-by (running and no load) it draws 0.8 amps but if I hood up to house power the inverter shuts down and house power is delivered to my load... I got lucky and found it on close out years ago and have used it indoors with 200AHs of batteries as a UPS for the O2 machine but it would only cover about 4 hours and I had to keep the batteries charged using a trickle charger, but it would buy me enough time to get the generator running... I made it after breaking a pull cord in dark in the middle of a freezing rain, I figured it was enough to get me to daylight....

Now they make the inverters with the transfer switch and a built-in battery charger which would be nice with a small bank of LifePo4 batteries, you could put the whole mess in a small cabinet next to the load. But the inverter/charger units run from about $900 up depending on the wattage and the 12V LifePo4 batteries would be about $4/ AH and the thought of dropping $2500 on something for a SHTF event is a little out of my price range now.

On my little solar power system I have decided that I should have made my frame to hold 5 panels instead of 4, the 40A MPPT can handle 100 volts in and 5 panels would be just that and if it is overcast it would have given me just a little more juice. HD sells 10' 2X4s and they would be great for making a new frame, the way I built my frame I could make a new 5 panel version and swap it out easy enough, when I have so extra time... The supports, adjustment legs, and swing arms are all attached to the frame by simple wood screws so it will un-build easy..... It might be worth me ordering another pair of 100 watt panels from renogy. But the wife will not like it.....

So far she's considering a Samlex 2,000 watt pure sine wave inverter, it has 4,000 watts surge power so it would allow for running a refrigerator and perhaps a small chest freezer. Whatever she gets, it will probably come from Don Rowe, they have the best prices, locally, for inverters. They had looked at a 2,000 watt modified sine wave inverter at Harbor Freight for under $200, but I happen to believe that motors and electronics run better and cooler on pure sine wave.

 

[UrbanHunter]

Today we had winds in the 50 to 60 mile per hour range.... Yesterday I adjusted the panels to align with the more winter like angle. So the panels were almost in a sail configuration, saw some vibration but no real movement. It was a good test, I switched the load on the inverter from the 300 watts on the growing lights to the 450 watts on the oxygen machine the inverter didn't seem to notice.... I have been monitoring my freezers and they don't draw that much on average so I could cover all of them for a few hours if I needed to... If I were to add about 600 watts more solar panels, I could cover everything on a sunny day.... But some days the sun don't shine and the wind don't blow...

All and all today was a good test, none of the solar panel frames moved (even the temporary frame stayed put) and I was able to cover all of the wife's medical equipment for about half a day, plus all my batteries were at full charge as the sun went down.....

I would strongly encourage you to help your friend measure what her fridge and freezers are actually drawing (they sell cheap kill-a-watt - like meters on Amazon for about $17). I know for me it really opened up my eyes as to what I could cover with the equipment I had.....

 

[UrbanHunter]

I was looking for information for using solar with grid backup (the reverse of what most do) and I ran across this you tube vid... The guy is a HAM operator and he has a lot of solar and uses it in a variety of ways, I'll bet he has a boatload of money invested but it was a very interesting watch..




One thing I would suggest is watching what Congress and Biden do over the next year, I am hearing a lot about zero emissions and I would not be surprised to see tax deductions being offered for Solar installs in the future.... Last time it was 30% so it might help if someone was already planing a project... But it is not here yet (but as a prepper type I like to be looking over the horizon).

 

[viking]

My friend lives in a small cottage and her daughter and son-in-law live in a fifth wheel trailer so their refrigerators are low amp draw. The nice thing about newer refrigerators and freezers is that the manufacturers labels generally have the run amps listed. Their major need is for powering a small water pump and that pump will run on 12 VDC. She has gotten her solar panels, as well as four 6 volt high amp-hour deep cycle batteries, the kit came with a PWM solar controller but I told her that she can get better battery charging with an MPPT controller and that's what she's planning to get, so when I set up her solar array I'll do series/parallel to take advantage of less than ideal solar days. This is the reason I don't like solar kits with voltage outputs that are barely above the needed voltage to charge the batteries, the average solar voltage of our system is generally above 70 volts, so even on low solar days, with the MPPT controller we get a good float charge and most often, if the grid drops out, there is more than enough power to run basics off of the 4,000 watt inverter.

 

[UrbanHunter]

Hey @viking if she bought her unit directly from renogy she should get "points" that can be converted into coupons, which can be used to reduce the cost of a future purchase. After all my experiences I wish I had gone with the largest MPPT that I could afford, the 40Amp unit is fine but based on my daily load I could easily use the 800+ watts that a 60A unit could offer at 12V. Then again you could have something similar with 2 40Amp units charging the same battery bank.

My growing station has now been using only inverter power for 2 weeks and I have seen my batteries get down to 12.1 volts on a cloudy day but I am only using 1 shelf right now, when all 6 of them are online I could see the need for more juice... The growing stations are being monitored by a Kill-a-watt meter, so I can have a clear picture of what I am drawing.

The battery bank is working fine and I got my hydrometer, so I will start checking and documenting my battery status monthly.

I have my little portable setup with the PWM only has 200 Watts of solar connected to it and it is charging the surviving 2 old 100AH batteries from my first battery pack (vintage 2013), their voltage is actually a little higher than the big battery pack, since I have no load on this unit I am using jumpers to provide a link between the two packs, it gives me a little more usable energy and lets me take advantage of everything I have at this time.

I do regret not making my solar panel frames out of 10' 2X4s, I could have squeezed in 5 panels in the same space and that would have pushed the 40A MPPT to it's upper limit, actually a little over 500 watts vs 480 watts, but I am seeing that we have a lot of cloudy days where I am getting no where near 100 watts per panel....

I did have a day where I had to switch my wife's oxygen machine over to the inverter, the way I have it set up I can easily connect the inverter to several loads including: the sump pump, the freezers, the oxygen machine, or the grow stations.

The nice thing is, I can do the transfers without having to leave the house.

 

[viking]

Our dear friend, daughter and husband are extremely limited for what they can do, so I've designed their system to get the best bang for the buck, their system will be a lot like what we put in our motorhome. The only batteries they were able to get a hold of are 255 amp-hour and that is very good, their 400 watt solar kit came with a 40 amp PWM solar controller, but I told them that they would do better to use a MPPT controller and it will do a better job on keeping the batteries topped off on cloudy or foggy days that are common to winter days in our region. I'm planning to make a compartment under the solar array to put the four batteries, solar controller, inverter, disconnect box, fuse box and an junction boxes. I'll try and get pics posted as I can. Doing things around this time of year is often not all that easy, considering winter weather conditions, thing is I'm trying to get them an emergency water system and a little electrical power for their small cottage and fifth wheel, I've told the daughter that what I have designed for them is a bare bones system that is also solid, it's something I'd do for us if I had to keep things to a minimum. Considering the cost of the array frame, batteries, controller, inverter, 12 volt water pump, 1,500 gallon water tank and other necessities, it looks like it's in the $3,000 range. What they were looking at before they asked me what they should do, would not have made them happy, in my opinion, it would have failed them just when they needed it the most. The people I've dealt with, like Don Rowe and Grape Solar, have provided some of the best pricing, locally, that I have come across and they are close enough to save hundreds of dollars of shipping when we can pick the products up ourselves.