Anyone working toward Off Grid

[creeky]

Oilpan, you might want to look at the new Victron 10kw inverter. Two of them together make 240 split phase and 20kw steady hour after hour.

The chinese have some higher voltage inverters. 96 and up.

Need something of the battery pack for these.

[oil pan 4]

Yeah the radians and a few others are stackable for something up to 70kw, then if you want more you have to buy an additional controller.
And as far as I can tell still only use 48v.

[creeky]

Yo Power / Hefei have three phase inverters for high voltage.

The 30kw linked here starts at 240v, offers 380 and 480v.

[randen]

I had a look at these before I built my own. They were still quite pricey not to mention shipping. The inverter has a huge transformer that weighs allot and I see they didn't indicate the weight, which if remember was over 200 Kgs and shipping was estimated at just under $3000.00 to my door.

30kwh is huge, even half that is hard to satisfy with enough panels and batteries.

Randen

[creeky]

I would talk with the sales rep there. They seem to have all kinds of stuff that doesn't get into the websites.
I was shown a 96v inverter. Small 5kw. But it was really inexpensive.
You're right about the weight tho. Even the 64v/5kw they built for me was 60kg.
They seem to be very fond of big ol' transformers.

[randen]

How about an update.

The inverter has been operating very well however with all the draw necessary for the winter season and the lack of sun my batteries are not up to the task. I get to about 2:00-4.00 in the morning before running out of energy.

A large investment into batteries is required however at this point in time its not possible. ($$$) Another Chevy volt pack will be sourced and for ideal days we will operate off grid.

With heat pumps running albeit not hard on days with good solar resource and 2 chevy volt batteries we should be able to be autonomic through the night to hopefully receive sun the next day

Currently I have it apart for some up-grades:

1/ I want it to control the charge from the solar panels.
2/ moderate both the cooling fan and pump speed with heatsink temperature.
3/ overtemp shutdown incase pump or fan fails.
4/ operate a transfer switch between grid and off grid

These items should round the inverter to a nice all in one box answer to no compromise solar off grid.

Randen

[randen]

Some items have been stroked off the list. The inverter is now also a charge controller so the high voltage Chinese control is available for sale. I purchased another small coolant pump, very quiet. I can hear our cat purr over the sound of the inverter. Yet is to incorporate the speed control for the pump. The fan cooled radiator for the heatsink is on its own snap switch as the heat may increase in relation to load the fan turns on. As it is cooler in the garage most of the cooling is accomplished by convection through the radiator and as a result the fan seldom operates. This delightful radiator's fan is a two speed tangental fan that is mostly silent.

Best news. We have another Chevy Volt pack. This should make us near autonomous

The Mrs put the system through it’s paces cooking on the stove top and a roast in the oven while washing clothes with the geo- thermal heat pump running and AND the car charging albeit at a reduced rate. But there it is uncompromised!!!

Now this occurred before the 2nd pack and we ran out a 7:00 pm

My calculations leaves me to the fact a 3rd may be necessary. The inverter has the brawn to supply all the loads. The mission is to collect enough solar energy through the day, store it and power our lifestyle through the evening till the next morning to repeat.

Sadly, I tried to make a deal on a Tesla pack but price wise their still up there with starman

On another front Mikesolar has a few more solar panels for me. We’re going to increase the PV to 14.5 kws as we still have room available on the roof

We are nearly there!!! Off grid. But we will keep the grid connect for the rare day we may need some backup

Randen

[randen]

Ah yes!!!

I believe the off grid season is here. Currently the second day off grid. The day-length is longer and the demand for the heat-pump is lower with more warmer temps. More sunshine less overcast.

Yesterday full sun charged the two packs fully as well as the car. The in floor heat also was charged by the solar hotwater collectors.

Supper was cooked on the electric stoves well as warming some food in the electric oven with still an abundance of power remaining.

Woke with still a good amount of energy in the pack to be topped up again with a day of sun.

