Feast or Famine, The off grid solar dilemma.

[Johneb]

It's different in united states. We by and large don't have a good recycling system but the restaurants still have to dispose of the waste oil on a regular basis. If they can't get someone to get it they have to pay to have it disposed of. Its tricky. The more rural the areas the harder it is to get rid of it for them reliably. Dumping it is frowned on and a royal pain for them on a regular basis. Finding someone that will contract with them aka free makes it a dream for them.

But for small time users its harder for them to find because of the deals they setup. Also in rural areas there a far less restaurants per mile. So basically more farmers and stuff wanting it and less supply.

Not to mention we have large companies now that have contracts with resteraunts for the bio added to pump diesel.

 

[Mattb4]

Facing famine this morning. After a day yesterday that started off nice and clear it went to clouds and occasional sprinkle by noon. Very little PV gain during the prime charging hours of the day. Woke this morning with my batteries low and the coffee maker starting caused my AIO to transfer to grid. The morning is stormy with rain so it will be a while before the sun will arrive to begin recharging my batteries.

No big problem, or so I thought. That is until the grid went away and I am back on my batteries with maybe 20% capacity. I did not anticipate a grid loss with the weather pattern. Do not know what caused the loss of grid and if it goes on for long I might be forced to start my generator. Funny thing was just the other day I was thinking of selling the generator because I have this Jim dandy solar stuff to carry me through any grid down scenario.

The low voltage alarm has just began, what a pain, it does not quit until battery voltage rises above the setting.

 

[Daddy Tanuki]

Facing famine this morning. After a day yesterday that started off nice and clear it went to clouds and occasional sprinkle by noon. Very little PV gain during the prime charging hours of the day. Woke this morning with my batteries low and the coffee maker starting caused my AIO to transfer to grid. The morning is stormy with rain so it will be a while before the sun will arrive to begin recharging my batteries.

No big problem, or so I thought. That is until the grid went away and I am back on my batteries with maybe 20% capacity. I did not anticipate a grid loss with the weather pattern. Do not know what caused the loss of grid and if it goes on for long I might be forced to start my generator. Funny thing was just the other day I was thinking of selling the generator because I have this Jim dandy solar stuff to carry me through any grid down scenario.

The low voltage alarm has just began, what a pain, it does not quit until battery voltage rises above the setting.

take that genset and get a propane conversion kit for it. no need to keep gas around that goes stale, and a bbq propane tank will last a long time on a smaller genset. a standard BBQ propane bottle runs my makita 5kw genset for quiet a long time... i never bother to fire up unless i can run it at 75% load to maximize charging and what not. (i have not used it since switching to lithium though.)

this is the company i bought from. https://www.uscarburetion.com/ they offer the snorkel kit which is the easiest to install. and works great for most gensets below 5kw

 

[Mattb4]

Got back from my morning walk (rain down to a sprinkle) and the Grid is back. I avoided having to resort to the generator by a shave, it being close. It would be nice to have my Honda inverter as a propane fueled unit. Having to drain the gas each August and replace is an annoyance.

I had hoped my battery capacity would have taken me further than a night, followed by a poor PV generation day and another night. I should have ran my aux. battery charger (12a on overnight timer) last night. Its purpose is to cover such situations.

 

[EastTexCowboy]

Got back from my morning walk (rain down to a sprinkle) and the Grid is back. I avoided having to resort to the generator by a shave, it being close. It would be nice to have my Honda inverter as a propane fueled unit. Having to drain the gas each August and replace is an annoyance.

I had hoped my battery capacity would have taken me further than a night, followed by a poor PV generation day and another night. I should have ran my aux. battery charger (12a on overnight timer) last night. Its purpose is to cover such situations.

I made it three days of rainy weather before going to grid once but that was early May and it was much cooler. Sounds like you could stand to add a little more battery.

 

[SamDeleted]

I have a redundant solar field. Panel strings, charge controller, battey/batteries at the ends of the solar strings connected to a DC Buss (DC coupled).

With the more volatile chemestries out away from shops or homes, an insulated box with minor heat is all that's needed to be more than 'Reasonably Safe' with any chemestry.

I'm perfectly aware that a lot of city dwellers don't have room for ground mount panels, and I'm aware DIY batteries wouldn't pass city code inspections even if they were off grid, city dwellers being the least likely to be off grid...

I have no such restrictions, and being off grid I savaged what I could afford, and built within the education base I have.
It's not 'Code', it's not 'Perfect, it's not 'Pretty'...
However it is functional, redundant, and it's mostly 'Safe', can fail right where it's at and won't damage anything else, like burn the house or business down.
30 years of experimentation and education as I find it.

