Need Some Assistance Trying to Design a Very Small Solar Panel Setup

[hvacskills]

I set up a Gasoline Powered, 8500 Watt Generator,, for immediate usage, hvac & We are looking in to generating Our DHW via Solar Panels during the Summer, as well as powering several electrical needs.

I'm going Full Wood burner, as soon as I get my "Man Cave" Finished, & I'm "toying with" the idea of providing, or supplementing Our DHW with it. I'm also going to install a Packaged HP/ Gas unit, & since we're considered a Farm, we can get a 1000 gallon tank of Propane, although, the provider will not be happy, when they see how little is used.

The Grid down here, goes out when ever a Coyote Farts, let alone high winds come through, so in many ways, ... We've Adapted, & yet, ... I want much better, especially when considering that a Quake, Terrorism, Political strife, Market Crash & more could completely "Change My World".

[ga-hvac-tech]

Have not read the whole thread...
Couple of points:

Watts are watts... does not matter what voltage... watts are a measure of power.
Basic formula (Ohnm's law): V x A = W (volts times amps equals watts)
So 12 volts x 10 amps = 120 watts...
And 120 volts x 1 amp = 120 watts...
Make sense... grin

Remember to never load a gasoline generator above about 80% of rated 'continuous' output, regardless of surge capability.
And always mix "StaBil" in the gas can for the generator (I prefer to have a separate can for this)... and always change the gas at least 2x per year and run it for a while to be sure the carb stays clean. Otherwise... it WILL NOT start when you need it...

The watt-hours thingy is how much power you will need... in watts...
That is the key.

You can always 'load share'...
That means turn off one thing, while another is working...
Example: turn off the fridge while making your coffee or mirco-waving your frozen food...

If it were me... I would go heavy on the storage batteries... the less you take them down really low... the longer they will last. Golf cart batteries are designed to discharge and re-charge... probably a good compromise between quality and cost.

Your inverter needs to be rated for more power than you plan to use also...
Harbor Freight has some inverters cheap... might look at those.
The sales guy at the local HF store... said the truck drivers buy them and use them on the trucks running over the road... power a TV, elec heater, coffee pot, microwave, etc...
BIG trucks have 200-250A alternators... some are 24V

Hope this helps...
Grin

[hvacskills]

Have not read the whole thread...
Couple of points:

Watts are watts... does not matter what voltage... watts are a measure of power.
Basic formula (Ohnm's law): V x A = W (volts times amps equals watts)
So 12 volts x 10 amps = 120 watts...
And 120 volts x 1 amp = 120 watts...
Make sense... grin

Remember to never load a gasoline generator above about 80% of rated 'continuous' output, regardless of surge capability.
And always mix "StaBil" in the gas can for the generator (I prefer to have a separate can for this)... and always change the gas at least 2x per year and run it for a while to be sure the carb stays clean. Otherwise... it WILL NOT start when you need it...

The watt-hours thingy is how much power you will need... in watts...
That is the key.

You can always 'load share'...
That means turn off one thing, while another is working...
Example: turn off the fridge while making your coffee or mirco-waving your frozen food...

If it were me... I would go heavy on the storage batteries... the less you take them down really low... the longer they will last. Golf cart batteries are designed to discharge and re-charge... probably a good compromise between quality and cost.

Your inverter needs to be rated for more power than you plan to use also...
Harbor Freight has some inverters cheap... might look at those.
The sales guy at the local HF store... said the truck drivers buy them and use them on the trucks running over the road... power a TV, elec heater, coffee pot, microwave, etc...
BIG trucks have 200-250A alternators... some are 24V

Hope this helps...
Grin

[BBeerme]

No but some things are like buying a Nautilus rather than an Edge. Sometimes you want to do things just because you want to. <g>

I built an array of hydronic solar panels to heat hot water for my NJ house. Some part of it was that I wanted to and another part was that I wanted to do it with scrap for the most part.

I like to imagine that having 160 gallons of 120º solar heated water feeding my tankless HWH saves me operating costs - but I really don't know as I've never run the numbers. And yes; you are correct; on cloudy or snowy days the collected BTU's are less and sometimes zero. But I don't look at what I don't get - I look at what I do get. And that is Not zero. <g>

And more in line with your actual thought is that I specifically didn't build PV solar because I don't know how to build PV panels. My general interests have been in developing the skills to move heat around. So I started with what I know; pumps ands pipes and fluids and wires and controls.

Wait; you just made me remember How I came to start on these projects! <g>

I originally wanted to design a solar heat powered AC system for cooling my house. I kept fiddling with the numbers and they were always too big. I couldn't figure out how to collect enough heat to generate enough cooling for all the cooling my house required.

So after a while I sat back and mused: Damn! If only I needed less cooling . . . . .

And a light went on - how can I reduce my Need for cooling?

