Does anyone happen to have a Prius Prime & live off grid? Need insight, tia!

I have a farm that does have access to grid power, but we live in an area where the power grid is not reliable. So we also have solar-power powering our home with a battery-bank. With a flip of a breaker, we can be on-grid or off-grid.

I drive a Prius Prime plug-in that recharges from our household battery-bank.

With a full charge, I can drive into town, and back home again before the vehicle battery runs out.

 

Have no experience with the Prime or being off grid, but if you planning going off grid, getting a Kill-a-Watt now would be a good idea. it is a mini electric meter that plugs between the appliance and the outlet, so you can directly measure what energy amount they are using, including the Prime. It isn't expensive, and I am sure there are other brands.

With details on what amount of electricity is going to which appliance, you can make a more informed decision on what you need for PV panels and batteries.

I'm assuming city water and sewer isn't available at this property. if you are on those now, you'll need to factor in the consumption of a well pump. There are solar options that would use their own panels. If there is a hill on the property, or if you are willing to put in a tower, the pump can fill an elevated tank during the day. Then gravity supplies house pressure, so you don't need to run the pump off the battery at night.
The lost opportunity... Solar Deep Well Pump | PriusChat

"I'm not against using a generator"
A poster that was off grid years ago recommended just using a portable generator for high draw items that were infrequently used, like power tools. Though that was before panels and and batteries had come down in price, and there is now a wide selection of cordless drills to lawnmowers to vacuums to choose from.

There are also options besides solar, Eco-friendly hydropower from whirlpools | PriusChat

 

Are you using 39kWh a day? Or generating that much? That sounds really high. I don't think you can use usage at one house as a baseline for what to expect at another, because the large energy wasting devices will likely be completely different.

I don't think we can answer your question without knowing how much electricity you'll use at the new property, and how much energy the existing solar generates. But if you're careful with your usage, you can almost certainly charge the Prime some of the time.

It also depends on your expectations. Do you want 24/7 uninterrupted electricity? Or are you OK with running out occasionally? Do you have a backup plan like a generator for cloudy weeks?

The ~6.5kWh it takes to charge the Prime is not the largest demand in a typical home. For example, things that use more energy (each) than my 30 mile commute include my dehumidifier, my electric water heater, and my air conditioner. Of course in an off grid house you will probably be more careful about large electricity demands.

 

Depending on priorities, there are other options. Propane for heating and cooking is one, and there are fridges that run on that fuel. there might even be propane fridges that also use solar heating to run.

Invest in insulation, as that will reduce heating and cooling demands. Even look into solar thermal storage like used in a passivehaus.
Passive House Institute US (PHIUS)

 

We have 4400 watts of photovoltaic panels, our battery-bank is 48vdc @ 600ah.

We found that starting at 8am we could power every power tool and every kitchen appliance we owned and still put a charge on the battery bank. But once the sun goes down even the electric coffee maker was too much of a load.

 

We are using lead-acid deep-cycle marine-grade batteries.

I installed everything myself.

I sourced our panels from SunElectric. Sun Electronics – World's Lowest Solar Panel Prices

And the Charge-Controller / invertor from WholeSaleSolar.

Honeybees have a lot of problems, a wide array of diseases and pesticide overuse. The 'flow hives' look real cool, but they do not address any problem that honeybees have. I have heard of them compared to installing a boat anchor on your car.

 

As far as your question about the size of the PV system, you just need to add ~6kwh of energy per charge to your system. If you are currently charging your PP, then you already know the amount of kWh electricity usage for each month including the charging PP.

I have been thinking of installing PV panels on our roof mainly to save money but also to be more energy independent. However, the more I research and crank up the numbers, the harder it becomes to justify investing in solar panels at least in my situation. For our climate and for our current household electric usage, the cost of solar panels to provide 100% of our usage installed by a professional installer would be high enough so that the payback period is 13-15 years. If I opt for DIY installation, which I am probably not capable of but just for the sake of comparison, the cost would be about half, and the payback period is also cut in half. This is for a grid-tied system. If I want either off-grid or grid-tied with a battery back-up system, then the cost would double and I would have a much more complicated battery charging system to maintain. Now, instead of using the money for PV, if I put the money in an investment account and let the money earn at a very doable 7% return, no matter how long I keep the solar system and even years after the payback period, the saving the PV provide would never catch up the hypothecal investment account. I even did this calculation at a 4% return, and saving by PV will not catch up to the investment account for the first 30 years. By then I may be dead or even if I am still alive the PV system may need to be replaced. The point is unless the upfront cost of installation of PV panels gets more affordable, it makes no financial sense to invest in my own PV panels.

