Home made solar inverter generator.

oil pan 4

I would like to take my little generator rig and add one or two 100 watt solar panels and charge controller to it.
The solar panels I have seen measure about 47 x 21 inches and make 100 watts each. At the very least I would like to attach 1 solar panel over the fuel tank, that will provide inverter power and keep the sun off the fuel tanks and inverter. The second solar panel if I decide to add one will just simply be staked to the ground next to the generator.
I already have the AGM battery and KISAE pure sine inverter as you can see.
The AGM battery was free and when it dies I will replace it with something larger and more deep cycle friendly.

I know this isn't a real "inverter generator" like what Honda makes, I know what those are, I work on them. But mine has a few huge advantages over the traditional inverter generators, I can get some power with out running the engine and I will have a solar panel.
This will help off set its catastrophic fuel consumption of .77gal/hr at half load and a half gallon to 2/3 gallon per hour at no load to light load.
The inverter will power small stuff like USB chargers, run drills, charge batteries, run small saws, run my small 1hp air compressor for intermittent nail gun use, maybe run a refrigerator.


The solar panel will be stowed on the side of the generator during storage, lifting and transporting and removed before starting.


That leaves one thing.
The charge controller. The solar panels I was looking at have an operating voltage of 19 volts and put out 5 amps.
It looks like most charge controllers want you to run the solar, battery and inverter off the charge controller, in effect making the charge controller the center piece of the operation.
I only need something that will keep the solar panels, which can build a max open current charge of 22 volts from frying the battery. The Kaise inverter will auto shut off if the battery gets below 10.5 volts and I have a 100 amp DC breaker going to the inverter.
It looks like I should be able to just hook up a standard 20 amp charge controller and hook it up to use only as a battery charger. This inverter will need around 80 to 90 amps at full power so running it through one of these 20 amp charge controllers isn't going to work with the inverter running any where near full power.
I also wouldn't mind having a charge controller with a high voltage AC input option so I don't have to drag a conventional battery charger around with me if I need to charge the battery with the generator say at night or on a cloudy day.
Any one have an idea as to kind of charge controller I might be looking for?

BB.

I am not quite sure what you are trying to do here... Obviously a few hundred watts of solar panel is not going to compare with a 7+ kWatt AC genset. And mounting panels+charge controller to the genset is a vibration/heat problem waiting to happen.

If you break this into two to three components... A Magnum AC inverter-charfger + AC transfer switch + battery bank + Solar Charge Controller (sized to array) is one. The second would be the genset (plugs into the AC inverter-charger--Engine running, inverter passes power from the engine to the loads, and charges the battery bank). The third, your solar array/kit.

That way, you can move the right gear to the right job...

-Bill

oil pan 4

Yes I should have been more clear on what the scope of this rig is.
I guess the easiest way is to break it down into 2 parts.

The main part is the generator. Its just a 7kw generator. That's all its ever going to be is a single phase 2 pole, 240 volt bonded neutral generator that screams along at 3600RPM guzzling down at least a half gallon of fuel per hour. The generator will be used to provide power directly to larger items that would kill the battery, exceed the output of the inverter or require 240 volt power. Items such as small and medium welding machines, my 2003 vintage miller 625 spectrum plasma cutter, multiple air compressors, air conditioners, large saws, metal chop saw, refrigerators/freezer or providing power at night and charging the battery for use powering tiny items at night.
*note, to power the miller 625 a separate 5 horsepower gasoline air compressor provides the air. To run the miller 625 at full power it takes every bit of power this 7kw can make, nothing else can be ran when the miller is turned all the way up.
Also the 230 amp welder typically is ran at around 120 amps, which is the max power this generator can put out.

The second part, the solar panel, inverter and battery are pretty much just additions, almost a completely separate systems all together. That is all I ever want them to be.
The only link between the solar/inverter and the generator is the battery.
The battery is the starting battery for the generator and it also powers the inverter, the battery is also charged by the generators flywheel magneto. But the flywheel magneto is only designed to replenish a small riding lawn mower sized battery after cranking the engine. To make sure the battery gets fully charged I will continue to use some kind of additional battery charger.

Technically this rig is a hybrid.

