Bad days for Solar Production.

[RV10flyer]

Today I made 16.2 kwh and used 22.4 kwh.
So, I had to use 6.2 kwh from the grid.
December sucks.

17kWh from 32kWpv today. Last week was worse. I had some 7-10 kWh days. I’ve been getting the dust knocked off of those old 100W Renogy. Desperate times when you’re putting 20 in series.

 

[Nobodybusiness]

17kWh from 32kWpv today. Last week was worse. I had some 7-10 kWh days. I’ve been getting the dust knocked off of those old 100W Renogy. Desperate times when you’re putting 20 in series.

You all running all electric or do you have another heat source?
That’s the majority of our usages.

 

[timselectric]

Most of my house is still on gas furnace.
More mini splits are in the plan.

 

[Nobodybusiness]

Most of my house is still on gas furnace.
More mini splits are in the plan.

Ok that makes sense.
I was thinking “Damn am I just wasting energy?”

On mild days with no heat or air I use about 40 kw a day.

1-2 kw per hour.

The lights in the shop mostly pull that with occasional welder, drill, lathe, etc.

 

[RV10flyer]

You all running all electric or do you have another heat source?
That’s the majority of our usages.

It got down to 11F last week, with three dark cloudy days. Still running heat pumps for now. I can do fine on the dark warmer days above 20F at night. Wood burner is locked and loaded though.

 

[RV10flyer]

Ok that makes sense.
I was thinking “Damn am I just wasting energy?”

On mild days with no heat or air I use about 40 kw a day.

1-2 kw per hour.

The lights in the shop mostly pull that with occasional welder, drill, lathe, etc.

30kWh typical daily consumption on these warmer days above 20F. Consumption goes up drastically below 20F.

 

[Nobodybusiness]

It got down to 11F last week, with three dark cloudy days. Still running heat pumps for now. I can do fine on the dark warmer days above 20F at night. Wood burner is locked and loaded though.

Man I don’t know how you do it.
32 kw a day with Heat pumps?

The upstairs unit is new like 15 months old and is 18 seer.
The downstairs unit is 2015 and 16 seer.

Seems like 50-60% of my energy usage is environmental.

I have good insulation.

I used the FLIR to look for any heat losses and didn’t really see any..

 

[RV10flyer]

Man I don’t know how you do it.
32 kw a day with Heat pumps?

The upstairs unit is new like 15 months old and is 18 seer.
The downstairs unit is 2015 and 16 seer.

Seems like 50-60% of my energy usage is environmental.

I have good insulation.

I used the FLIR to look for any heat losses and didn’t really see any..

1.5T 16 SEER d/s, 2T 20 SEER u/s. My 80 gal wh uses 10-15kWh daily. I have 32 kW of pv. Consume about 30kWh daily. I don’t run the power shed mini until it gets below 20F. Plenty of heat losses and R-9 walls in power shed. House R-19 walls, R-30 ceiling. Set temps to 67F day, 64F night, that helps!

 

[Nobodybusiness]

1.5T 16 SEER d/s, 2T 20 SEER u/s. My 80 gal wh uses 10-15kWh daily. I have 32 kW of pv. Consume about 30kWh daily. I don’t run the power shed mini until it gets below 20F. Plenty of heat losses and R-9 walls in power shed. House R-19 walls, R-30 ceiling. Set temps to 67F day, 64F night, that helps!

Well I have an 50 gallon AO smith and it’s just the 2 of us so not to much hot water except for showers.
We do most of the laundry during the day when usually enough PV.

Powershed mini split hardly comes on.
It’s set for 50. Have R30 in ceilings and r19 in walls out there.

Downstairs unit is Trane 3 ton. Upstairs Lennox 2 ton.

Yea I keep house at 73 all day and night in winter so that’s probably why.
Summer 75. Just enough to knock down humidity.

I’m old so I guess that’s where it’s getting spent.

 

[rin67630]

It's not about the kW's you receive it's about how many hours you receive them

I suppose he was speaking about KWh received over the whole day.

 

[Skypower]

Actually November wasn't great either.
My battery bank hasn't seen 100% in 18 days.

Temperate time of year. No need for air conditioning or furnace blower. Blower has been in use but I don’t believe it came on yesterday. Normal day for day appliances, fridge, big flatscreen that never turns off( day&night sleepers) …… and the fish tank all contribute to heat the house.

