Low battery automatic transfer inverter (PROBLEM SOLVED)

fblevins1

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Wile E Coyote, Super Genius 😉

Easy way to cancel the refund is to forget sending the old one back
Unfortunately they were going to send me a new unit and if I did not return the old unit by Sept 22 they would charge me another 119 bucks, but....I got in a chat session with Amazon and they cancelled the return so I am good to go now. The new battery and solar panel just arrived in the mail so I am a go for setting my system up. Just stopped by Ace and picked up a bore bit to widen the existing hole in the side of my house. The owner does not want me drilling new holes but he was good with me making use of an old cable TV hole that was already there and not being used, and the location is perfect, it is where I want my panels and within two feet from an AC outlet and I can hide the entire set up behind the kitchen table that is butted up against the wall. This is going to be great.
 

fblevins1

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Well, it's done. I now have a semi-permanent, 3 100 watt panel, 2 100 Amp Hour AGM battery set up with inverter and transfer switch going that in theory I should not have to touch for a very long time. The table leg caused some logistic problems as I had to move both the inverter and transfer switch further away from the battery box than I wanted so I had to use longer wires to make the connections but in the end the wires were heavier gauge and hard mounted rather than just clipped on, which I think produced a better end product and probably safer. The only thing I have left to do is make a wood frame for the 3 panels. Right now they are just laying in the back yard. I will probably make the frame tomorrow. I tell you what, adding the second set of panel wire splitters was like a puzzle at first, I was like WTF sort of madness is this? But rather than try to add the two new splitters to the old, I took it all apart and added the splitters and got it all set up right. When it is all complete I will snap some pictures and upload them on here. Nothing to write home about, but is my first semi-permanent solar set up.
 

wiseacre

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I too plan on making a frame tomorrow. I was going to extend my current frame to add two more panels but decided to build a "movable" platform so I can better catch some winter sun. The current array is fine for summer but gets shadowed by the house during "prime time" in winter, by the time the sun hits them the day is almost over. Once I figure out the best location I'll build a permanent array with adding more panels in mind. Both set of frames are/will be adjustable for best summer/winter angles, I doubt it makes much difference but I like to squeeze as much out of my panels as possible.

I'll take some pics too. It will be interesting comparing our small frame builds.
 

pollenface

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If you have mains power available you can set the low voltage disconnect/reconnect settings on your SCC to switch a couple of relays to turn on a charger for your battery bank at your desired voltages. Transfer switches usually incur a small power interruption, but staying on inverter power can mitigate that if interruptions are undesirable.

My Epever 4210AN is configured to do as such and the mains wires go through 2x relays so the charger is not powered on when on standby.
 
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fblevins1

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I too plan on making a frame tomorrow. I was going to extend my current frame to add two more panels but decided to build a "movable" platform so I can better catch some winter sun. The current array is fine for summer but gets shadowed by the house during "prime time" in winter, by the time the sun hits them the day is almost over. Once I figure out the best location I'll build a permanent array with adding more panels in mind. Both set of frames are/will be adjustable for best summer/winter angles, I doubt it makes much difference but I like to squeeze as much out of my panels as possible.

I'll take some pics too. It will be interesting comparing our small frame builds.
Mine will be a simple wood frame big enough to hold the 3 panels. It will either lay flat on the ground or tilted towards the sun via either attached legs or by simply using a metal folding chair that happens to be in the back yard. I was able to find a good location that gets early morning sun and late afternoon sun, probably the only place in the yard that does. And that location just happens to be right where the pre-existing old cable TV wire hole that was drilled into the home and just on the other side of that wall is the set up. I might paint the frame to help keep it from warping due to moisture or whatever. I am still sorting through the adjustment mount in my mind. When I go to home depot I will see what hardware jumps out at me and forces me to buy it. I am also considering using a piece of weather resistant ply wood, but I am concerned about heat build up for the one flex panel. On a side note, has anyone ever considered using large mirrors to increase the amount of sun that gets to a panel? Just a thought.
 
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sunshine

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On a side note, has anyone ever considered using large mirrors to increase the amount of sun that gets to a panel?
There were large installations built using mirrors. Nowadays a mirror is probably more expensive than PV!
No reason not to place your panels in a position were they get reflective light off opposite wall etc if there is no other reason not to!

