PV Window Box

[Jacob Petersheim]

I have already concluded that whole-house solar isn't practical for me here.

In the Summer I have to many leafed-out tall trees that shade most of my lot including my roof much of the day. Even areas that sunlight reaches directly part of the day end up shaded more than not. Winter is another story, offering even less power where sunlight reaches, and some of the large trees are evergreens so they remain obstacles. Not to mention we have more days of mostly cloudy and completely overcast in Winter.

Many who installed large-scale home solar power did so on the backs of tax credits which discounted the initial costs and selling power back into the grid to offset some of the operating costs such as maintenance and updates.

Solar panels need sweeping and washing and snow removal, not to mention cleaning out nests of wasps and crap left from Spring bird nesting. PV panels also degrade with time, becoming less efficient due to heat and aging and eventual surface erosion. Batteries don't last forever, though newer and more refined products are now good for as many as 4000 daily charge and discharge cycles before dropping to 80% of original capacity. Electronics (and there are a lot of electronic components orchestrating everything) can also fail.

Now...

It is becoming problematic getting credit for feeding your excess generated power out into the grid. Some power companies have long stopped accepting new backfeed applications, and have also begun charging grid transport fees on any outbound power.

In Europe this is beginning to get bad. Grid power fees are high and many had tried the "socially responsible" and economic path of whole-house PV. Changes such as grid-output transport fees are now making the payback time for a solar installation much longer. This appears to be driving some homeowners to stop sending power back into the grid. With the discouragement of coal, natural gas, and nuclear, the public grid has come to rely on capturing excess household solar though.

Austria wants to introduce a SOCIAL TARIFF for Electricity!

Her accent is a bit thick, so you might need to turn on closed captions for that video.

 

[Jacob Petersheim]

I now have my kitchen refrigerator completely time-shifted off the peak electricity rate hours here, and I even cover up to 6 off-peak hours with stored solar power. I also use solar to prefill the battery driving the fridge so that less grid power is used to recharge once peak rate time is over each day.

The next large load I'd like to eliminate peak-hours grid use for is my basement dehumidifier but the logistics are awkward if I want to supplement that with solar power. So instead I'll tackle something else first.

I'm finding that I am using my PC and dual monitors during peak billing hours. This burns from 130 to 165 watts depending on load and ambient temperature (and thus fan load). Small enough to be covered using one of my smaller powerstations, with no lugging "buckets" of captured solar power up and down stairs. I am close to doing this now.

And of course I am still powering interior lighting, small fans around the house, and keeping various things like my lawnmower, leaf blower, string trimmer, etc. charged and running.

None of this is paying for itself in peak rate savings or even solar-offset savings.

But... This is just a hobby activity. One that keeps my mind active, keeps me running outside, keeps me lifting weights and running cables, etc. It beats staring at the walls until I'm drooling on myself in a rest home. If I get a little return from the activity then it feels a little bit less frivolous.

Think of it like fishing or gardening or tapping trees to make maple syrup.

 

[Jacob Petersheim]

Many powerstations above a certain size support remote access via Bluetooth and/or WiFi. Over time newer products are offering this down into the 0.5KWh range.

These phone apps offer monitoring, control, and can display usage statistics. Here is an example for my Big Guy, other manufacterers offer similar functionality.


Here you can see the power flows and battery charge level. Here my refrigerator is taking 189 watts, passed through from the grid. In the meantime there are also 99 watts of solar power coming in and it is used to top off the battery. There are also options to prioritize PV input and feed it to the AC and/or DC loads in preference to the grid.

There are also charts of usage. inputs and outputs, giving hourly totals by day, month, or year. You can also remotely power the unit off when desired.

 

[Jacob Petersheim]

Here is a screenshot from another brand's app. It shows the "inputs" display, which is showing battery at 5% and 18 watts of solar input (the sunrise has not cleared the trees yet):


This one also shows the temperature of the device.

It doesn't have the powerflow graphic of the other make, but all of the data is available in another form.

 

[Jacob Petersheim]

After spending time every day with this gear I have decided that the best portable solar array for me is the 180 watt N-Type 16 busbar panel I bought.

Very light, very good performer. Downsides: (1.) relatively fragile so for transporting these you really want the carrying case they come with, and (2.) they have fold-out "kickstands" but these do not support the panels at the steep angles you want near to sunrise and sunset.

I "fix" this by pounding in a prop-rod (green plastic-coated garden support rod) at an angle and leaning the array against it at a high angle. later on in the day I can just use the built-in kickstands.

Most powerstations in the mid-capacity ranges (500 to 1000 watt-hours) can accept up to 60 volts of PV input at 8 to 10 amps. These ZOUPW 180W model panels have 17 volt output, so I can wire two in series for those powerstations. Or I can use just one and use it with a smaller powerstation, most accept up to 25 volts so it's all good.



When I got started at this I bought a powerstation + solar array bundle deal. This 350 watt array puts out 33 volts, so it can't be used with smaller powerstations. It is also many times heavier, bulkier, and awkward to set up and take down, and performs quite poorly in comparison with a pair of the N-Type 180 watt arrays. There are also other issues, such as the delamination at the folds - which I am now seeing myself.

 

[Jacob Petersheim]

I've checking things around the house, and small to medium fans I have use about 40 watts on high.

So even a smaller 280 watt-hour powerstation can run such a fan for 7 hours. Step up to something in the 550 watt-hour range and a full charge gets you two fans for 7 hours or runs one fan two days.

A lot of the USB-powered lamps I have can be run as low as 1 watt or less when dimmed down 2/3 of the way. So that hardly makes a blip in the fan run-time if you combine using the two things together.

A fan is no air conditioner, but it beats nothing in sweltering heat. My mid-sized box fan blows a nice breeze down on medium speed or even low, extending the run-time further.

So this is a practical use for power outages that you might really appreciate. You probably have flashlights and candles, but running a fan and recharging your phone can be welcome.


Keep in mind that you don't need any solar panels for this. These powertations can be precharged from the grid and recharged from the car cigarette lighter if need be. Many people will recharge from a small gasoline generator they already have, which can't safely be used indoors.