# Our Planned Prioritized Solar Standby System



## Viking (Mar 16, 2009)

I had talked about what I have in mind for a standby solar system before but I thought I'd diagram it. The only other thing I may do is run a 120 VAC line to the washing machine as it is very efficient and not a power hog like the old one was. The refrigerator loads are 7.1 amps and 6.5, the freezer is 5 amps. The kitchen lighting circuit running all four lights is only 28 watts (four 40 watt equivalent LED's). Figuring that refrigerator/ freezer cycles run about 1/3 of a 24 hour day this system should have a good reserve capability. Thing is, if I set up a 24 volt DC generator system I probably wouldn't need to run the noisy, high rpm 120/240 VAC generator that goes through nearly a gallon per hour.


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## cowboyhermit (Nov 10, 2012)

Looks like you will have a nice setup.
Just curious on the details of the diagram, it shows you are feeding the inverter/charger grid power through the transfer switch. I am guessing that you would have the inverter/charger directly connected to the grid if using the charging capability, then usually the inverter would feed into the transfer switch parallel to the generator feed and the subpanel would be fed from the transfer switch.
Could just be a different setup, or a different way of drawing so I am curious.


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## Tirediron (Jul 12, 2010)

Couple of things to think on. Is pure sine good power for motors ?? semms to me that I read somewhere that they don't like it. and Are you always going to run the priority loads through the inverter/ charger ?? Not criticizing just asking. IF you could isolate the grounds, you could run 2 12v alternators for back up.


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## cowboyhermit (Nov 10, 2012)

Not to speak for Viking, but "pure sine wave" inverters are good for everything, including motors, the only drawback is the price. They aren't actually sine wave like a generator will output but they are close enough to feed into the grid (if so equipped)


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## Viking (Mar 16, 2009)

cowboyhermit said:


> Looks like you will have a nice setup.
> Just curious on the details of the diagram, it shows you are feeding the inverter/charger grid power through the transfer switch. I am guessing that you would have the inverter/charger directly connected to the grid if using the charging capability, then usually the inverter would feed into the transfer switch parallel to the generator feed and the subpanel would be fed from the transfer switch.
> Could just be a different setup, or a different way of drawing so I am curious.


The inverter has 120/240 VAC pass through relay. Hooked to grid the charger can be turned on by the control panel if due to bad weather solar doesn't keep the batteries topped off. If grid power is lost the inverter can be set to automatically take over separating itself from the grid by opening the pass trough relay.


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## LincTex (Apr 1, 2011)

Tirediron said:


> IF you could isolate the grounds, you could run 2 12v alternators for back up.


I doubt the regulators would like that. I would run the three internal phases to external rectifiers, then use one Balmar regulator to supply one output voltage to both rotors at the same time. Otherwise, you will get an oscillating load and they will start to fight each other.


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## Sentry18 (Aug 5, 2012)

Mental note: find one of these guys to join my group after (or before) the collapse because reading this thread was like reading Chinese. You provide the electrical engineering, I will provide copious amount of guns & ammo.


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## cowboyhermit (Nov 10, 2012)

A quite a bit of old machinery was 24V, we converted some and I think the alternators got scrapped, they probably weren't particularly efficient anyways but they would work I suppose.

I see how you intended the diagram now, internal bypass on the inverter, transfer switch only for the gen set. Looks good


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## helicopter5472 (Feb 25, 2013)

Could look in the military surplus most all the trucks are 24V. (80's pickups and Blazers) get a alt off one use it with small gas/diesel engine, I believe Coleman's Surplus even has 24V "starter generators" around 595 bucks, puts out 102 amps constant, if you are just charging you batt. bank


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## Tirediron (Jul 12, 2010)

LincTex said:


> I doubt the regulators would like that. I would run the three internal phases to external rectifiers, then use one Balmar regulator to supply one output voltage to both rotors at the same time. Otherwise, you will get an oscillating load and they will start to fight each other.