The cheapest frame I've used ( other than just hanging them vertical off the fence) are from old swingsets with 2 horizontal C channels from the tip.
 

fblevins1

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There were large installations built using mirrors. Nowadays a mirror is probably more expensive than PV!
No reason not to place your panels in a position were they get reflective light off opposite wall etc if there is no other reasons not to!

The cheapest frame I've used ( other than just hanging them vertical off the fence) are from old swingsets with 2 horizontal channels from the tip.
Good point. My thought were more of a if you have an extra mirror laying around, put to work. I will probably do at test with a tall mirror that is just standing in the hallway just to see if extra sunlight actually makes a difference, more of a let's see thing. Like you said, depending on what you have available the sky is the limit. I like that though, use a swing set or lean it up against a fence. Here the fence is more of a block than help although I do have long enough cables attached to make one of the fences a good morning tilt location. Food for thought...thank you.
 

sunshine

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Food for thought.
For a solution to your earlier problem, and the one I use, rather than a ATS is a mains/dc psu (240v/12v here) just left on 24/7 connected to the battery. It must be larger than your expected power use (not peak just normal) and with diodes for protection when the pv is higher,
A PC PSU will suffice, however its V and with the added diodes is slightly below 12v, My ideal is 12.6v for lead acid. I've had to keep changing and adding psu's as the system gets bigger and am waiting on the arrival of a 1500w variable supply unit from China that is also suitable for a change over to LiFePO4.

You need to do some creative thinking to account for the loss from 240v-12v-240v and running 24/7. The standby current is very low and they are only outputting when the v is below theirs.
 

fblevins1

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For a solution to your earlier problem, and the one I use, rather than a ATS is a mains/dc psu (240v/12v here) just left on 24/7 connected to the battery. It must be larger than your expected power use (not peak just normal) and with diodes for protection when the pv is higher,
A PC PSU will suffice, however its V and with the added diodes is slightly below 12v, My ideal is 12.6v for lead acid. I've had to keep changing and adding psu's as the system gets bigger and am waiting on the arrival of a 1500w variable supply unit from China that is also suitable for a change over to LiFePO4.

You need to do some creative thinking to account for the loss from 240v-12v-240v and running 24/7. The standby current is very low and they are only outputting when the v is below theirs.
It could be that I am drinking some port wine at the moment, but that went so far over my head that I am sure it hit an airplane flying over the house. Did you just say that using a PC (computer) PSU will do what to who? I really have to lay off the hooch.
 

sunshine

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using a PC (computer) PSU will do what to who? I really have to lay off the hooch.
Yes. Converting old pc psu's for 12v power been around far longer than the how-to's on youtube.
Just remember watts are watts! So you need to match that for input to output.

Daytime is ok, battery and pv covers the power use. At night only what is under the psu output is left on.
 

fblevins1

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Yes. Converting old pc psu's for 12v power been around far longer than the how-to's on youtube.
Just remember watts are watts! So you need to match that for input to output.

Daytime is ok, battery and pv covers the power use. At night only what is under the psu output is left on.
This might sound crazy but I think I understand what you are talking about. That would have been preferable to simply putting a smart charger into the mix. If I understand what you are talking about, the PC PSU would not do much as long as the battery voltage was greater than the PSU but...once the battery reached or fell below the PSU out voltage, it would start producing enough power to keep the appliance running while maintaining the battery charge enough to keep it from going critical. I am drunk as a skunk but am I even close? It's also good to know that when the unit is not actually producing power, the insertion loss is not that great.
 

fblevins1

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Update, I woke up this morning and the system voltage was 13.1 and the wife had her phone charging and the heating pad running. No sign that the transfer switch ever needed to use grid. I got out my thermometer and took a reference temperature of the room it was installed @ 71 degrees. I checked the wires, batteries, TS, inverter and the solar charge controller and the highest temperature recorded was on the charge controller @ 75 degrees, with the wires being at the room temperature so I think I have it all properly gauged. Going to attempt to make the frame today but that depends if my truck buddy can get the time today. Home depot will do the cuts for me free. Good morning west coasters and good whenever for the rest of the world.
 

12VoltInstalls

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twice the battery power and 4 panels backing them up.
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.
 

12VoltInstalls

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voltage was 13.1 and the wife had her phone charging and the heating pad running. No sign that the transfer switch ever needed to use grid.
That’s great! Using the bonus power well.

twice the battery power and 4 panels backing them up.
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?)
because I have inverters, so for that price, I am going to buy one because I have everything else I need to make a working system no matter what.
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.
 