The back story to the current additional equipment:
The larger battery was installed because it was free and the OEM lawn mower style battery it originally had was flat dead.
I bought that inverter used off ebay. More like I stole it. I knew I needed a pure sine wave inverter to run battery chargers, so I didn't even waste time screwing around with that cheap "modified sine wave" garbage. Since it was a used inverter, up for auction, I put in a bid and I was the only one to bid on it. The only decent looking pure sine wave inverters I could find just happened to be 900 watts and up, this is a 1000w.
The inverter was added to power tiny or intermittent loads such as a small 3/8 drill, USB charger, laptop, dewalt battery chargers, stuff like that and not all at once, since the battery had no incoming charge.

Well it turns out I really like using the battery and inverter when ever possible and just want to expand its role. If the battery and inverter could continuously have 5 or 10 amps going to it while the sun is out that would allow the inverter to do a lot more, meaning the generator will stay off a lot more.
With 10 amps going to the battery continuously it could easily keep a small refrigerator cold while the sun it up. (not plug in a warm refrigerator and bring it down to temperature, would still need to run the generator for that initial cool down, or install much larger deep cycle battery)
Or it could easily power my little 1hp air compressor to run a framing nail gun or finish nailer intermittently. As of now I only use it once or twice to build up my little blue 1hp compressor to fill a tire or something small like that.
Or it could power all the tiny intermittent items with out worrying about the battery quickly running out of power while the sun it up.
Or I could intermittently use a sawsall or portable band saw.
I could power something else off the inverter while the plasma cutter or larger welding machine were using all the generator's power.

Realistically I am only expecting to get about 5 amps out of each "12volt 100watt solar panel".
I would get 150 watt panels (8 amps each!!! the solution to all the worlds energy needs) but I think the 150 watt panels are just too big. If I take some measurements and find panels with the cells rows stacked just right it might work.
But I went big on the inverter and I am not regretting it, I will go big on the panels too if I can.

It looks like the main problem is generator vibrations effecting the attached solar panel. Would rubber shock mounts between the brackets and mounting points be enough or should I just forget about running the generator with a solar panel on it and just attach the panels to something that doesn't vibrate or build portable racks to stake them to the ground?

I only need a solar charge controller that can handle 20 amps. If there were a double duty charger that could take solar panel power by day and gen set power by night or as needed that would be ok too as long as it were not super expensive.
I would like the double duty solar and gen set powered battery charger to be able to put out at least 20 amps when its on generator power, if such a thing exists?

Or as a 3rd option, make a power supply to feed power to the charge controller in place of the solar panels. Some where in my junk collection I have a large 24 volt 350VA power supply transformer. It has multiple voltage input taps from 240 to 480 VAC. I could apply 240VAC power to the 380VAC input taps (stepped down about 15:1) that would give me some where between 15 volts RMS and 21 volts peak sine volts wave after I rectify it and add electrolytic capacitors, ultimately giving me that funky "12 volt solar panel" operational voltage that seems to always seems to fall between 17 and 21 volts DC.
This transformer should only provide about 14 or 15 amps of output.
I have all the little parts to do this left over from my welding machine DC conversion and upgrade projects, rectifiers, inductors, 100,000uf electrolytic caps poached from a dead battery chargers and so on.


Because after all, firing up a 7kw generator just to plug in a USB charger, run a tiny drill or charge a dewalt battery, or power a sawsall 10% of the time is kind of ridiculous, right?
Or even worse, firing up a 5 horsepower gasoline air compressor just to shoot a nail gun several times a minute. That is not ridiculous its a travesty.

BB.

Start with the loads--But if not that, start with the battery...

Lead Acid, AGM, LiFePO4?

Looking for high surge capacity vs weight--Li or AGM. Looking for "cheap" long term power (i.e., lights, cell chargers, power tool charging) then 6 volt 200 AH golf cart batteries are the way to go.

Use system "all the time"--Worth the maintenance of checking/adding water to flooded cell batteries.

Use system in emergencies--Then LiFePO4 or similar technology may be a better choice.