I can't say it's fool proof, the 'Great Coyote Fire' of 2015 proves there are some things that CAN happen. A coyote managed to get into a pouch cell battery box, the fire was mostly contained to the coyote, but there you have it. How a coyote got the lid off the battery box is still a mystery...

Scorched a post, damaged a panel, smoked the battery/box/charge controllers, but damage was limited to that ONE box/panel, more or less.

Since weight/space really isn't an issue for me, refractory cement (like in fire safes) and rock wool in common metal cabinets work just fine for me.

In 30 years I've used everything from military surplus aluminum or steel cabinets, to refrigerators to the big office copier cabinets, it really doesn't matter where the cabinet comes from...

Indoors it's LiFePO4 batteries as fast as zi can find/build them. With a big, long DC Buss they act more like capacitors than batteries internally in the system...
Sudden Big Amp draws in the shop especially, so it's the best fit for the application.

I'm sure if I had neighbors, they would complain the cabinets 'Didn't Match' or didn't have designer labels...
When I started 30 years ago, there weren't any 'Designer Labels', and like an old tractor the paint has faded on, they still get the job done just fine.

With DIY, it's about how it works, not what the neighbors think is 'Cute' or 'Expensive/Designer'.

Are there any pics around from your cabinets

I like the redundancy

 

[Mattb4]

I made it three days of rainy weather before going to grid once but that was early May and it was much cooler. Sounds like you could stand to add a little more battery.

Problem with adding more battery is than I would need more PV to charge. The vicious cycle of design, find components and build would begin all over.

 

[EastTexCowboy]

Problem with adding more battery is than I would need more PV to charge. The vicious cycle of design, find components and build would begin all over.

That's not a problem. That's our life now. Embrace it!

 

[LydMekk]

After 3 days with rain the weather is finally clearing up now.
Wasn't too bad - battery got down to 35ish.
This afternoon almost back to 90.
The grueling fear of the grid abates...

 

[SeaGal]

Problem with adding more battery is than I would need more PV to charge. The vicious cycle of design, find components and build would begin all over.

previously said....

As I prepare to mount my last solar panels and hook them up it strikes me that I have reached the point where there is nothing left to do. The months spent investigating, researching, planning, building, wiring, tearing out, re-doing and just generally occupying my attention, are drawing to a close once the final setup is up and working. At this point it just transitions to routine maintenance and repair. My system meets the needs I am putting it to. It works.

Sorta sad

... think you've found a cure for your own sadness ?

 

[Mattb4]

... think you've found a cure for your own sadness ?

Bad show holding me to previous statements.

How did it go.. “A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines." -Emerson


ETA: In case anyone missed it I was poking fun. Sometimes humor does not come across as intended.

 

[wattmatters]

No big problem, or so I thought. That is until the grid went away and I am back on my batteries with maybe 20% capacity. I did not anticipate a grid loss with the weather pattern. Do not know what caused the loss of grid and if it goes on for long I might be forced to start my generator.

I have 20 kWh of sealed lead acid ex-data centre backup batteries (in very good condition) which are kept at float for exactly this purpose. My LiFePO4 does the normal daily cycling duty while the lead acid is kept topped up ready for that scenario.

Should that turn out to not be sufficient and the solar PV is unable to recharge enough, then the generator can come out for some supplemental charging. It doesn't need to be a super powerful unit. My Yamaha can comfortably supply 2 kW and that's plenty for my supplemental recharging needs.

 

[Zwy]

It is what it is.

Up to a 10 year wait for a ramp or wheel chair lift to your house if you need one, artifical joints so worn out they find heavy metals in your tissues, the list goes on...

Improvise, Adapt & Overcome.

Semper Fi

Some don't overcome, check the suicide rate among vets. I had a 'certified' mental health counselor (trying to tell me the pain from 5 breaks in my back was all in my head) tell me suicide WAS an option.

Just more nonsense to overcome...

Yes, mental health at the VA can be a real trip.

Now I'm trying to grow citrus at 38.5°N and figure out which home canned pasta sauce I like best! The important things in life...

Citrus? Well, you are in luck, ran across this a few months ago, just loved his enthusiasm and ideas.

 

[Zwy]

Got back from my morning walk (rain down to a sprinkle) and the Grid is back. I avoided having to resort to the generator by a shave, it being close. It would be nice to have my Honda inverter as a propane fueled unit. Having to drain the gas each August and replace is an annoyance.

You need some Pri-G. https://www.amazon.com/gp/product/B009TWQAOA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It works, not like the Stabil. I keep over 700 gallons of gasoline here in storage for equipment and vehicles. Some of it I paid $1.40/gallon for it.

I had hoped my battery capacity would have taken me further than a night, followed by a poor PV generation day and another night. I should have ran my aux. battery charger (12a on overnight timer) last night. Its purpose is to cover such situations.