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fblevins1

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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.
The inverter is a cheap 1000 watt unit with fan cooling. I do have a super whamydyne 5000 watt inverter with blue tooth control but the insertion loss is much more and the extra wattage is not needed. I am only needing up to 140 watts of power, but that allowed me to unplug the huge central heating unit and that is where the savings are coming from. My baseline power usage for gas went from being the worse in the neighborhood to being more energy efficient than nearby "efficient homes" and significantly better than similar homes. Electric usage is lower than similar and near the efficient homes level.

Turns out I only have 3 Panels running because the 4th panel my son bought me was a small panel with built in USB brick so that's nice but not part of the grid. I think 3 will sustain my batteries, maybe when I make the panel frame I should leave an extra panel slot space so I can add another panel later? I don't know if my inverter is a pure sign wave output but I could pop a scope on it and see, although from my measurement point of view, even the so called pure sign wave outputs would still look like crap to me. Also I think most of the appliances I am using could care less although the better the inverter the better the efficiency....maybe. I forget what the unit of measure is for power efficiency. My back up plan for an actual power outage is get the 5000 watt inverter out hook it up to my car and use the car as a generator to keep us going until the power comes back on. My refrigerator spec says it only needs 750 watts peak, but empirically that's a load of crap, my 1000 watt inverter pitched a hissy fit when the compressor kicked in.

As my knowledge base increases, I will probably upgrade components along the way and off course technology is getting better too.

Thanks for chiming in, I got a lot out of your comment and more food for thought. I think my brain is gaining weight. Edit: I guess power quality or power factor is the term I was looking for. I could bring in my Fluke power quality analyzer but I am happy with just using a AC/DC Clamp meter to figure out how much my inserted components are consuming. Generally I just use power in vs power out to figure that stuff out, not really putting too much though into all that. The problem is the fluke is not designed for DC although (don't tell Fluke this) the clamps really DC responding too, but the unit of measurement is still in Amps RMS and Volts RMS, I just have to know I am measuring DC which I think DC is the RMS equivalent....maybe.
 
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12VoltInstalls

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I don't know if my inverter is a pure sign wave output but I could pop a scope on it and see, although from my measurement point of view, even the so called pure sign wave outputs would still look like crap to me. Also I think most of the appliances I am using could care less
Actually there are ‘true sine’ inverters that are cleaner than the grid sometimes and often better than gas generator outputs.
If the inverter was $50-$100US it’s probably modified sine; $165+ maybe true sine , $189-$1000?! it is very likely a true sine.

The heat blanket and usb outlet could’nt care less, but many/most other items will care about pure sine. I ‘knew’ this but yet I killed many more dollars than a pure sine inverter cost with mod sine inverters before I stopped being stupid. Sometimes a plug-in charger will work with mod-sine, others it could kill. Just an FYI
 

DerpsyDoodler

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If you have mains power available you can set the low voltage disconnect/reconnect settings on your SCC to switch a couple of relays to turn on a charger for your battery bank at your desired voltages. Transfer switches usually incur a small power interruption, but staying on inverter power can mitigate that if interruptions are undesirable.

My Epever 4210AN is configured to do as such and the mains wires go through 2x relays so the charger is not powered on when on standby.
You'd probably be better off putting the relays on the feed from the solar panel to the controller (rather than battery to controller).
 

fblevins1

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Actually there are ‘true sine’ inverters that are cleaner than the grid sometimes and often better than gas generator outputs.
If the inverter was $50-$100US it’s probably modified sine; $165+ maybe true sine , $189-$1000?! it is very likely a true sine.

The heat blanket and usb outlet could’nt care less, but many/most other items will care about pure sine. I ‘knew’ this but yet I killed many more dollars than a pure sine inverter cost with mod sine inverters before I stopped being stupid. Sometimes a plug-in charger will work with mod-sine, others it could kill. Just an FYI.

Most of my intended appliances probably won't care and the few that converts AC to DC probably can be OK, just simple converter bricks. Not sure If I would want to run a PC on a crap inverter. I will eventually purchase a super whamydyne inverter but for the moment the best I can do is use the grid to establish what a good baseline for power quality is and just be happy if I can hang with that.
 
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