So I stopped working on the thermal-powered cooling system and started working on improving the envelope. I added white 4-R siding, sealed, and insulated, and so forth. Then I replaced 14 tons of asphalt roof shingles with 1/2 ton of white solar reflective aluminum standing seam roofing.

And suddenly I didn't need six tons of air to cool my house - instead I needed just over 2 tons.

But . . . . the reduction in operating costs then made the thermal powered solar cooling system economically impractical. So I never did it. <g>

How's that for irony? <g>

PHM
------------

[hvacskills]

this is going to be a bit of a project, even if it is just a 1,200 watt supplemental / back up system .... not as if you can just throw a few solar panels on the roof and plug a few things in and be done .... after you get an idea what needs to be accomplished you have to fine tune that idea, figure out how you want the system to operate and then select the equipment .... then there is the whole logistical aspect of how and where to locate everything and how to hook everything up ... going to have to make a roof repair, cut a few holes in walls, relocate a few water lines, battery box ( might go with sealed, adds options ), install a sub panel ....

[lkapigian]

Have you checked with the local utility and building department? The utility will Have to come change your meter, you may Have to submit a plan ...perfect world 4 panels if you have them,due south and perfect geographical longitude ...You can have the inverter on the panel or separate ...lots of ways around a barn

Harbor Freight stuff probably won't do your fridge

[BBeerme]

No mention of tying into the grid, just a stand alone system.

But if it were tied into the grid, there could be a pay back that may pay for the install. In time.

Have you checked with the local utility and building department? The utility will Have to come change your meter, you may Have to submit a plan ...perfect world 4 panels if you have them,due south and perfect geographical longitude ...You can have the inverter on the panel or separate ...lots of ways around a barn

Harbor Freight stuff probably won't do your fridge

[lkapigian]

No mention of tying into the grid, just a stand alone system.

But if it were tied into the grid, there could be a pay back that may pay for the install. In time.

I would, easy peasy ..plus get the 30% federal credit on the cost

Around here you you would not be able to tie into the panel without contacting the utility

[DavidDeBord]

No mention of tying into the grid, just a stand alone system.

But if it were tied into the grid, there could be a pay back that may pay for the install. In time.

That is Absolutely TRUE BBeerme, ... But, awhile back, a long time member here in the group, went off on a Moronic Rant about "People getting killed", "Tying in to the grid being against the Law", & more, when I stated that this could be done. SMH

Tis' Good to see that Yu are aware of a H.O. generating Electricity for their usage, & selling the excess to the local Utility, via tying in to their Grid.

[BNME8EZ]

PHM mentioned "net zero", I see this as a loosing proposition. The cost of the equipment is high enough without adding the extra stuff you need to put power back on the grid which is what it necessary to go net zero.

We have had a strange winter this year. One day -0 the next near 50 or above. It has been a roller coaster ride the whole winter while being the 2nd snowiest winter on record (more global warming). My utilities right now are not enough to justify the project, last months utilities were under $200 with a good part of those being water, sewer, trash pick up and fees/taxes so maybe $100 give or take for electricity and NG. The one caveat to this is we rarely run outside lights at this point, which we would like to run to highlight the house and different aspects of the landscaping as well as light a flag pole that will be going up in the spring. As I see it If I can run these lights, cuts some of the house lighting and cut part of the heating load with this project then it will be worth it. I checked into a solar company, they wanted 10k for a system that is so over the top and ties into the grid which is exactly opposite of what I told them I wanted. I figure the material should be less than $5k for the PV, the hydronic seems to be harder to find info on. I have come up with a design for my own panel which would be interesting to see if it would function better than the current types. I would like to make a prototype and test it but at this point I don't see where there is a big enough demand for it.

[lkapigian]

By 2020 all new residential construction in California will be Net Zero Energy

[hvacskills]

PHM mentioned "net zero", I see this as a loosing proposition. The cost of the equipment is high enough without adding the extra stuff you need to put power back on the grid which is what it necessary to go net zero.

We have had a strange winter this year. One day -0 the next near 50 or above. It has been a roller coaster ride the whole winter while being the 2nd snowiest winter on record (more global warming). My utilities right now are not enough to justify the project, last months utilities were under $200 with a good part of those being water, sewer, trash pick up and fees/taxes so maybe $100 give or take for electricity and NG. The one caveat to this is we rarely run outside lights at this point, which we would like to run to highlight the house and different aspects of the landscaping as well as light a flag pole that will be going up in the spring. As I see it If I can run these lights, cuts some of the house lighting and cut part of the heating load with this project then it will be worth it. I checked into a solar company, they wanted 10k for a system that is so over the top and ties into the grid which is exactly opposite of what I told them I wanted. I figure the material should be less than $5k for the PV, the hydronic seems to be harder to find info on. I have come up with a design for my own panel which would be interesting to see if it would function better than the current types. I would like to make a prototype and test it but at this point I don't see where there is a big enough demand for it.

