Home made solar inverter generator hybrid

[oil pan 4]

This little thing gets use it all the time. I roll it out of the shed because its in the way and use it because its there, turn on the inverter, put the panel up, plug in a soldering pen, drill, band saw, saws all, small grinder, but very limited grinder use.

I also ordered a 15 amp Morningstar MPPT charge controller for the solar panels. The original 30 amp PWM controller will still be used for additional solar panels, the battery charger and as a backup.

[Daox]

Thats great to hear. It is a very cool project. Thanks for sharing the build.

[oil pan 4]

Here is the new charge controller I need to put on.
15 amp Morningstar sunsaver MPPT charge controller.
For my configuration using AGM batteries I removed the negative load jumper and turned dip switch 1 on.
Dip switch 2 regulates load cut out voltage. I am leaving it off so shut off is at 11 volts, turning it on raises cut out voltage to 11.5v. Since I run a huge power inverter and use that battery for starting leaving the low voltage cut out switch off works best for me.
If you were only ever going to run all the loads through the "load terminals", thus limited to 15 amps then turning the low voltage cut out switch on would be recommended.

Dip switch 3 is equalize, I will turn it on if I ever think I need the panels to equalize for me.



Once installed you will see excessive fusing on inputs and outputs. MPPT controllers can not tolerate a short circuit fault on the input side while charging the batteries.
Each panels will be fused for slightly higher than what it produces and then all the panels together will only be on a fuse slightly higher than their output. Each 80 watt panel will be on a 7.5 amp fuse and then the fuse block will have a 15 amp fuse going to the charge controller and a 20 amp fuse going out to the battery. I figure each 80 watt panel will only produce 4 or 5 amps, so never more then 12 amps going into the charge controller and it will ramp that up to almost 15 amps on the output.

This is very unlike on the PWM controller where I just stuck 20 amp fuses on each panel and wired the fuse block into the charge controller and called it good.

I figure I can throw $10 or $15 worth of fuse holders on there and maybe not have to buy another $240 charger controller if something goes wrong.

[oil pan 4]

Now I can tie the Solar assist: Vehicle roof top solar panels - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com to the home made solar inverter generator.



My UPS plug to MC4 adaptor turns all the roof top solar panels into 1 pair of solar panel side MC4 connectors.



I know its looks short but I have a pair of MC4 extension cables that are 12 gauge and 10 feet long, if I need anything longer I have a bag full of MC4 connectors and two 500 foot spools of 10ga wire.

You may have noticed in another picture I installed a gray Anderson connector on the battery. I use those for regulated battery power only, nothing higher than 14.8 volts.

MC4 and white UPS plugs are for raw solar panels power, up to 22 volts.

You maybe wondering why I have 2 plugs for raw solar panel out put. I noticed the MC4 connectors don't disconnect that quickly. They lock together so if they get pulled on they don't separate. I needed something I could just pull on to separate for my external vehicle applications.

[oil pan 4]

I believe that I have found a proper 50/60hz 120v voltage regulator.
This will allow me to reduce generator speed down to 50hz. Reducing RPM from 3600 to 3000 will save fuel running the generator at light and partial load.
For running the welder and plasma cutter I will need full 60hz power.

[Robaroni]

Hi Oil Pan 4,
The formula for power is P=EI or Power = Voltage times Current. Frequency doesn't change power.

The generator running a 50hz alternator still has to put out 120V , 240V or whatever voltage you need and that takes the same energy and amount of fuel.

One HP = 746 watts, this times the efficiency will basically determine your expenditures.

If the load doesn't change than the power required doesn't change regardless of the frequency.
Rob

[oil pan 4]

I know that frequently doesn't change power.
But the engine makes less horse power at 3000 RPM compared to 3600RPM and the plasma cutter and large welder use every bit of horsepower the engine can make.
The generator will use less fuel at 50hz at low power utilization. I already know they do or I wouldn't bother.
When I was in Africa I took care of generators 50kw generators that ran about 15kw worth of lights. These generator sets were 50/60hz selectable. They would only run for 2 and a half nights on 60hz, before they ran out of fuel but when I turned them down to 50hz they ran 3 nights between fueling no problem.
At low load I expect 50hz speed reduction savings to be between 15% and 20%.

[Robaroni]

You're matching your load more closely with the lower speed but a smaller generator regardless of frequency would have saved you more.

The reason your African generator used more fuel at 60HZ was because it had to run higher speeds to reach the frequency, not the power. Again, if you only needed 15KW you could have used a smaller generator that matched the load closer regardless of frequency. A 20KW generator running at 60 Hz would have used less fuel than your 50KW generator at 50Hz. Your generator was above the power your needed at night regardless of the frequency so running at the lower speed saved fuel.
There is a point of diminishing returns, running a 60Hz generator at no load uses less fuel than a 50Hz generator running a load. If you needed 50KW during the day and you could get it with 50 or 60HZ you would have realized very little if any saving. It depends on the range your engine gets its best efficiency at, if that's the higher rpm than during the day 60Hz would yield better fuel savings.
Power out equals power in minus efficiency losses.

What is the highest power you'll need? That's basically the generator you want. Don't worry about frequency, power needs are the important factor.
Rob

[oil pan 4]

A smaller generator can't run the plasma cutter or welder. 7kw has just enough to run the plasma cutter and can only run the stick welder at about 60% of full power which is fine for pretty much everything.
To run the stick welder anywhere near full power would take a t least a 12kw generator.
Running 50hz at full power is kind of pointless I don't expect it to save a measurable amount of fuel and running at the lower speed will reduce generator output capacity.
Plus I installed a smaller generator in the form of the solar, battery inverter system. 180w of solar (expandable to 210w to 500 watts) and the 1000w pure sine inverter can take care of all the little stuff.
Then my 2000w samlex (not part of this build) can take care of the intermittent medium loads.

The smaller 30kw units were broken. Eventually I reconfigured all the generators around the camp so about 1/3 were no longer needed and I made them my spares. To include the lights, I wired them into another generator that ran tents 24 hours a day. When I got there most of the generators ran between 10% and 30% after I changed things around I had fewer generators running 50 to 60% load.
These were all US made machines.

[oil pan 4]

This is a basic diagram of how the various systems interact.