How to get SunPower Solar Panels for a skoolie?

[TomA]

Originally Posted by dzl_

Your comment implies there is no single point of failure. Does this mean they are fully decentralized, no centralized unit or anything needed?

I am no expert, but:

Micros live on the AC (grid) side of your setup. They are independent from one another, which makes them so effective at operating in part shade and different solar exposure/orientations.

In this world, there is Enphase, and then everything else. The Enphase micros are usually monitored and controlled by a centralized Envoy gateway box that also produces data for you. I think the IQ micros will work without the Envoy, but I'm not sure. There are also other gateways to sync 2 and 3 phase systems, etc. Enphase has driven most of the other mfrs out of the business. There are stand-alone Chinese micro-inverters that can be controlled via phone app, but I have no idea if they actually work. This market is changing really fast and I'm not current with the DC optimzer config, so somebody who really knows these systems should chime in here...

Most (now) obsolete micro setups (like the SunnyBoy) have a similar, proprietary architecture of many micros to one "gateway" or slightly different "aggregator" device that collects data and/interfaces with the grid. Remember, they are grid tied and won't work if the grid the expect to be tied to isn't functioning. In the absence of the voltage and frequency they want to see, they cut off (presumably so you aren't putting power into a downed grid, which could injure someone working on it elsewhere.) This last bit is controversial:

It means your panels WON'T WORK during a power outage. It also means (under Rule 21 in California) that the utility can control your micros through the grid and just shut them off in the afternoon if they don't need the power. Older micros aren't Rule 21 compliant (utility controllable) and the whole thing is now a bitterly f'ed up squabble. Google "anti-islanding" and "CA Rule 21" and you'll get a glimpse of what is going on.

Originally Posted by dzl_

second, can you elaborate on this:
What does "dependent on a grid sine wave" entail

This is "anti-islanding" and it is accomplished with software in the system components that prevents the micros from operating independent of the grid, or as islands of power. Without the grid powered at 115/230@60Hz connected to them, micro-inverters shut down and output no solar power. Period. Even before Rule 21. Maybe a safety feature. Maybe a utility anti-obsolescence scheme. Sucks for the user either way. As I said- controversial...

Originally Posted by dzl_

What is the process of getting the energy from the microinverters into the batteries? Do you just wire the microinverter outputs to the AC panel and let the inverter/charger take it from there?

Generally yes, but if your inverter/charge doesn't generate a grid-side AC waveform and act like the power grid, the anti-islanding built into your micros will prevent them from outputting AC. You also need to manage their output, and most inverter/chargers won't do that. They expect the AC input source (grid) to be regulated upstream. The Envoy will do it, the Chinese micro app might do it, but this is where it gets complex and frankly beyond my depth, so I'll shut up now until I have it sorted for myself.

Originally Posted by dzl_

Finally, have you looked into the dual efficiency loss associated with converting DC to AC and then back to DC? Do you have any estimate on efficiency penalty we are talking about.

A little. Micros are very efficient. The big inverting inefficiencies generally come from stepping power way up and down in voltage, so a 48V DC bank that is inverting back and forth to 115V AC loads and charging is going to be more efficient than wider gaps, like from a 12V battery bank to 230V AC loads.

For me it isn't about going back and forth DC-AC-DC so much, because you always have to do some of that. I'm using micros for other reasons, though. AC devices are substantially more efficient at 230-240V than at 115V, which is why only North America bothers with 115V AC at all, and big high efficiency minisplits are all 230V. A 230V refrigerator, induction cooktop, water heater- everything- is more efficient than a 115V unit.
I'll probably run the battery pack at 48V, the appliances at 230V.

With Micro-inverters producing 230V at 97%+ efficiency, on a hot sunny day I'll be getting the 230V I use straight off the roof (micros) without going through the charger, then the battery bank, then the inverter, I'll have the highest efficiency architecture when I'm in max load. Running the AC all night long off of stored and re-inverted electrons will be less efficient, but I'll have the most efficient power when I need it the most. By programming laundry, baking, hot showers and other high drain AC use into full sun hours, I not only get better efficiency doing it, but I spare my battery the duty cycles of storing and discharging those electrons at a different time. Everybody would benefit from doing that no matter how they generate power.

I also NEVER want panels pushing out DC power into the roof wiring harness or into the coach without regulation, but I'm persnickety that way and nobody else cares about it. TBH, for that reason alone I'll be generating AC power.