I kind of left that idea half finished,(I tend to do that) if you tried to run them in series they would probably oscillate and blow each other and the banks up, I was thinking more of a parallel circuit where each alternator would charge one 12V cell group. that way each alternator wouldn't see the other. like when you boost a 24v machine with 2 12v pickups. This is my usual what ever you can salvage design program. Hillbilly engineering aside I am liking this prioritized circuit system


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## mojo4 (Feb 19, 2012)

Sentry18 said:


> Mental note: find one of these guys to join my group after (or before) the collapse because reading this thread was like reading Chinese. You provide the electrical engineering, I will provide copious amount of guns & ammo.


Totally agree!! Math/electrical nerds do have uses after all. Guess I better start calling people and apoligizing for wedgies. My bad.


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## Viking (Mar 16, 2009)

helicopter5472 said:


> Could look in the military surplus most all the trucks are 24V. (80's pickups and Blazers) get a alt off one use it with small gas/diesel engine, I believe Coleman's Surplus even has 24V "starter generators" around 595 bucks, puts out 102 amps constant, if you are just charging you batt. bank


This is what I've been thinking about, a friend of mine is a generator expert and he gets a hold of mil surplus and a lot of older stuff and upgrades the regulators and governors, it seems to me I remember him mentioning that some of the older units had field exciter generators on front of the main generator that were 24 volts and could be pulled for other use. When I was in the Air Force 1961-1965 I remember that a lot of the equipment was 24 volt. By the way I'm no expert, just had a lot of years working with electronics and electricity, I also worked for Square "D" Electrical Company for nearly eight years where I assembled motor control circuits and built high voltage high amperage control systems (up to 6,000 amp buss work using three 1/4" X 6" solid copper buss per phase.) As to being a electrical nerd, well Nicola Tesla is really the hero of modern electrical systems, he invented motors, generators and the three phase electrical system we use today. He was also working on a system to send electricity to people without the use of wires, I think the Tesla coil was to be used. Anyway I guess that I'm somewhat of a nerd believing Tesla was a far better inventor that Edison.


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## cowboyhermit (Nov 10, 2012)

Lol, nobody ever attempted a wedgie on me, luckily for all involved
I may have intervened to prevent a few wedgie related altercations but some things are better left unsaid
If you are a big guy, plus one who farms, certain people assume you are lacking in intelligence. If you read a lot and have a bit of a mad scientist streak people assume you can't do a lot physically :dunno:


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## helicopter5472 (Feb 25, 2013)

I guess if you are both, your no one to mess with then...


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## Tirediron (Jul 12, 2010)

I am a fairly big guy too, a couple of kids went to the infirmary in school for taking a dare to try to give me a wedgie. A friend of mine is mensa smart or better and he is about 6'4'' and an easy 300#, he is also a rancher , he was born with a deformed palet (roof of his mouth) and had trouble talking clearly so people thought he was dumb, his distant cousin worked for Nasa and was know to call for advice.


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## cowboyhermit (Nov 10, 2012)

helicopter5472 said:


> I guess if you are both, your no one to mess with then...


I usually think of it as me being a bit of an outsider in both(all) groups but your way of putting it sounds better

The degree to which people judge by appearances can be surprising, can't say it has been much of a detriment to me but I have seen it with others.

Viking, I agree Tesla was a great inventor but I do kinda wish we had ended up with a DC grid, of course AC has tons of benefits I just like DC. Didn't mean to go off topic I hope you give us updates if you make progress on your system, looks great IMO.


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## LincTex (Apr 1, 2011)

OK, back on topic.

You don't need a 24 volt label on the alternator you use, just add more volts to the rotor windings, that's all. 

A regular 12 volt alternator will put out over 120 volts if you feed the full 12 volts into the rotor and spin it fast enough. Ever see those gizmos under the hood of old trucks with a toggle switch and a 120volt outlet? A lot of old farmers had them in the 60's and 70's. They would use their truck alternator to run an electric drill or hand grinder out in the field to get their combine/swather/sickle mower/etc. going again. 

The problem with the "gizmo" is it only works with brushed motors... Which is fine for farmers, and most drills and grinders are. The power coming out of the outlet is DC at 105-130 volts (truck needs a hand throttle) and the frequency is anywhere from 100-500 Hz depending on alternator design and speed.