 

[Skypower]

I probably should buy a heat pump while I can. California is changing the approved refrigerant….again. The new type of system will be twice as costly, limited availability, unproven track record and highly flammable. You know…..total xxxx! But somebody’s gonna get rich

 

[Zwy]

You all running all electric or do you have another heat source?
That’s the majority of our usages.

I run heat pump when I know we will have recharging in next few days. If forecast is mostly cloudy, rain or snow, I'm running the gas furnace.

I have a huge pile of wood from cutting down 23 4 foot diameter ash trees in my yard (and some others) plus all the wood I want 5 miles away. Picked up a wood burning boiler the other day, next year come December and January, I'll heat with wood instead of gas when the sun doesn't shine. Water heater is gas too, but will get hot water from wood if boiler is running.

No heat pump running, we can go 4 to 5 days off battery and the tiny yield on the off days.

 

[Nobodybusiness]

I run heat pump when I know we will have recharging in next few days. If forecast is mostly cloudy, rain or snow, I'm running the gas furnace.

I have a huge pile of wood from cutting down 23 4 foot diameter ash trees in my yard (and some others) plus all the wood I want 5 miles away. Picked up a wood burning boiler the other day, next year come December and January, I'll heat with wood instead of gas when the sun doesn't shine. Water heater is gas too, but will get hot water from wood if boiler is running.

No heat pump running, we can go 4 to 5 days off battery and the tiny yield on the off days.

Yea if I had wood or some other way of heating I could go a week or more on battery.

HP uses most of my energy.

 

[OffGridInTheCity]

Yea that’s one of the reasons I got the biggest panels I could to limit space.

You could have the entire property covered in panels in this dreary weather and it wouldn’t matter now.

As you say, I could do 400 panels on a week of total rain and it wouldn't cover my needs.

I just make enough on Sunny days in winter to cover all electric house.
If I get any overcast or rain then I’m running a deficit.

Similar for me.

I know this is probably a silly question before I ask but maybe get higher amperage panels to add too and replace one at a time your lower wattage panels.

Not practical for me. I'm mostly mono and the more watts is also larger physically and wouldn't fit well on my roof rails and ground array structure.

I'm going to add 8 more on a fence and will do higher watts for 3-4k. And I have 33 panels under the house for emergency deployment to the back yard but that would fill up the yard 120%. I could add another 25 panels on a west facing roof but you know.... and this would be pretty 'in your face visible' and someone might call the city... when is enough enough... ?

My wife has been wonderful up to this point but not willing to do 25 more panels on west roof and I can only do so much sweet talking before she get's suspicious that it's authentic

Or Do like Tim said and just parallel the crap out of them.

I have Midnite Classic 150s and I'm over paneled a bit at 5130kw per 2 of them - works great.



What I'd really like to do... is get a shipping container and have 80 Nissan Leaf EV packs so I could store summer excess into a 4000kwh battery for use during winter. Only 1 cycle per year. And it would be so much fun buying a forklift

 

[42OhmsPA]

Another super productive day.
Definitely adding more batteries (Envision).
Really curious to see how well the new NE solar panels perform on crap days.

 

[SparkyJJO]

But man, keep that bomb well away from your house or anything else you value!

 

[timselectric]

This is why the sand battery is in my plan.
Seasonal storage.

 

[Nobodybusiness]

What I'd really like to do... is get a shipping container and have 80 Nissan Leaf EV packs so I could store summer excess into a 4000kwh battery for use during winter. Only 1 cycle per year. And it would be so much fun buying a forklift

I really considered building bigger battery to do the same.

Problem is I would have to keep the battery near 100% for months.

Not sure that’s good for them.

 

[SparkyJJO]

I really considered building bigger battery to do the same.

Problem is I would have to keep the battery near 100% for months.

Not sure that’s good for them.

You could manually cycle them every so often.

 

[GXMnow]

You running the entire house on 36kw?
I wish I could do that..

My house is very efficient, and I am also cheating a bit.

All my major heating is natural gas. The furnace, water heater, stove/oven, and clothes dryer are all gas.

And then I am in Southern California on the edge of a dessert. Dead of winter hear is about 40F (4.5C) for the overnight low. I have the furnace set at 71F (22C) so I am not asking for a huge temp difference. My walls are bad, maybe R6, but the windows are good Mill Guard triple pane heat mirror. The previous owner did the windows, but didn't bother insulating the walls. The outside of the house is stucco which is not so much an insulator as it is a delay system. In winter it helps as the sun warms the stucco and it releases heat into the house to well after dark. But in the summer it is like being in a pizza oven. While I might not need to run the A/C until 3 or 4 pm, it has to run to midnight or 1 am.