Want emergency power with little maintenance... Perhaps forget the batteries+inverter. An eu2000i or eu1000i Honda genset and 5-10 gallons of gasoline (with fuel stabilizer, rotate into car 1-2 times per year). Use 0.1 to 0.25 Gallons per Hour (eu2000i--1,600 Watt genset).

-Bill

oil pan 4

As of now the only thing I will run off the power inverter and battery now are the drills and various battery chargers. I have used it to build up my little blue air compressor, but that was mostly just to see if it could handle it.

The loads I would like to run off it are a refrigerator, small 1hp air compressor that only draw about 600 watts at shut off, 1/2 and 3/8 inch drills that draw up to 500 watts but only when going balls out, 4 and 5 inch flap wheel and wire wheels on angle grinders, portable band saw that draws up to 10 amps at full power but it has adjustable speed and I can ease the saw into the cut to reduce watt draw, maybe try running a skillsaw off it through a varrac at reduced voltage, this saw ran great on 100 volt 50Hz power when I first bought it in japan. My small 10 watt soldering pen which has its own mini varrac so I can reduce its power down to like 4 watts once its up to temperature.
I may want to run some 12 volt LED light, I figure I can run these straight into the charge controller's output.
Obviously I cant run all this. The power tools would be very intermittently used.

The only real battery killer would be powering a fridge. If I power the big fridge at home it uses up to 350 watts, a small camping fridge uses closer to 200 watts while its on. Last time I checked the home fridge it uses as little as 1.5kw per day, but can use up to 2.5 if people keep going in it or if it gets opened up and cleaned out.
The plan for running the fridge would be to put the thermostat on the lowest setting cool the fridge down with the generator while getting the battery all charged up, turn off the generator then turn the thermo stat back up to the normal range run it on the power inverter for a few hours, let it sit for a couple hours with no power. Fire up the generator, plug the fridge into the generator cool the fridge and its contents all the way back down to the thermostats lowest setting while charging up the battery, turn the generator off and repeat as needed.

I know I am not going to completely replace the generator for running all the small things. Just want to get a little more out of the power inverter and run the generator less.

The current battery is an AMG with only about 20 useable amp hours. I am thinking that when this battery goes bad I will replace it with a much bigger flooded lead deep cycle. I don't want LiFePO4 because they don't like to work when it gets much below freezing and I know that charging them if they are below +20'F can damage them.

I don't think I will be doing 200ah batteries, they would weigh over 140 pounds. I need this little rig to be some what portable. The optima battery has a normal weight of 44lb. I could go double that.
As it is now, with a full load of fuel and all its cords on there this gen set weighs about 350 pounds. I would kind of like to keep it around 500lb or less at full battle rattle.

This thing sits pretty much all winter unless the power goes out. Then gets dragged out to go camping and to go build stuff.

I did some measuring and it doesn't look like I will be getting 100 or 150 watt panels, I am going to stick with 80 watt panels. They are only about an amp less than the 100 watt panels but they will fit the portability standard I need a lot better. Since realistically I think I will only be able to get 4 to 4.5 amps out of them. I will go with at least 2 for sure.

oil pan 4

The only part I was unsure of was the charge controller I went ahead and picked up a Morningstar ProStar 30 amp charge controller.
People on here who have a Morningstar seem pretty satisfied with them.
I know its a little over kill but I could always expand the system.

Since I could not locate a charge controller with a built in high voltage battery charger I am building my own battery charger that runs off generator line to line voltage.
I have a good size 350VA, Made in USA squareD industrial control power supply transformer that I have had in my junk collection since 2007, if not earlier. I found when I apply 245VAC to the 380VAC input coils I get 16.3VAC on the secondarys. That should produce a maximum theoretical voltage of 23VDC if there were no losses in the rectifier and if the capacitor could capture and keep peak sine wave voltage. Under load it should be the same voltage as a "12 volt solar panel".
When I need a charge that the solar cant provide, just insert battery charger power in place of or in addition to PV through the charge controller.