But no, to answer your question, I haven't really run the numbers. If you overwhelm the problem with capacity, (5-6kW of generation, 20kWh of storage) you don't have to...

[Truffles]

Originally Posted by TomA

I am no expert, but:

Micros live on the AC (grid) side of your setup
[...]
Remember, they are grid tied and won't work if the grid the expect to be tied to isn't functioning. In the absence of the voltage and frequency they want to see, they cut off
[...]
It means your panels WON'T WORK during a power outage.
[...]
but if your inverter/charge doesn't generate a grid-side AC waveform and act like the power grid, the anti-islanding built into your micros will prevent them from outputting AC.
[...]
For me it isn't about going back and forth DC-AC-DC so much, because you always have to do some of that. I'm using micros for other reasons, though. AC devices are substantially more efficient at 230-240V than at 115V
[...]
With Micro-inverters producing 230V at 97%+ efficiency, on a hot sunny day I'll be getting the 230V I use straight off the roof (micros) without going through the charger, then the battery bank, then the inverter, I'll have the highest efficiency architecture when I'm in max load. Running the AC all night long off of stored and re-inverted electrons will be less efficient, but I'll have the most efficient power when I need it the most.
[...]
I also NEVER want panels pushing out DC power into the roof wiring harness or into the coach without regulation, but I'm persnickety that way and nobody else cares about it. TBH, for that reason alone I'll be generating AC power.

So how will you feed your batteries with the AC produced by the micro inverter setup, when not tied to the grid?

[dzl_]

Originally Posted by TomA

snipped

Great response, thank you for taking the time to articulate your strategy and explain a bit about microinverters.

Like Truffles, I'm curious how you will trick your microinverters into producing when there is no grid power?

Re efficiency:

I can see how for your model, using mostly AC appliances and mostly during peak sun, micro-inverters might make more sense.

In that energy going directly to powering loads would only have a single DC to AC conversion at the micro-inverter. The remainder would go DC-AC-DC into the battery and then one more DC-AC conversion at time of use. So the full path for stored energy would be DC-AC-DC-AC (and then often a final AC to DC in the device itself).

As you said micro-inverter efficiency is very high, so if you can use the AC directly from them, this is the most efficient way to do it. But in terms of storing the energy for later use, all those conversions will add up. (95-98% microinverter efficiency + 85-95% charger efficiency + 85-95% inverter efficiency).

Though as you said, if you have the space and funds to throw enough panels and batteries at the problem, efficiency losses aren't necessarily dealbreakers. I tend to obsess over efficiency but I understand that not everyone cares so much.

[Drew Bru]

Originally Posted by Truffles

I'm not a solar expert by any stretch of the imagination.

But my reasoning for choosing microinverters was because they allow you to have partial shading on some panels without affecting the output of the other panels. I figure that I will have limited options on parking spots, and that if I am unable to find a place free of shade then it may make the whole solar array unusable. As is shown in the youtube video linked below. I won't be offended if you tell me I'm dumb

https://youtu.be/QzzB1i1w_kM

Our panels supposedly take care of the partial shading issue, due to their "unique twin design", though I haven't tested it. I didn't buy them with that in mind, it just so happened to be the case.

https://usa.recgroup.com/products/rec-twinpeak-2-usa

[dzl_]

Originally Posted by Drew Bru

Our panels supposedly take care of the partial shading issue, due to their "unique twin design", though I haven't tested it. I didn't buy them with that in mind, it just so happened to be the case.

https://usa.recgroup.com/products/rec-twinpeak-2-usa

Panels with half-cut cells are good for partial shade, they usually have 6 groupings of cells instead of the usual 3. So the corresponding power loss from one group being shaded is less than a traditional panel. at least in theory. This is also quite dependent on the orientation and amount of shade. Below is an illustration of how half cut cells can improve partial shade performance. the bypass diodes (little triangles in the diagram) let current flow around a shaded portion, because the groups are smaller in a panel with half cut cells, less cells will be bypassed in the event of shade.




However what microinverters and multiple mppt controllers do is somewhat different. Half cut cells and wiring in parallel are shade mitigation strategies (minimizing losses) whereas micro-inverters or multiple MPPT controllers mitigate and optimize. It moves the algorithmic MPPT magic from the array level (where the MPPT controller is optimizing for the average conditions across the whole array) to the module level so each panel is optimized for independently of the others. This makes little to no difference in uniform sunny conditions, but it can make a difference when there are differences across the array (such as partial shade, different angles or orientations, etc). I don't know how much improvement can actually be expected, I haven't seen any numbers, and its not the easiest thing to test with so many variables. But for ideal partial shade performance module level optimization of some sort probably makes sense. However for most, the juice may not be worth the squeeze, and of course there is no substitute for just avoiding shade.