On a good sunny winter day, the Enphase solar panels produce enough power to run the house from about 8:30 am to 3:30 pm. During that time, the extra solar is used to push about 10 KWHs into the 36 KWH battery. The DC panels also push another 5-6 KWHs to the battery. From 4 pm to 8 am the next day, the house uses about 13-16 KWHs or an average of just 800 to 1,000 watts to run the loads in the evening, through the night, and in the morning to sunrise. The battery cycles about 16 KWHs, about 45% of it's capacity.

On a bad winter day, I might only get 5 to 7 KWHs total from both PV systems. In that case, I may end up having to pull 10 KWHs from the grid. As I said, my house is pretty efficient, and the location sure helps. Adding up all of my panels is only 6,800 watts of panels.

The summer here can be a bit of a problem. Sure, the solar panels make a lot more power. But they get so hot, the power drops off a bit, and the Enphase iQ7 microinverters also get hot enough that they even have to reduce output a little. I have whole weeks where the temp stays over 100F (38C) with the peaks going over 120F (49C) on many days. Even setting the A/C as high as 80 degrees, my solar panels might not keep up. Right now I have a conventional Carrier central A/C system with an 18 SEER cooling rating. It pulls 14 amps at 240 volts (3,360 VA about 3,000 watts), plus another 800 watts to run the furnace blower. The Enphase system clips at 3,850 watts. Before I added the DC panels, I fell short by over 6 KWHs every day in the summer. The stucco walls work against me in summer. The house stays fairly cool until the high ToU rate kicks in. So I would be topping up the battery to make sure it could run the A/C from 4 pm to 9 pm as the heat was still coming in the walls. 5 hours of run time at 4,000 watts is 20 KWHs just to run the A/C. The only saving grace is Daylight Savings Time. The long days and the hour shift means that the solar panels were still making enough power to run the house and keep charging the battery out to 6:30 pm. So I was still cycling less than 60% of the battery capacity. In late August though, I had to use some grid power to keep up. The days start getting shorter while it is still crazy hot out.

With the rates as they are now, I am okay with what I have, but if (when) I get a plug in car, I will be way under powered. I think I could add another 1,600 watts of panels, but they will have shade in the early morning. I'll probably lose a full sun hour compared to my current panels. But that would still mean about another 8 KWHs a day in summer. But then I also need more battery to store it.

 

[Nobodybusiness]

You could manually cycle them every so often.

When I get to November I usually start running a deficit so I would have to keep them fully charged or as close as I can from October -December at least to get any benefit.

It might be different this next year as I just got my extra panels up last week.

I will have to calculate it out but it’s probably on the order of 3000 kw deficit for November - December.
That’s in addition to normal usage.

Granted once I started using it in November it would never been 100% again but still holding it pretty high SOC for 2-3 months.

 

[Nobodybusiness]

All my major heating is natural gas. The furnace, water heater, stove/oven, and clothes dryer are all gas.

And then I am in Southern California on the edge of a dessert. Dead of winter hear is about 40F (4.5C) for the overnight low.

I gotcha. NG makes a difference..

The summer here can be a bit of a problem. Sure, the solar panels make a lot more power. But they get so hot, the power drops off a bit, and the Enphase iQ7 microinverters also get hot enough that they even have to reduce output a little. I have whole weeks where the temp stays over 100F (38C) with the peaks going over 120F (49C) on many days.

Everyone has different challenges depending on location I guess.

That’s why so many similar systems act so differently depending on where they are located.

Hard to recommend one system for all.

 

[RV10flyer]

Back up to 100% today. Ready for three cloudy cooler days ahead. Not much sun, but still brought in 65kWh with 32kWpv. Mostly south facing at 45deg. One string SE, two strings SW, both arrays at 60deg for better winter production. Works great for supper, top off water heater and sometimes a little higher setpoints on the heat pumps to use that last hour of sun.

 

[Zwy]

This is why the sand battery is in my plan.
Seasonal storage.

I think the sand battery is well, total bs.

This is part of my plan, using a buffer tank that not only supplies hot domestic water but also can be an electric dump load or run a air to water heat pump to input heat for later use. I'm hoping to reduce wood boiler firing to once a day, probably in evening.

If sand worked so well to hold heat, why did the desert cool off so fast when I was there?

Edit: forgot the buffer tank link