diy solar

diy solar

Low battery automatic transfer inverter (PROBLEM SOLVED)

That’s great! Using the bonus power well.


That is the right solution. Clearly you needed the storage, and because you’re using solar to enable savings in another area there is essentially no cost to you. It will break even in months.
400W is ok-ish to add a fridge. You might need more batteries, though.

Probably what you have going is maximum savings over minimum time (ROI) but no you have the power; adding to it a tad could be a fun hobby.
(what inverter?)

I’m hoping you have a pure sine wave inverter cabable of ~1200W (10A@120V) not a mod sine. Because a pure sine could maybe run your fridge with the sun out at ~400W of solar. So then you’re in reach of emergency grid replacement during outages.

I have and can run up to 700W of solar. No grid nearby. Been running on only 400W all summer.
It’s still weird in my head when I realize I just make coffee and such and don’t think about being careful with power consumption anymore.
My inverter is a modified sine wave inverter. I can pick up a cheap pure sign wave inverter but the cost, watt for watt is about 40 percent more. More expensive if I want the super whamydyne units.
 
I've finished the frame. It's a bit heavy but I can drag it about.
Folded:
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The 2 panels will be mounted on the horizontal (1x6) crossbars.

Frame open:
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Using hinges I can adjust the angle for summer/winter use. I just need another set of hasps for the winter setting.

Once I get the placement set I'll dig some holes for concrete, insert some threaded rod, drill the base and bolt it down. Until then I've got plenty of BFRs* to set on the base.

*BFR - Big Freaking Rock
 
My inverter is a modified sine wave inverter.

I've finished the frame. It's a bit heavy but I can drag it about.
Folded:
View attachment 62050
The 2 panels will be mounted on the horizontal (1x6) crossbars.

Frame open:
View attachment 62051
Using hinges I can adjust the angle for summer/winter use. I just need another set of hasps for the winter setting.

Once I get the placement set I'll dig some holes for concrete, insert some threaded rod, drill the base and bolt it down. Until then I've got plenty of BFRs* to set on the base.

*BFR - Big Freaking Rock
Nice!!! That will put my podunk frame to shame. I should be running over to Home depot soon to pick up the lumber, but mine will be....basic in operation. I see the hinges you talked about. Now I will probably use a single hinged mid mounted board to allow for tilt. I have enough space and wire so that all we have to do is simply lift the panel mount and rotate it 180 degrees to face either the morning or afternoon sun. I am fortunate to have a location that gets both morning and afternoon sun, the house nor the fences get in the way, the location gets a good solar track.
 
I hauled all that in my Nissan Versa with room to spare ?
My pickup retired when I did. It deserved it after hauling far too many BFRs

FORD - Fast Oversized Rock Delivery
scaled_full_a0a09378579c8d8a3ab4.jpg


I do tend to overbuild. But I wanted to make sure it didn't blow away.
The frame is a bit high to allow for snow. The panels will sit about 1.5 feet above ground level.
 
How so? I don't follow what you mean by battery to controller.

The relays are powered by the controllers lvd/lvr settings
Disconnecting the controllers from the battery and effectively shutting them off while sitting connected to open circuit solar panels isn't the most ideal approach to safely disconnect. This leaves your solar charge controller sitting, powered off, with (potentially) live high voltage feeds into them. I've seen it warned of many times throughout this forum. I think the primary reason being that you could fry your charge controller like this. There are probably other reasons. Anyway, maybe a relay on the panels to the controller for both hvd and lvd disconnect. Obviously, on LVD you would still have to disconnect the SCC; unless, you can simply turn the load switch off programatically on the scc (if that is indeed how you're using it).
 
I hauled all that in my Nissan Versa with room to spare ?
My pickup retired when I did. It deserved it after hauling far too many BFRs

FORD - Fast Oversized Rock Delivery
scaled_full_a0a09378579c8d8a3ab4.jpg


I do tend to overbuild. But I wanted to make sure it didn't blow away.
The frame is a bit high to allow for snow. The panels will sit about 1.5 feet above ground level.