[TomA]

Originally Posted by dzl_

Like Truffles, I'm curious how you will trick your microinverters into producing when there is no grid power?

The Sigineer inverter/charger does that. It generates 230V or 115V at 60hz pure sine wave on the AC side, so the micros think they are connected to the grid. The Sigineer can then vary that frequency up to 62.5hz upon command, which the micros interpret is out of range, (loss of grid) and shut down panel output.

Originally Posted by dzl_

In that energy going directly to powering loads would only have a single DC to AC conversion at the micro-inverter. The remainder would go DC-AC-DC into the battery and then one more DC-AC conversion at time of use. So the full path for stored energy would be DC-AC-DC-AC (and then often a final AC to DC in the device itself).

As you said micro-inverter efficiency is very high, so if you can use the AC directly from them, this is the most efficient way to do it. But in terms of storing the energy for later use, all those conversions will add up. (95-98% microinverter efficiency + 85-95% charger efficiency + 85-95% inverter efficiency).

You're getting wrapped around the axle on these steps, several of which are unavoidable so they don't matter very much. Using power at night necessarily means charging losses and later inversion losses, which are ten times higher than using solar power directly either way. Microinverters offer no real efficiency improvement there.

In bright sun, the micros provide power directly to the load at 97% efficiency, bypassing the inverter/charger. Saves the DC-AC inverter loss and load on the device, which frankly is all probably low, but it also means I don't need such a big DC-AC inverter running at full chat all day.

Keep in mind there are other important inefficiencies. Wiring is a big one. Panels are another. The difference between 18% efficient garden variety panels and 20.5% efficient SunPowers is greater than all the different device architectures we are discussing. A little dust on the panels far more than that. Got to keep a wider perspective. Cheaping out on low efficiency devices all around but then obsessively hosing and squeegeeing the panels off every day is a perfectly legitimate strategy...

[dzl_]

Originally Posted by TomA

You're getting wrapped around the axle on these steps, several of which are unavoidable so they don't matter very much. Using power at night necessarily means charging losses and later inversion losses, which are ten times higher than using solar power directly either way. Microinverters offer no real efficiency improvement there

It would be fair to say I care more about efficiency than most, but I disagree with what you said above. All of these steps can be avoided or minimized in most cases, and taken as a whole conversion losses can add up to a substantial amount, it just depends where your priorities lie and what your designing for.

Microinverters introduce two additional conversions for stored energy. The first is pretty efficient ~97% apparently the second is less efficient call it 88%, that's 15% wasted just on the charge side, 20-30% if you account for inverter losses. Then there is idle power draw of the inverter and charger, but that's a separate issue, that is unavoidable for many people.

If you have a large system this is not a big deal, but skoolies are naturally space constrained, especially short ones. Not everyone can add enough panels to ignore efficiency.

There is no one size fits all solution. As I said above, I think your model will probably work for you. I get the feeling you are building a pretty large system, with a decent amount of household appliances and creature comforts. Most of your electrical consumers sound like they will be AC, and can be scheduled in the day. So your system may be optimized to your use case. And I'm actually quite interested to hear more about it, and see your eventual build. Its not something I had ever considered for a mobile build before, and a very different model from my own, which I feel I can learn from. I don't think it would be well suited for me, but I can totally see how it would work for a certain type of build and usage pattern.

But many people primarily consume power outside of peak sun hours and/or peak sun seasons, so optimizing for stored energy makes more sense in those situations. Further, many people have very few or no always-on AC loads, so sticking to DC has the dual benefit of minimizing conversion losses and eliminating idle power losses by switching off the inverter+charger when not in use. It is common in many marine builds for instance to only turn the inverter on for a few hours a day as needed.

If someone has the space and money to not worry about efficiency, that's great, one less thing to think about. Or if someone like you has thought through your needs, and designed something that works for you, you won't get any arguments from me, I think your system sounds well matched to your use case.

But don't paint with two broad a brush. For many (I would think most) mobile off-grid use cases, efficiency is a top tier concern, and the less conversion losses and idle power consumption you can have the better.

Personally, 90% of my expected devices are DC, and I will consume most in the evenings, so its (1) easier, and (2) more beneficial for me to cut out unnecessary conversion.

