My Solar PV journey is officially ending

[1201]

I think when you do the math and factor in labor and maintenance, solar thermal hot water just doesn't work out compared to solar electric hot water.

Even if you don't use solar for power and only want to heat water with it, electric is the better route. After all the plumbing and pumps and valves and time and up keep, you could just get some PV panels and heat the water electrically.

That's the prevailing wisdom. with Thermal though you can DIY pretty inexpensively but you cant DIY inverters and batteries that easily.
I use about 8kwh per day for hot water so about $350 a year and I think I can put together an inexpensive system for a couple of thou.

Im looking at a smaller version of this system

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[sunshine_eggo]

Mine is fairly easy. 25 amp surge, 9 amp run

120VAC or 240VAC, and was 25A measured with a MAX function or a INRUSH function?

 

[Tulex]

or at least going on a very long Hiatus....

Wish I had thought of putting solar in a lot sooner so that I could have built around it. I can understand where you are coming from. It doesn't financially make sense for me to put my system in. Being near retirement, and the time it takes to recoup the investment, it really doesn't make sense. But, my tin foil hat is nudging me. If I've learned anything over the last few years, it's that the future is getting harder and harder to predict. In reality, there is no down side for me. Self reliance and piece of mind have value, as will the solar system when it comes time to sell my house. Until then, I will have a very expensive UPS.

 

[1201]

If it "sits about 75 degrees" on sunny days in the winter, what does it sit in the summer?

in the summer the windows are covered with 90% solar screen so its not bad. I put up the screens mid april(will be doing it this weekend) and they come off end of october. Before the screens the house with no HVAC would get to 102 degrees. with the screen low 90s, like a regular house

 

[1201]

120VAC or 240VAC, and was 25A measured with a MAX function or a INRUSH function?

240v, and I used the inrush function on my meter

 

[sunshine_eggo]

240v, and I used the inrush function on my meter

I asked because that's low. Typical surge is about 5X run.

A robust 24V/3kW unit with 3X surge (Sigineer or AIMS type) plus two big AGM batteries you would keep floated via grid could be had for about $1K. A suitably sized standard generator would run you about the same. The difference would be run time. The AGMs would run the pump for a couple hours. The Generator would run the pump for some time, and would be easy to refill from a gas can.

 

[SamDeleted]

heat pumps are NOT designed cold weather efficiency

I love that , heaters that don't work well in the cold


Whats next - air conditioners that dont work when it's warm out lol ?

 

[1201]

I love that , heaters that don't work well in the cold


Whats next - air conditioners that dont work when it's warm out lol ?

They all publish BTU at different temps so you just have to size accordingly

 

[1201]

I asked because that's low. Typical surge is about 5X run.

A robust 24V/3kW unit with 3X surge (Sigineer or AIMS type) plus two big AGM batteries you would keep floated via grid could be had for about $1K. A suitably sized standard generator would run you about the same. The difference would be run time. The AGMs would run the pump for a couple hours. The Generator would run the pump for some time, and would be easy to refill from a gas can.

I was surprised too. I measured several times.

Hey that's some good info. Can I ask why you prefer 24v to 48v for a well pump backup? Thanks

 

[sunshine_eggo]

I was surprised too. I measured several times.

Hey that's some good info. Can I ask why you prefer 24v to 48v for a well pump backup? Thanks

Your run power is ~2000W, and I had a specific inverter in mind.

 

[LittleLebowski]

I don't even care about breaking even, I care about being independent.

 

[1201]

Your run power is ~2000W, and I had a specific inverter in mind.

Which one?

 

[sunshine_eggo]

Which one?

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Made by Sigineer, who also makes AIMS. Looks like it's available in 48V as well, but only 12 and 24V are stocked in US.

Neighbor used the 24V/6kW version to run his 3hp Grundfos (18-19A run).

 

[1201]

I think when you do the math and factor in labor and maintenance, solar thermal hot water just doesn't work out compared to solar electric hot water.

Even if you don't use solar for power and only want to heat water with it, electric is the better route. After all the plumbing and pumps and valves and time and up keep, you could just get some PV panels and heat the water electrically.

I should also mention that with pv, it's more difficult to switch back to the grid during cloudy periods. You have to have a transfer switch. But with thermal, the grid is still hooked up. If no hot water comes from the solar thermal system grid just steps in to heat the water. More seamless.

 

[dcg9381]

They all publish BTU at different temps so you just have to size accordingly

All the energy conscious Texans (and most are not) care about is SEER. And that's find normally, a snap of more than 2-3 days below 30 is very unusual. But when it hits, many of these units (including mine) cannot produce heat worth a crap via pump.

 

[dcg9381]

I asked because that's low. Typical surge is about 5X run.

This is really important to know. Our normal household draw is 2-4kWh. We could run all day on all sorts of single inverter solutions with 1-2 batteries.

Monthly peaks are 16kW - and that's probably not even the "per second" peak, so that's a huge amount of power to have to have batteries handle.

 

[dcg9381]

so they've fixed the problems? good to know. I didnt lose power or water but I knew people who were without BOTH for up to a week. It was terrible

Debatable. Mandates were put in place for fuel providers to "winterize" but I also know that those mandates included "buy out" options for a very small sum of money. What I can say is that ERCOT kept up in 2023.

The local utility and ice - that's highly regional and specific to little units of control. Trees took a lot of damage so a lot were removed, but is this problem solved "long term" - not unless more aggressive maintenance is performed.


The problem in 2021 resulted in me installing a 20KW generator and an alternative fuel system to heat the home without electric (propane alone). We did fine in 2023 and I'm able to switch to propane as a heating source below 30 degrees.

 

[rhino]

I should also mention that with pv, it's more difficult to switch back to the grid during cloudy periods.

Not sure exactly what you mean by this but there are plenty of systems that automatically switch back to the grid when batteries are low or use a current transformer to simply generate as much electricity as possible to offset using grid power but the entire system is still connected to grid power for when it is cloudy or at night.

 

[1201]

All the energy conscious Texans (and most are not) care about is SEER. And that's find normally, a snap of more than 2-3 days below 30 is very unusual. But when it hits, many of these units (including mine) cannot produce heat worth a crap via pump.

we got down to 3.6 degrees in 2021. the heat pumps would have kept up. They have full output down to 17degrees and are only a little down at 5 degrees. Im really happy I installed them to. The soft start on them is beautiful!!! as a bonus I saved 20k over what the contractor wanted for 13seer single speed units :D

Debatable. Mandates were put in place for fuel providers to "winterize" but I also know that those mandates included "buy out" options for a very small sum of money. What I can say is that ERCOT kept up in 2023.

The local utility and ice - that's highly regional and specific to little units of control. Trees took a lot of damage so a lot were removed, but is this problem solved "long term" - not unless more aggressive maintenance is performed.


The problem in 2021 resulted in me installing a 20KW generator and an alternative fuel system to heat the home without electric (propane alone). We did fine in 2023 and I'm able to switch to propane as a heating source below 30 degrees.

I'm going to install a wood stove for heat if we lose power for an extended period

 

[rhino]

What kind of power generation is your grid power coming from?