Wind is mild here but my plan B if a storm does blow through is to simply lay them flat on the ground. The wind will rip apart my fences before it can get to the panels. Lord have mercy that is a big rock. LOL you look like you are preparing to build a pyramid, complete with wood rollers
 
Disconnecting the controllers from the battery and effectively shutting them off while sitting connected to open circuit solar panels isn't the most ideal approach to safely disconnect. This leaves your solar charge controller sitting, powered off, with (potentially) live high voltage feeds into them. I've seen it warned of many times throughout this forum. I think the primary reason being that you could fry your charge controller like this. There are probably other reasons. Anyway, maybe a relay on the panels to the controller for both hvd and lvd disconnect. Obviously, on LVD you would still have to disconnect the SCC; unless, you can simply turn the load switch off programatically on the scc (if that is indeed how you're using it).
That is way above my pay grade. I will try to learn a bit from this side bar thread.
 
Disconnecting the controllers from the battery and effectively shutting them off while sitting connected to open circuit solar panels isn't the most ideal approach to safely disconnect. This leaves your solar charge controller sitting, powered off, with (potentially) live high voltage feeds into them. I've seen it warned of many times throughout this forum. I think the primary reason being that you could fry your charge controller like this. There are probably other reasons. Anyway, maybe a relay on the panels to the controller for both hvd and lvd disconnect. Obviously, on LVD you would still have to disconnect the SCC; unless, you can simply turn the load switch off programatically on the scc (if that is indeed how you're using it).

I think you've misinterpreted my post.

I never said anything about shutting off the controller, that stays on 24/7.

The LVD/LVR controls relays which switch on/off a charger powered by mains at my desired voltages.
 
Well, got the panel frame built and the panels installed on it. This was podunk carpentry at its finest, but it works and the build seems strong enough. I will probably make adaptations along the way. I have tasked the wife to paint the frame with some white lacquer to help it weather the elements, adding an additional instruction to not paint the surface of the solar panels but since she was already talking about masking off the panel face and using spray paint instead of the paint can and a brush. Meh....whatever, as long as the important parts get protected. I still have not done an output power test but mostly because the temperature has been warm enough to make heating the house a light load (it is August after all) But Monterey can't go a week without diving into the 50's at night so the next time we have a good nights draw and a morning sun, I will check how much power is coming from the panels. I love my little Fluke AC/DC clamp meter, I can walk around with it and clamp wherever I want. The solar wires into the controller, from the controller to the batteries and even between batteries to see if have unity power distribution. I get the feeling that I am going to have to add a small electric space heater in the living room when winter gets here. Monterey never really gets that cold but it does occasionally reach down into the high 30's I don't care because I can be warm and comfy with just a couple of comforters, but wife needs the room to a little warmer in the winter. I swear she must be part reptile. In the end I guess no matter how much energy she pulls the plan B is always the transfer switch kicking in and saving the day. Edit: I will get around to snapping some pics...probably after the wife unit finishes the paint job.
 
So I noticed that when I was running just one battery the l00 watt load I had on it brought the float voltage down to 12.8 volts which is what I expected to see for a fully charged battery under load, but...since I double my capacity the loaded voltage stays at 13.1 volts and dropped down to 13.0 during the night, which is great but not what I expect the loaded voltage to be, assuming the two batteries in parallel would still read 12.8 volts full, what gives? Is it because 100 watts on a 200 Amp Hour battery pack is not enough to bring it out of floating conditions? Here is a quick couple of pictures of my unfinished panel frame. It is operational but needs a coat of paint and I am still deciding on what kind of tilt system to use. Right now I am using a piece of wood to simply tilt it the angle needed. I intentionally extended the wood out beyond the panels to act as kind of legs to keep the wires from being crushed while the unit is tilted or even laying flat on the ground.
 