You need more battery.

 

[timselectric]

If you are charging your current batteries to 100% daily. You have enough solar to add more batteries.

 

[kundip]

Designing an off grid solar solution always seems to end up being a feast or famine situation. You either have more potential than you can use or you fall short of having enough due to battery capacity, Season, weather or unexpected loading. There is no question that the AIO's have helped with this by being able to utilize the grid (or a generator) to make up for shortfalls but since excess can not be sent to the grid for later use, or a compensation payment amount, PV production has to sit idle. Those people that are grid tie never encounter this since they upload to the grid whatever their panels produce in excess of house loads.

You see many folks trying to find a use for extra PV capacity by either manual load addition or automatic dump loads. Other folks add more battery storage so that they can go longer between PV production intervals. Most of the solutions bring their own problems. One being if you get dependent on the "dump" load you added than the times of lower PV production puts you further in the hole. In the case of added battery storage you can reach the limit of not having enough PV to charge back up your battery in a reasonable time frame if it gets drawn down too much. More PV than puts you back into a possible under utilized potential.

My latest setup allows me to manually transfer a hot water heater on if I see my batteries charged by midday. Or I can switch a window AC to run.

Curious of how other off gridders handle the feast and famine times.

Feast:
Creating the problem of way too much energy is the first post. It means you can have the fun of figuring out how best to use it. I set up two old 2400 watt fan heaters with WiFi timers. They were only needed 10AM until 2PM to shave the top off the peak export time.
Initially I used 2400W from one & 1200W from the other. Bus as I have purchased LiFePo4 batteries ( normally for well under 1/2 price) I now just use one heater at 1200W from 11AM to 13PM.
I will figure out how to use the rest of the excess as time goes by.
Famine.
You cannot dodge the grid IMO.
Not unless you just don't use electricity when you don't have it.
I have found that about 10% grid independence during winter is the best I can do relatively cheaply.
To cover that 10% from the grid you need a lot more batteries & panels to cover the gap by comparison to the first 90%
Solutions to this are not available yet. IMO

 

[SamDeleted]

Famine.
You cannot dodge the grid IMO.
Not unless you just don't use electricity when you don't have it.
I have found that about 10% grid independence during winter is the best I can do relatively cheaply.
To cover that 10% from the grid you need a lot more batteries & panels to cover the gap by comparison to the first 90%
Solutions to this are not available yet. IMO

Wind turbine could make up some in winter , also hydro if you're blessed with running water


And an internal combustion generator of course!

 

[upnorthandpersonal]

Wind turbine could make up some in winter

Unless you have literally ideal circumstances, don't use a small wind turbine. The maintenance, the ice build up, noise, them tearing themselves apart in high winds, the need for a dump load, and the fact that small wind turbines just don't generate much to speak of makes this just a headache.

 

[JeepHammer]

Are there any pics around from your cabinets

I like the redundancy

I'm on android (can't recommend) and way from home. I'll see what I have when I get home.

Not much to it, plywood in the back for charge controllers, I mount them in parallel so I can switch from one to another (they are cheap) and the battery.

Since my stuff is non-propritary, I buy charge controllers for the battery type/chemestry.

The only 'Extra' thing I do is copy the instructions and seal them up in a vacuum freezer bag, leave them taped in the door. Having instructions and a wiring diagram handy when things change 5 or more years down the road saves a lot of time.

 

[SamDeleted]

I'm on android (can't recommend) and way from home. I'll see what I have when I get home.

Not much to it, plywood in the back for charge controllers, I mount them in parallel so I can switch from one to another (they are cheap) and the battery.

Since my stuff is non-propritary, I buy charge controllers for the battery type/chemestry.

The only 'Extra' thing I do is copy the instructions and seal them up in a vacuum freezer bag, leave them taped in the door. Having instructions and a wiring diagram handy when things change 5 or more years down the road saves a lot of time.

Cool no rush


I was wondering, if you don't mind , how do you parallel together all the systems ?

Is it DC before the inverter . How to you get over joining batteries of different chemistries

 

[EastTexCowboy]

You need some Pri-G. https://www.amazon.com/gp/product/B009TWQAOA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It works, not like the Stabil. I keep over 700 gallons of gasoline here in storage for equipment and vehicles. Some of it I paid $1.40/gallon for it.


You need more battery.

I'm right there with you on the Pri G and Pri D. Way better than Stabil or any of the others. I use mostly diesel and it works even better on it than gas.