Off grid with no compromise ?? Can be done!!!

Randen

[stevehull]

I would LOVE to be off grid. But ecology, time, health and family all interfere.

In the meantime I make use of geothermal heat pumps, a minisplit for the shop and a 12.5 kW solar system.

I have real issues with lead acid batteries. They don't last long, require a lot of maintainance, outgas incredidly toxic hydrogen gas and then we can address the toxicity of lead. Energy storage for night and cloudy days is a must and the alternatives are not easy or inexpensive to impliment. This will change in the next few years where energy storage will not be $100 (or more) .per stored kWhr.

Our 12.5 kW PV system (self installed) has reduced our power consumption by about 80%. I have an FLIR IR scanner and have butted up the houses tightly. HRV's are necessary for ventilation and LED bulbs are in all sockets. That was all done first.

I gave a LOT of attention to a 10 kW wind turbine, but this is simply not a self install system whereas the PV system was nuts/bolts on the barn roof. A 10 kW wind turbine was over $40 k, where I did the PV system for half that. By coincidence the inclination (3/0 pitch) and perfect southern roof exposure work perfectly.

This time of year we get about 80-90 kW per day (sunny and cool). In a month the solar radiation is higher, but so is the temp (degrading PV performance. I purpously mounted the panels about 5 inches off roof to allow convective air flow. A real advantage is the barn is a lot cooler in the summer.

The time issue is critical. I live on a 40 acre livestock farm with only me to do all the farm work. As an engineer (MS, electrical) I am not daunted by the technical issues, but wife, three kids, two grandchildren - there is not a lot of discretionary time. Then I do a fair amount of energy consulting and THAT eats time, but helps put groceries in the larder.

I could do a whole page on health - but the short take is that I do chemo every other week to treat an inoperable gut tumor. Chemo week sucks, but I am in my third year after an initial diagnosis of 4-6 weeks. The chemo keeps the tumor in check. Not everyone has this condition and I envy the energy I had in my 20's to 50's. Just assumed it would always be that way - not.

But I love hearing of your creativity, and clever approaches to energy consumption, Keep it up!!

Steve Hull

ps forgive the bad spelling - neuropathy makes typing tough

[randen]

Stevehull

The aging process can be sometime a little rough. I too find a big push is necessary to get somethings accomplished. But keep up the good fight.

The system is performing very well. The inverter is really cranking out the Kws without breaking a sweat. The liquid cooled IGBTs is imperative.

Today I'm installing a little PWM circuit to moderate the coolant pumps speed to the heatsink temp. With the exception of a tiny whine of the pump the inverter is silent. The big finned heatsink with two squirrel cage fans was a definite no go.

The seemingly endless days with overcast conditions force us back to grid power. So this summer a couple additional items are planned.

I should add that we do spend many days now off grid and have saved from January till April over $500.00 in electrical costs.

More solar panels AND a wind turbine are planned.

On the roof there is enough room for another 3.5 Kws and the cabling is already there waiting.

Wind is going to be some work. And this will take some time as this is going to involve some structure and some buried cable.

We have received a small turbine for a proof of concept. As with most products today they are still designed around lead acid so 48 volts. We are looking to a circuit to boost it to our battery voltage of 390 VDC from there we will direct it to battery or dump load.

I will elaborate on these plans as they are in process.

For now I'm quite pleased with the system. With the extended daylight hours and improving weather weeks off grid is the norm until we encounter thick overcast conditions for the excess of a day. A thin overcast will still provide us with enough energy to remain off grid.

We have enough to operate the house with normalcy. My wife cooks over an electric cook top and sometimes an electric oven is used. A dishwasher and washing machine are also in the mix and this happens while the sun has already set.

Now we can't get too crazy like expecting to charge the car and run the clothes dryer or having the heat pump running through the night. These high draw devices have to be started during daylight hours.

The Tesla battery pack is sill in the sights but we are waiting for the better prices.

Randen