After all the calculations, I am now leaning toward saving the money in an investment account and signing up for a community solar farm share instead of having my own panel. That way, I will be contributing to renewable energy development without using my money and I get a discount on my electric bills. With the money saved, I can build an off-grid tiny house with a much smaller system when I retire. And who knows, in 10-15 years, PV system may become so popular, that it may cost a fraction of the current cost.

 

That is just over 10,000 kWh/year, almost what my house was burning before serious conservation began (10,600 over a long period, 11,000 over a shorter period.) But serious conservation efforts cut that to just over 5,000/year, and now my PV produces 6,000/year.

If your next house will be custom built, you can design and build it to much better efficiency and comfort standards than your previous houses, saving considerable energy.

You don't show a location. Needed solar capacity will be a very strong function of local climate. I.e. to reach year-round net-zero energy consumption, i.e. I need significantly more capacity at my metro-Seattle location than someone in sunny Arizona would need. And full off-grid solar here would be insane due to the large capacity needed to get through winter, as shown by the seasonal variation of my own production (full capacity not installed until summer 2015):

If you are going off-grid, don't use electric resistance heat, that requires far too much production and storage capacity. Instead, consider some form of gas, or more efficient forms of electricity such as heat pumps for space heat, hot water, possibly even the clothes dryer. The first two are excellent now, but the clothes dryers might might not yet be mature enough for your needs/wants.

My grid-tie solar system was completely DIY design and install. It helped to be a retired electrical engineer, with a bit of electrician skill too (they are not the same), and even did some solar energy harvest investigation for a proposed project on my last contract before retirement.

Re: payback time

I went for a solar system sized for Net Zero Energy Consumption (after serious conservation measures) not for financial return reasons, but rather to put my money where my mouth is towards dealing with Anthropomorphic Climate Change.

Payback time is difficult to figure due to varying incentives and tiered energy rates. Very roughly, tax incentives have paid back about 40% of the installed cost, production incentives (expired June this year) paid about 20%, and eliminated energy bill (except fixed account charge) paid back about 20%. The remaining 20% will be paid back solely by the eliminated energy bill, likely 7-10 more years. Note that this is a solar-unfriendly climate, and I am working with significant neighboring tree interference. Friendlier climates without obstructing trees will pay back faster, but I'm helping prove that it works even in Seattle!

 

That is interesting, thank you for sharing.

We do not have tiered energy rates here in Maine. The power grid is either up and you pay for it, or else it is down so you wait a few days as they make repairs.

Our electric bills are divided in two parts. First is how much power you have consumed, and second is the Transmission charges. Both of these two parts have taxes added on.

Net-Metering systems here, pay for any power they consume and that power is taxed, and when they put power onto the grid they pay the transmission fees on that power and the taxes on that.

I am curious though, if you were to depreciate your solar power system completely over 7 years, how much would that change your projected payback?

 

The cable TV set top box and cable company supplied modem/router are a likely culprit. The company isn't paying for the electric, so they get cheap, inefficient models. Then that set top box, DVD player, game console, TV streaming device, and even the TV, may not actually be turning off, but just going into a sleep mode.

 

We don't have separate transmission charges, it is all rolled into the energy charge. We are still under monopolies here, not a competitive choice market, so there is no need yet to separate those charges.

The legislature set fixed solar production incentives, but the program was capped. My area's solar installations surpassed the cap, so the incentive rate had to be reduced, pro-rated. The legislature established a second incentive program for later solar adopters, but that hit program its cap almost immediately. Bad for people looking for fast payback, but a great sign highlighting the rapid movement to non-carbon energy.

If we had business depreciation available, it would shorten 'payback' only a little, depending on tax bracket. As in-between retirees, post-paycheck but pre-pension, we are in a low bracket. Note that depreciation would guarantee a 7 year payback only in a 100% tax bracket, which doesn't currently exist.