I have no intention of tying into the grid either ....

still watching youtube videos to try to get an understanding about all of this stuff ... talking about youtube, give some people a camera and they can sure carry on

there are a few things I can start prepping while I am figuring on the final design .... I understand why you were wanting to follow this thread ....

[lkapigian]

I have no intention of tying into the grid either ....

still watching youtube videos to try to get an understanding about all of this stuff ... talking about youtube, give some people a camera and they can sure carry on

there are a few things I can start prepping while I am figuring on the final design .... now I see why you were wanting to follow this thread ....

If you want to be off the grid you , run separate dedicated solar circuit

I think you are over thinking this, the power company will come change your meter and put you on a different program, it's free....panels are cheap, you can do an inverter on the panel ( each) or 1 inverter below, rack systems are cheap...in our area , solar permits under 10kw require no review, permit is over the counter....send youself a bill and take the 30% Tax Credit

[hvacskills]

If you want to be off the grid you , run separate dedicated solar circuit

that is the plan, with batteries for back up, the battery aspect sort of complicates everything when you know nothing about batteries or a solar system ( capacity, type, sizing )

[lkapigian]

that is the plan, with batteries for back up, the battery aspect sort of complicates everything when you know nothing about batteries or a solar system ( capacity, type, sizing )

No real need for battery where I am, but if you are stationary ( not like Mobile in that video) you have more latitude with the ability to have a larger bank whether it be Lithium or Lead acid
While superior energy density is not critical for stationary applications, it is essential for electric vehicles and portable electronics. Increased energy density greatly improves the deployment and installation process for stationary energy storage.


https://medium.com/solar-microgrid/b...n-1d37a1998287

[ga-hvac-tech]

that is the plan, with batteries for back up, the battery aspect sort of complicates everything when you know nothing about batteries or a solar system ( capacity, type, sizing )

As usual...

Folks that make videos often do not tell the whole story...
*LiOn batteries... will get VERY hot... when discharged or charged too fast...
THIS is the reason for the LiOn fires... like the infamous Samsung Note 7 phone... and the tail end of the Boeing 787 Dreamliner.
*LiOn batteries should NEVER be taken below about 20-25%... it damages the internal structure of the chemicals... which lowers recharge capacity... as well as increasing the potential for a fire.

I have shaken my head for years over videos...
And it is just down-right scary... that folks think they are getting the whole story in a video...
They are NOT!

[hvacskills]

PHM

probably appreciate this video

[hvacskills]

*LiOn batteries should NEVER be taken below about 20-25%... it damages the internal structure of the chemicals... which lowers recharge capacity... as well as increasing the potential for a fire.

yeah, really clueless about the battery decision ... was thinking standard lead acid golf cart batteries, then watching videos about the actual amperage produced is not very impressive ... then you have the maintenance on them, guess you are suppose to check the electrolytes in the solution once a month or so and then occasionally equalize them ( charge them with no load at a high rate to drive chemicals off of the plates and back into the solution, or something like that ), so still have no idea what to do about batteries ..... I am really liking these 18650 battery packs though, really impressive, just no sure I would want a bunch of them in the basement, but supposedly it can be done safely ..... not even a week into this so hopefully get a better understanding as investigating more

[Lawrosa]

do your self a favor. Get a transfer switch 6 circuit for what you want to power. Hook this up. This can run off generator or inverter. ( problem with the gen you bought its 120v only. A 240 gen will serve you best)

https://www.electricgeneratorsdirect...SD/p95053.html

But there is only one 120v transfer switch I am aware of. Only gives 4 circuits.

https://www.electricgeneratorsdirect...14A/p1109.html

You can then run 4 circuits off your gen..

Now the solar on the cheap.. This is how I run my RV off the grid.

You need charge controller.. And you want MPPT not a PWN.

This is a good cheap unit. I have it

https://www.amazon.com/EPEVER-Contro...gateway&sr=8-3

You want to get 4 golf cart batterys. Hook two in series and the pair in parallel making 24 volts. This lets you use smaller wiring.

go to sams club or batterys and bulbs and get the 6 volt duracells 225 amp hours.

https://www.batteriesplus.com/productdetails/sligc115

Then you need 24 volt inverter.

Krieger 24V 2000 Watt Power Inverter

https://www.dcacpowerinverters.com/product/mr2000/

https://www.kriegermfg.com/product/mr2000/

Then two residential panels hooked in series.

At least 280 watts each. like this..

https://www.ebay.com/itm/LG-Solar-Panel-295-Watt-60-Cell-Mono-crystalline-New/283379510095?hash=item41fabc2b4f:g:Q2cAAOSwrhNcZH5 u:rk:3f:0

thats a start

[lkapigian]

For as low a wattage and you really only doing it for back up maybe a generator is a better fit for you