I have already started building the 240 volt powered battery charger power supply. Its coming along very nicely.

oil pan 4

Here is the battery charger so far. Transformer, 100,000uf battery charging capacitor, 275v MOV, rectifiers on a heat sink and water proof external switch, single pole double throw switch. Each line will have a 3 amp fuse going to the transformer then a 20 amp automotive blade fuse coming off the transformer. Power is supplied to the box with some 16ga SJ cable. The battery charging power will be supplied by 10ga TH or TW wire to the charge controller.
Obviously nothing is hooked up yet.
Attachment not found.
Attachment not found.

oil pan 4

I installed the cord strain relief, double 3 amp fuse holder, loosely assembled the transformer, bridge rectifier and capacitor together then applied 245VAC to the 380VAC input terminals on my transformer and it produced 21.5 volts DC at open current, just like a "12 volt" solar panel.
Perfect so far.

oil pan 4

I didn't realize my red top optima battery had a reserve capacity of 100 minutes.
If I replace the red top with a blue or yellow top it goes up to 120 minutes.
Or I could install a die hard group 65 battery AGM and get 135 minutes of RC. (these weigh 60lb)
Since the optima deep cycles weighs 44lb and has a 120 minute RC and the group 65 AGM weighs about 33% more and only gives you 12% more minutes of RC, I am thinking optima is being overly optimistic or sears is derateing their batteries.
I am leaning towards upgrading to a group 65 AGM when the current optima dies.

Reserve capacity minutes describes my most on going load pretty well, powering a refrigerator which should use some where around 300 watts while its on.

I have two 80 watt panels on their way to me some where in the back of a fedex tractor trailer.

oil pan 4

My battery charger works great. It was pumping 26 amps through the Morningstar and into the battery and inverter when I tested it.

Solar panels came in, just waiting on more MC4 connectors.

I do believe I am going to pull the optima battery and put it in a vehicle, its replacement will likely be a sears diehard group 65 AGM.

oil pan 4

I pulled the optima battery for auto motive use, leaving my solar inverter hybrid without a battery.

So I went to sears and saw the group 65 battery, then saw the bigger group 31 that would not fit my battery space. So of course I bought a diehard group 31 marine AGM battery that I know does not fit, I am going to play a game called "make it fit with my plasma cutter" to get it in there.

It weighs 75lb, has 205 minute reserve capacity, which works out to about 85 amp hours, but if you slow the discharge rate down to 1C over 10 hours (about 9 amp load) the amp hour capacity goes up to 92 amp hours, if you use the 1C over 20 hours (5 amp load), you can count up to 100 amp hours coming out of the battery. (Peukert's law)

Not buying a quality AGM battery to put in the vehicle saved me $180 to $220 and I was able to find an excuse to buy the bigger battery for the solar inverter generator. 2 battery upgrades for the price of 1.

The sears diehard group 31M (marine) AGM battery was on sale for $278 (normal price is $309). Ironically I used the generators original long dead "riding lawn mower battery" for the core charge.

The flooded lead acid starting battery I pulled from the vehicle has some life left so I am keeping it around for now.

PNjunction

Glad you got things working!

You may be interested in the CTEK D250S Dual dc source autoswitching charger.  Mostly used by 4x4 guys that have solar and starting duties.

Quick note - you know that a Sears Diehard "Platinum" is a rebadged Enersys/Odyssey batt right?  Awesome if you need that pure-lead injection and no current limit as long as your CV is tight.  The "Advanced Gold" is a rebadged East Penn / Deka conventional agm, also a very good choice in the hybrid-cycle department.

oil pan 4

Yes I saw that odyssey makes the diehard AGMs.

The optima AGM held up well to the occasional use for over 2 years.

That dual DC charge controller is pretty cool, but I may need a good bit more than 20 amps for charging some times.

I have worked with mostly 34/78 optima batteries since 2003 so I know how much power the like to charge at. For an optima, red, blue, yellow. That 20 amp CTEK D250S dual charger would be perfect for optima 34/78, they naturally tend to like to draw about 20 amps unless they are pretty low.

This group 31 AGM is almost double the mass of the optima. I think it might try to over load the Morningstar drawing power from the solar panel in a box.

oil pan 4

Looks like some of my pics have been dumped off the server.

Here is my more updated post:

http://ecorenovator.org/forum/solar-power/4544-home-made-solar-inverter-generator-hybrid.html