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## LincTex (Apr 1, 2011)

Some really informative stuff related to this topic:

http://www.otherpower.com/images/scimages/1431/Alternator_Secrets.pdf

http://www.microcogen.info/index.php?topic=2111.0
[quote author=Ronmar link=topic=2111.msg28130#msg28130 date=1323788818]
Well if you read thru Bobs White paper on alternator efficiency, the quick and dirty way would appear to connect the alternator output across your 24V string, but connect it's regulator sample input across 12V of the 24V bank. The regulator will adjust the output which is fed across the 24V bank, to reach it's desired 12V level as measured in the middle of the bank. IE: It will drive the output to 24V to get 12V in the middle where it is sampling. You do need to provide a 12V source to power the alternator field though...
[/quote]
http://www.microcogen.info/index.php?topic=1748.0

http://www.microcogen.info/index.php?topic=2228.0

http://www.microcogen.info/index.php?topic=2912.0

http://www.microcogen.info/index.php?topic=2941.0


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## Viking (Mar 16, 2009)

LincTex said:


> OK, back on topic.
> 
> You don't need a 24 volt label on the alternator you use, just add more volts to the rotor windings, that's all.
> 
> A regular 12 volt alternator will put out over 120 volts if you feed the full 12 volts into the rotor and spin it fast enough. Ever see those gizmos under the hood of old trucks with a toggle switch and a 120volt outlet? A lot of old farmers had them in the 60's and 70's.


Now that you bring this up, I just happen to have one of these "gizmos" that a friend gave me that's never been used. I've not really needed it so far probably due to the advent of cordless tools so readily available.


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## Kenny78 (Jul 12, 2011)

Hey Viking, is your generator an exciter cranked unit, like an onan. If so alot of dc juice can be pulled off of many onans at a surprising voltage. I realize that means running your gen but not changing ac to dc might bring an eficiency bump. 

As to tesla, if he had been supported instead of destroyed, I think we would be living in a different world today. Though I admit that had Wardencliffe been successful it would put menout of a job


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## LincTex (Apr 1, 2011)

Viking said:


> I've not really needed it so far probably due to the advent of cordless tools so readily available.


They won't work with an internally regulated alternator; external regulator only. When GM switched their 10si from ext to internal, this device concept became doomed (lots of farmers drive Chevys).


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## Tirediron (Jul 12, 2010)

Linctex, what does the device do, short the field? , I have an old service truck with a 10 si, I hooked a wire to the regulator override tab screw and then ran it to a rotary switch, so that I could selectively "bump" the field with the resistance of a light bulb.


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## LincTex (Apr 1, 2011)

Tirediron said:


> Linctex, what does the device do, short the field?


It bypasses the regulator... sends full 12volts to the rotor. Output voltage and speed are then dependent on engine RPM. Because the diodes are not bypassed the output is DC, which works fine for brushed AC motors in drills and grinders.

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

http://www.otherpower.com/images/scimages/1431/Alternator_Secrets.pdf










If you open the alternator and access the windings, you can get AC power but it still won't be 60Hz.


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## Tex (Oct 31, 2008)

Does your inverter turn on automatically when your batteries are completely charged? If not, what keeps your batteries from overcharging from the solar panels? I'd use the excess power for pumping water, since it is needed anyway.  Some people just burn it off with lights.


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## LincTex (Apr 1, 2011)

Tex said:


> Q: What keeps your batteries from overcharging from the solar panels?


A: a good quality charge controller.


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## Viking (Mar 16, 2009)

LincTex said:


> A: a good quality charge controller.