Keep in mind there are other important inefficiencies. Wiring is a big one. Panels are another. The difference between 18% efficient garden variety panels and 20.5% efficient SunPowers is greater than all the different device architectures we are discussing. A little dust on the panels far more than that. Got to keep a wider perspective.

Yes, definitely have to look at the whole picture (and as an aside that picture definitely needs to include habits). Wire losses matter, and panel efficiency matters (but only if higher efficiency panels allow you to fit more panels on your roof which is not a given, Watts are Watts and a 300W panel will produce the same 300W whether its 5% or 50% efficient). Heat is another factor effecting efficiency.


I think the a broad takeaway we can both agree on is consider the big picture, don't get overly hung up on any one specific factor, but cut out inefficiencies where you can, in a way that makes sense for your usage.

Cheaping out on low efficiency devices all around but then obsessively hosing and squeegeeing the panels off every day is a perfectly legitimate strategy...

This would actually be a really interesting test to see energy generation over time of panels cleaned daily vs monthly vs never.

[TomA]

Hey dzl, we are in agreement and I didn't mean to insult you. As you correctly suggest, I have my biases and they affect my judgment until I notice it. I never really considered DC appliances because they are so costly. Since I need 250+ square feet of coach space, that stuff doesn't match up well with my footprint anyway. Lucky me...

Solving for x in my build, I would rather put cheap, even used consumer appliances on board and put the dollars saved into my infrastructure. I'm not rich and my build isn't for luxury. Its actually very cost conscious:

SanTan currently has used 250W Sunpower panels at $90. 5500 Watts of that would fit on a 40 footer for less than $2k. Non-Rule 21 compliant (obsolete) micros can be had, brand new, for under $100 per panel. The inverter charger I want is under $1000, but I really want two of them. I won't spend more than $2500 on a battery bank, so 20kWh is a little out of reach ATM, but its less important because I have overpaneled the problem so much. Total infrastructure budget from the roof rivets down to the wire ties and GFCI outlets is $9000, which sounds like a lot. but is to my mind the cheap way to go. I can then source the load side at pennies on the dollar- buy a used apt fridge on craig's list for $75, garage sale toaster oven, etc. I don't need a generator. I won't have gas on the rig. I will never connect to the grid unless the coach is parked indoors for storage. Best set of compromises for me, and no hot DC pigtails coming off my roof or panels, which is my own peculiar top priority.

On a much smaller scale, like a van or shorty, (or especially a sailboat) DC everything is really smart. The offshore guys have everything at 25V (24V?) because that's about the highest non-lethal voltage you want to wade around in if you have to, and all their stuff is super efficient. OMG its expensive, though. All the money in such a setup is on the load side, but its small and top quality, with no AC at all to kill you at sea. Everything is a compromise...

[TomA]

Originally Posted by dzl_

This would actually be a really interesting test to see energy generation over time of panels cleaned daily vs monthly vs never.

Very interesting study right in the wheelhouse of your interest:

https://www.google.com/url?sa=t&rct=...Sz2IEdiwYJ4Dy0

My take on it:

1. Dry wiping is ok and cost efficient (one of their big issues) but water cleaning is much more effective.
2. Regular cleaning is worth up to 5%, maybe double that if you use water. An infrequent rain seems to be worth 11%...
3. I think vehicles, being more negatively charged and attracting dirt as they do, would see even higher performance increases, but that's my bias.

[JDOnTheGo]

Tom and DZL, you guys are doing a great job! This electrical system approach is new and different - it's great to see people listening, adjusting their thinking, and having a conversation!!

I've certainly had to spend some time adjusting my thinking to this new (to me, at least) approach. It just seems wrong given years of typical RV type setups. Obviously, it isn't wrong - as already stated - just different. I too am very curious to see how it pans out.

[joeblack5]

I have tricked an enphase 7 micro inverter in delivering back. It is fairly easy to simulate with variable Dc power supplies, a steady load ( light bulb) and a variac ( variable AC power supply).
Doing that with variable loads would be more complicated. Using a normal inverter as mains to trick the micro inverter to come online would be impossible since the inverter can not absorb current. So if the solar delivers more power then your load absorb the inverter needs to absorb the rest, the grid would normally do that. As a result over voltage and the micro inverter switches of or the inverter blows up.


TomA,
quote
The Sigineer inverter/charger does that. It generates 230V or 115V at 60hz pure sine wave on the AC side, so the micros think they are connected to the grid. The Sigineer can then vary that frequency up to 62.5hz upon command, which the micros interpret is out of range, (loss of grid) and shut down panel output.