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Bed Battery & Beyond ?
The voltage is beyond me but the project is coming along fine.
Chances are the load that is being put on the new super whamadyne is just not enough to bring it below the float voltage range. Which I think is a good thing. I start out the night at 13.1 volts and in the morning the voltage dropped down 13.0 with her running the electric heating pad all night. Could also be that my old battery while the same model number as the new took a few beat downs due to my testing on it and trying to figure things out. Who knows but I do know that I have power to spare and it's all automatic. To coin a phrase...Winter is coming and there will be the real challenge. The heating pad is great for her but eventually I will have to bring electric heaters into the mix even if it is to just turn them on long enough to break the chill in the house but hey, if it does drain the batteries down, as soon as they hit 12.3 volts it switches over to grid power that effectively maximizes the amount of power I can harvest from the sun and use at night. I will post a pic of the final panel mount, my son has come up with a couple of good ideas for tilting the panels, although my podunk ass seems happy to just use a tilt board. In the rare wind storm I will just lay the panels flat. I do have a weather station up and running so in theory I should be able to see a problem before it becomes one.
 
since I double my capacity the loaded voltage stays at 13.1 volts and dropped down to 13.0 during the night, which is great but not what I expect the loaded voltage to be, assuming the two batteries in parallel would still read 12.8 volts full, what gives?

1) voltage sag is sorta a percentage and is not linear. So you have more buffer against loaded sag.
2) It is not unusual for new lead acid batteries in good condition to ‘store’ above 12.8V. Mine are over 13 with no input somewhat often. Lifepo also have higher static values than 12.8 iirc
 
1) voltage sag is sorta a percentage and is not linear. So you have more buffer against loaded sag.
2) It is not unusual for new lead acid batteries in good condition to ‘store’ above 12.8V. Mine are over 13 with no input somewhat often. Lifepo also have higher static values than 12.8 iirc
Thank you, I will just live with it because at the end of the day, I still transfer over to grid once the voltage drops below 12.3 volts, but if it never transfers over to grid then who am I to complain? I more curious about why and your answer pretty much clocks it.
 
You can go lower than that without much effect - as long as they get volt-punched hard regularly and don’t go low on electrolyte they (lead acid) will or should last pretty good
How about dragging it down so low that the inverter screams and turns off? I mean when I curb stomp a battery, I don't half step. Still, I am loving the added battery and panel. Come winter I am really going to put the system to the test. But for the moment I am enjoying historically low energy cost at home. I should screen shot my utility usage.
 
Just to show you folks how much energy solar can save you, I have attached screen shots of where the savings really kicked in. Ironically it's not the electrical savings, it's the gas savings. By shutting down my central heating, the savings have been tremendous. Electricity usage has improved keeping on par beating similar homes and not quite as good as efficient homes but the gas savings is off the charts.
 

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How about dragging it down so low that the inverter screams and turns off
Sarcasm accepted :)
That is one way to need to replace your lead acid batteries every year!

I haven’t had my inverter go off on overload/low voltage since I replaced the 9-year-old batteries with new ones.
 
Sarcasm accepted :)
That is one way to need to replace your lead acid batteries every year!

I haven’t had my inverter go off on overload/low voltage since I replaced the 9-year-old batteries with new ones.
Now that I have the transfer switch running, the problem with batteries going Chernobyl is all but gone. I will need to come up with a way to use more than a heating pad. The heating pad is great for the wife because it's August and while Monterey still gets cold at night here, when winter comes we may still have comparably mild weather, rarely reaching 32 degrees (0 C) it will get cold enough that I will have to come up with heating solution to at least make the living parts of the house comfortable. But looking at the utility usage, I am still better off heating wherever I need the heat rather than depending on a central heating system that heats the whole house whether there are people there or not. Thanks for taking my humorous snarks with a grain of salt. September is the hottest month of the year here so I still have time to figure things out If you look at the averages here, the challenge is not out of reach:

January 61° / 45°

February 62° / 46°

March 63° / 47°

April 64° / 47°

May 65° / 49°

June 67° / 51°

July 69° / 54°

August 70° / 54°

September 72° / 54°

October 71° / 52°

November 66° / 48°

December 61° / 45°
 
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