The charge controller I got for the system is Morningstar TriStar 60 it does what's called Maximum Power Point Tracking and it can boost the charge current under certain conditions by using the excess voltage developed by the panels into increased charging amperage. The maximum voltage my solar panels will put into the controller is 36, the batteries and inverter are 24 volt so even on a day that it's cloudy or hazy the panels potentially can put out enough voltage to bring the batteries up to charge. Of course I could series the eight panels in twos which would bring the volt up to a total of 72 which might enhance charging even more on low solar panel output days but from experience in having a like system on our motorhome it will do well with the 36 volt array. The panels on the motorhome are 44 cell and put out over 20 volts in full sun and so even on low output days the panels usually produce over the 14 volts needed to charge the house batteries, the controller for these panels is a 30 amp MPPT. The great thing about MPPT controllers is that they automatically go through charge sequences Absorption, Float and Equalize, the Equalize stage can be set for a set number of days between equalizing according to battery type needs. The equalizing stage allows for a short time period of higher than normal voltage to clear off cell surface build ups that reduce battery efficiency and shorten their useful life span.:tmi:?


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## Tirediron (Jul 12, 2010)

Viking there is no such thing as too much info, especially solar power info, 'cause a lot of times it is guessing or sales hype when first starting a system.


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## Viking (Mar 16, 2009)

Well I finally got my batteries up to the solar/tool shed, now begins the wiring. The neighbor that does metal salvaging gave me a bunch of welding cable which I will use for battery connectors, I make my own terminal ends with copper tubing. For wiring to the inverter/charger I'm going to have to get some larger wire from batteries to it. I'll have to bury Electrical PVC conduit from the shed to the house for 120/240 AC and to were the solar panels will be mounted. As always, more work to be done than money for the things needed to get this project done, but we'll get there eventually. At least I have a generator to take care of any winter outages in the meanwhile.


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## cowboyhermit (Nov 10, 2012)

Nice! Have you tried the copper tubing connector thing before? Do you plan to solder them?

The price of simple little components does annoy me at times. I don't mind so much if it is something like an Anderson connector that is ridiculously expensive, but something as basic as a copper end can be a pain.


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## Viking (Mar 16, 2009)

cowboyhermit said:


> Nice! Have you tried the copper tubing connector thing before? Do you plan to solder them?
> 
> The price of simple little components does annoy me at times. I don't mind so much if it is something like an Anderson connector that is ridiculously expensive, but something as basic as a copper end can be a pain.


Yes, I made the connectors for the motor home solar system using copper tubing and it can be a PITA. I flatten the connection area, drill the mounting holes and then soldier the wire in, I also tin the flat area to make sure they don't corrode from acid vapors due to charging. As to using manufactured connectors, I'll have to talk to my friend that works on all kinds of generators, I'm sure he may have some suggestions for connectors and access to a high pressure crimping tool. He's the one I will probably get heavier gauge wire from for connecting the battery bank to the inverter.


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## squerly (Aug 17, 2012)

Hadn't thought of the copper tubing idea but I have to wonder, is all that work worth it?


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## Viking (Mar 16, 2009)

squerly said:


> Hadn't thought of the copper tubing idea but I have to wonder, is all that work worth it?


Yes it's worth it if you don't have easy access to a terminal crimping tool or the terminal ends. I've never checked a rental shop to see if they have the crimp tool but there isn't too many people that work on high amperage connectors around and the people that advertise making automotive cables aren't even close to where I live though when I'm in town next time I may check some places out like Interstate Battery Co.


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## cowboyhermit (Nov 10, 2012)

Crimped ends are supposedly better in all regards, wire doesn't get stiffened, stronger under high temps, etc. But, I have had really good luck with soldered ends over the years especially with corrosion, heck sometimes I even solder crimped ends 

The ends are pretty widely available around here in a few varieties, they make some heavy duty connectors that you just hammer down (they have a lug and are designed for it), they work good but tend to be bulky and $$$. They also make some pretty simple and affordable little crimpers that you hit with a hammer, about as good results as any press, even if it is counter-intuitive (I tend to think an even pressure would be best). Then of course the simple copper ring terminals are the cheapest and I have found pretty darn reliable with good soldering or crimping. Really big ones are still only like $1 each, but I do like the idea of copper tubing, certainly a good option in a pinch.

Other than welders, another good place to look is after market stereo (other modification) places, they use ridiculously heavy wires often and are particular about good connections.


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