Can you reference the article/ specification where you found that information




The inverter would need be able to absorb the current ( micro inverters are essential current sources) that varies with the sunlights power.
A charger or variable load can do that but there would be considerable communication going on between the low power dummy inverter that tricks the micro inverters on coming on line and the micro inverters that do the power lifting part of the inversion.
Then when the sun is down and the micro are off line the dummy inverter has to become the power inverter to deliver all the power to the loads.


If your battery is less then 160 Volt DC for 120VAC or 320 DC for 240VAC so for instance a 24VDC or 48VDC battery bank then your main inverter has some good size stand bye losses.


Johan

[joeblack5]

TomA,


I found the equipment you mentioned.


https://www.sigineer.com/product/600...z-freq-switch/



$1395



Very interesting,.... to circumvent some problems with grid tie micro inverters on one of our rental properties.. so thank you for bringing that under my attention, certainly the solar installer company did not do that..



For mobile and in the shade the 60 watt stby losses of the this 6KW inverter are pretty high.



Johan

[TomA]

Jack Rickard has been playing around with these inverter/chargers, Tesla and LiFeP04 batteries, many other components and a major solar array for 3-4 years. I've been following his work since 2008, and met him about 10 years ago. He started with electric car conversions, but has gone primarily solar/storage/offgrid since. He's been playing around with that stuff for more than 25 years.

When I say "playing around," what I really mean is he's a careful EE with lots of resources and experience (he has specified Sigineer to build configs to his specs, which he resells, he has developed and sells Tesla battery management gear, an electric vehicle control unit in its 4th or 5th generation and more...) Jack's very smart, code savvy, and works quite methodically. Not afraid to ruin stuff, either.

You should take a look what he's been up to:

EVTV Motor Verks - Custom Electric Car Conversion Instructional Videos

[TomA]

Johan:

You are getting around to the central obstacle I foresee to making the system I want to operate in the following critical mode:

How to get the micros to support a variable AC load when the batteries are full or otherwise can't absorb the excess output of the full array.

I suspect that I'll have to size the array and storage bank more carefully around the loads to minimize or eliminate this mode completely, which would mean I can't overpanel and underbank the expected load as I want to do, and will be much more limited in my reserve capacity and flexibility. I'm optimistic there is a solution that isn't so limiting, though. Being able to control the array output at the panel level would very nearly solve the problem, for instance, reducing array output one panel at a time until it falls below the 230V load + bank charging load - safety factor, and ramping it back up if the (expected highly) variable load increases.

I'm neither an EE nor a coder, and I'll need some help with that, as I can't afford to blow up components and start over twice or thrice. Having Jack Rickard out there dynamiting boulders and paving the road so far has been essential to what I'm trying to do electrically. When I'm ready to not waste his time, I'll know who to ask...

[Native]

Talking off the top of my head here ...


Wind turbines need to have a load/sink at all times. Perhaps the wind power generation industry might have a solution lurking out there for you.


Attaching a dump load that would turn on when certain conditions are met might provide the safety net you are looking for. I have no idea what that might look like. Pretty much any useful task that could benefit from an energy source that will not be constant without causing problems with the task (such as heating water or distilling water or other substances) might be a candidate for such a load.

[joeblack5]

I am familiar with Jack and his company, I have build a couple of non glamorous lead and now lithium electric car conversions myself, we drive them every day.



I am not seeing your problem with the sigineer inverter (that seems to be made in China.) It takes care of the whole thing.
If your batteries are full then your solar shuts of, same with this micro inverter technology or straight DC technolgy.


You can divert electrical energy into other storage means.. hot water, ice, H2.
My experiments with the enphase 7 educated me in some variable load designs.... but they are more hacks for the interested DIY that has a lot of electronic parts laying around.



However interesting the technology it seems not very fitting for mobile busses mainly based on the accumulated inefficiencies and having to rely on expensive and rare inverter technology.


Your lights are better served with DC, more efficient and reliable.
The extra money for micro inverters and expensive inverter is better spend in a dc refrigerator(IMHO).

The need to have that inverter running 24 Hrs a day at 60 watt stby losses adds up to 1440 Wh lost.. 1.44 kWh . If you have 3 clouded / rainy day then half of your battery capacity has disappeared.