 

[JeepHammer]

take that genset and get a propane conversion kit for it. no need to keep gas around that goes stale, and a bbq propane tank will last a long time on a smaller genset. a standard BBQ propane bottle runs my makita 5kw genset for quiet a long time... i never bother to fire up unless i can run it at 75% load to maximize charging and what not. (i have not used it since switching to lithium though.)

this is the company i bought from. https://www.uscarburetion.com/ they offer the snorkel kit which is the easiest to install. and works great for most gensets below 5kw

Can't agree more.

I started on a little gasoline, switched to bigger diesel/propane when I needed the generator (welder) for business. About $450 extra for the dual fuel add on for a BIG welder/generator.

CNG/LPG never goes bad, and it doesn't rot fuel systems. Runs cleaner too.
From 20 pound to 100 pound bottles you can manage yourself, some suppliers will plunk down up to 350 pound bottle for free when you buy from them.

As long as I contract exclusively with a supplier, they will furnish the tanks for free, but not everyone does this.

I buy in summer when prices are down, have a big enough tank to keep me all winter. The more load the solar takes over, the less we use...

 

[Mattb4]

I'm right there with you on the Pri G and Pri D. Way better than Stabil or any of the others. I use mostly diesel and it works even better on it than gas.

I only use non ethanol gas. I consider additives such as Pri G as a waste of good money. The only gas additive that actually worked was lead. For diesel you do need an anti-algae additive for long storage periods and a way to separate water.

Consumer gas additives often contain ethanol. Seems like a bad idea to buy ethanol free gas and end up adding it. It does serve a purpose as a dryer* as it allows moisture in the gas to be suspended in solution for safer combustion.

* Most gas dryers are wood alcohol or methanol instead of ethanol.

 

[Crowz]

I ran into a problem with stabil. I have been running it in about everything since I have like 40 vehicles and mowers and tractors etc to try to keep gas from going bad. The problem first showed up in my riding mowers. Its a gummy residue that clogs up the fuel bowl and the jets. I'm not sure if its happening in the larger vehicles but I had nothing but problems with that mower forming the crap and besides gas the stabil is all I used in it. Makes me a bit leery of the stuff now. Its been forming in weed eaters I have too.

I don't use additives in my diesels which I know can form algae from what Ive read but Ive never had an issue with the diesel stuff. I have one truck that has had the same fuel in its tank for 8 years or more now. I just move it around the yard to mow the grass so I've never run the fuel out enough to fill it in a bit

 

[JeepHammer]

Cool no rush


I was wondering, if you don't mind , how do you parallel together all the systems ?

Is it DC before the inverter . How to you get over joining batteries of different chemistries

Battery isolators. The batteries can dump amps on the Buss, but the Buss can't feed the batteries.

Should I want to charge a battery off the buss, it's a nice, cheap switch and 6 inches of wire to bypass the isolator.

It's basically a Diode.
A Diode is a one way gate valve for electrical current.

The isolater lets an battery contribute to maintain Buss voltage, but the Battery can't charge off of the buss. Charging is the job of the panels. Chargers maintian the specific battery voltage En Banc.

Everyone freaks out when I say, "Same Battery Voltage, More Or Less"...

With isolators it doesn't matter if one battery chemestry is one volt up or down from the rest. The one with the higher volt will simply feed until it's down to the same level as the rest, and as batteries discharge more and more batteries En Banc will contribute.

The BMS shuts down any battery that gets anywhere near it's lower limit, or gets too cold, so there is that line of defense. I FINALLY have enough panels & batteries i don't have to watch every Watt.

Yes, I loose a few watts to the isolator, I loose a few watts to the long Buss, it's insurance off grid I don't sit in the dark.
Dark is bad since I run my business and farm off the solar/batteries.

Batteries instead of backup generators...

I scrounge batteries from anywhere and everywhere, and the less you work Lithium the longer they last, where lead/acid has a finate lifespan from the time acid hits the plates.
Lithium will last as long as the seals hold.

So, BIG battery bank, as much as I can afford/scrounge...

By staying modular, I can also run whatever panels I find. I bought out a bankruptcy of a solar place, a crap ton of new (2017 complant) hardware including over a semi truck trailer of panels.

This didn't mean all the panels were the same size/output/manufacturer.

I can put like panels in a string, feed a charge controller/random battery. The entire solar field doesn't have to match.
When I don't have enough panels for a full string, they get parted out for stand alone lights, electric fence chargers, camera power supplies, etc.
Same with good cells in a failed battery...

Little charge controllers are $20... easy to put panels/cells out still working until there's nothing left of them.
The longer I use them, the more return on investment I get (and crap I don't have to do manually, like dig trenches all over 108 acres of property for electric lines).

If I want a light and/or camera way out over the river dock, all it takes is a tree or post, panel or two, a few cells, light and/or camera... no 1,000 yards of trenches, wires, etc.

Everybody's situation is different, use it if you can, if you can't it didn't cost you anything.