This is just for me.
The vertical shafts pump isn't going back on there.
Probably just going to put a man hoke cover on it and drop a 1hp submersible 240v single phase pump in there.
The 10 turbine pump is a ball of rust, no saving it.
The motor and bearings on the surface drive end are shot.

working towards off grid
 

The lithium Chevy volt pack is re-assigned to home duty. Its around 17 kwh. The 11 kws of solar is charging it for the first time. With the solar exposure of the day we are charging at 4.5kws.

We may include another pack as we have room for it. The last order of business is the 20kw inverter.

The holy grail would of coarse be the Tesla pack however still a little pricey.

There are still some items to clean up with the battery box- proper terminals fusing and a disconnect.
The one last un-known is the thermal management whether in home power duty would cause any heating. I will watch for this. With my experience in automotive duty it wasn't an issue at least for my climate.

Randen. Really liking your system. I think you'll find the actual storage/use/solar input equation to be better than anticipated. I'm anticipating you'll find 180kw of storage as unnecessary.

What controller is that? One of the chinese high voltage pmw?

Creeky

Yes indeed the charge controller is a Chinese PWM high voltage unit.

I'm looking at this as the day is very overcast and still making 1200watts. Our single Geothermal H/P doesn't draw much more and for the most of the winter it provides 90% of the heat and the second unit will provide the balance on those snapping cold days.

The duty cycle for the one unit is approx. 30 - 60% on most days.

This is just back of the napkin calculations and is looking extremely interesting.

Looking forward to the new inverter and even more to see how much of our own power we can use.

randen

The 20 kw inverter is progressing. As this inverter is a DIY some teething problems have surfaced Some new circuitboards have been made with the proper mods. After the next round of testing is complete I will post results with photos

The batteries are fused and fully charged. The fully charged cutoff was observed as we dont want any trouble associated with an over charge

Randen

Working Toward Off Grid
 

As my friend Lynn sent me an E-mail on his tests of the 20kw inverter:

Tada!!! Is all he typed. He likes to put little teasers out to me. Normally he sends a long list of information such as changing traces on boards and signals not present, semi-conductors failing, shorts etc.

So a "Tada" is very appreciated and a phone call is normally made right away. My friend Lynn is a electronic guru. One of those self taught guys with a wealth of knowledge. Me, I'm a basic knowledge guy but technically "I'm learning fast" trying to keep up.

Back to the inverter. This is very exciting!!! 20 kw and capable of double driven from a 360VDC nominal lithium pack. The inverter doesn't exist on the market (for a reasonable sum)

Now the full assembly has not been made yet but most of the pieces are here and preliminary tests are quite reliably positive. The next week or so will be the assembly of the inverter into an enclosure and high power high current testing. We will follow this with a site approval by the proper authorities on the equipment and installation. For my and families well being and the ability to be insurable.

I prefer to be the proof is in the achievement type guy. Id rather have, hot water flowing from my solar collector or Heat out of my heat-pump or in this case current flowing from an DIY inverter before making any claims.

In the photos (if someone could enlarge please) a pair of IGBT boards coupled with some beefy copper buss bars. "think 100A at 240VAC" or "50A at 390V"
Main logic board with sense board.
Battery disconnect "Rated" with Large filter caps meter and contactor.
One Chevy Volt battery pack 17 kwh in a fire proof pit in the garage.

Randen

Inverters that run from 360V or so are very common, but are more commonly called "VFDs". (Although at 20kW, I would expect most of those to run from 480V AC/700V DC. And I would also expect most 20kW motors to be 480V as well.)

NiHaoMike

Well you would think that would work but I tried that. I used a VFD coupled to a 15 KVA 3 phase transformer to provide split or two phase 120/240 volt. Light insignificant loads yes it worked but any load of significant current just faulted out the VFD.

For example any way I had programmed the VFD, for example, the refrigerator would fault the VFD. Tried charging the car at 5 amps but no happiness, the second the contactor closed the VFD switched off.

I'm quite familiar with them but the instantaneous loads are seen as a fault in the motor (transformer) and it would just shut down.

The inverter we are building will cost much less and be more tailored to home use than a similar rated VFD.

Randen

For that use case, I would suggest having multiple smaller inverters rather than a single large one. Apart from redundancy, being able to do V/Hz control on a zone by zone basis is very helpful for fine tuning energy usage. You can even have an output dedicated to electronics which run most efficiently with trapezoidal waves.

NiHaoMike

I appreciate your suggestion but I'm not seeing how that would work. Multiple VDFs and these multiples will each be requiring transformers.

We had done a load test on the home with both heat-pumps operating and the Car charging the Range and oven on as well as the clothes dryer and 2 refrigerators The clamp meter had shown 85 AMPs at 220 VAC. As this is real world worst scenario loads which could happen. I want to supply all these loads with energy captured by our sizable PV system properly and reliably. And I want this to operate like we are connected to the grid. Nice clean pure sine wave. No room for trapezoidal waves

During the summer we want air-conditioning. Winter at outside temps that dip as low as -22 Deg.C we want the heat-pump to operate as normal. We are working towards all this without the power bill and not suffer any ill effects of improper electrical energy. A heat-pump that burnt its windings in the middle of winter wouldn't be acceptable

As I had mentioned we have tested our device and its producing a proper sine wave.
The biggest most difficult part of the device are completed.


Randen