In both our current busses I have used multiple lower cost MPPT and two cheap inverters... All for redundancy issues.. We cook with induction / microwave... shower with 120 VAC resistance heating. Having two cheaper inverters was a good redundacy policy because I blew one up on the road while I was trying to adjust it internals while attempting to run it beyond its 3.5Kw rating.



Nevertheless thanks again for the info. On our own house we have gridtie solar with battery backup.. 2x Outback gvfx3600 and 48 volt forklift doing double duty.


We are putting solar on three of our rental houses and the installers do not want anything to do with battery backup unless it is high tech.
We are more self reliance people so i want to be able to fix critical equipment and the high tech stuff does not fall in that category.... hence my experiments with the enphase 7.


Johan

[TomA]

Nothing to see here.

[joeblack5]

thanks TomA,
Solar needs to be promoted, just like electric cars. By my standards just the right thing to do.... financially it does not make a whole lot of sense... but most other investments are about taking money from the Devil anyhow.


Anyhow I am curious how your build will pann out.

[TomA]

Originally Posted by joeblack5

If your batteries are full then your solar shuts of, same with this micro inverter technology or straight DC technology.

That's not the mode I want. Then the load pulls through the battery until it falls to chargable status, the charger kicks in, restarts the array and we cycle like that depending on the hysteresis I program into the charge profile. I don't want all that charge cycling.

I want the array to stay up and be able to provide variable bypass AC to the load. I'm willing to put an artificially low CV value into the charge profile to keep the cycle operational, or even reduce the CC phase if that's more efficient, but sooner or later the charge cycle will end and I will want to go into charge bypass. If I can control the panels individually, I can prevent that by extending the charging cycle to where the array is up almost all the day.

60 watts doesn't seem so horrible to me, but you're right, its high. There would have to be some very cloudy winter days not to keep up with a 5kw array, but your experience is valuable and worth mining: How many kWh do you use in 24 hours in your buses? I conservatively (over)estimated my worst case days in the hot summer with 18,000 btu of aircon, an apartment fridge, meat locker, electric kitchen, hot water, and 4 souls aboard with lots of electronics at 11-12kWh per day, now over 13 because I underestimated the standby inverter loss. Am I nuts on that? At my house we use about 9kWh in winter, about 20 in summer. Its hotter than Arizona here...

I hear what you're saying about the overall cost. Much as I'm loathe to do it, cheap inverters and MPPT controllers would solve the problem for less money, but its a hobby, too. I'm really enamored with shutting off power output at the panels, and that gear is easily road-hardened. Its the old accident reconstruction experience poking the hairs up on the back of my neck. I do not want hot DC pigtails snaking around my sharp-edged Faraday cage, or 20 fuses on the roof. Compromises, compromises...

[joeblack5]

Not sure i understand with....quote..That's not the mode I want...


your solar panels charging the batteries is a continues process. Like I said there is no difference from a power or operational perspective if you go thru microinverters or charge controllers and then a main inverter.


Only in the micro inverter case you still need the main large inverter to power your loads during sundown or rain.


Our Dory bus operates on 24V and is re-designed for 2 adults 2 kids and dog.

It has 16 pieces 20 year old 75 watt BP/Siemens panels.. separated in groups of four panels . Each group has its own MPPT. The panels have degraded to about 60 watts. A modern same size panel would be 100 watt.

We use a Dometic DC fridge with additional insulation and additional cooling fan on the condensor coil.

Separate 12V freezer box.

All lights are 24 DC LED.
Cooking are two induction plates. Microwave.. 700 watt..

24 Volt water pump with membrane pressure tank.
No running hot water in the kitchen
Shower is recirculating water with shower head heating 3500 watt.


Battery 2 pieces 8D lead acid that double as starting batteries.

Battery Voltage / Ah monitoring... panel voltage /Amp monitoring per group.

No AC...we have very large windows then open all the way...perfect for us.

TV/ computer screen 32" 19 Volt powered with dedicated 24V to 19V converter.
Several labtops.

Floor heating with webasto diesel TSL17



We lived out of this for 4 months. We did mind our use and it worked out fine.

In general in January in the South West of the USA our batteries were considered full at 1 PM.



I am estimating 2 KWh / day.... mainly cooking..
We cooked mostly around 4 PM when there was still sunlight as to have power for the night and starting in the morning.
We loved living with the weather and Sun.



Improvements.. converting from a double 8D battery, about 2.4 KWH, to a lithium 10KWH. Maybe 4 more panel and a small windmill.



Everybody has a hobby.. mine is efficiency and cheap.


Johan