I’m taking my air conditioning off the grid this summer — here’s how

[admin]

How I'm using renewable energy to save on electric utility costs this summer.

I’m taking my air conditioning off the grid this summer — here’s how : Read more

 

[TomXP411]

Hi, Mike

You'll want more panels than that. My primary station (which I use for my Work From Home setup) has 8KWh of battery and 1.2KW of panels. With that setup, my batteries will get about 4-5KWh of charge on a good day..

Your excess usage in the summer is about 200KWh, or 6.67KWh/day. So I think you sized the battery right, but the panels you have won't generate nearly enough power. You need to at least double that.

The biggest mistake everyone makes is under-paneling their system, assuming that the panels will put out the rated amount all day. In reality, the output is more like a sine wave, and you get about 4-5 watt-hours per watt of panel over the course of a day.

So those panels will give you around 3-4KWh on a good day and much less in cloudy weather.

So with 8KWh of battery, you need more like 2KW of panels to fully charge that battery in one day.

Finally - those foldable panels tend to not do even their rated output. You should really get some proper stationary panels, probably something like 250 watt bifacial panels with a vertical mount setup.

You can definitely cut back on the electric bill, but to do 100% will need about twice the generation of what you're going to get with those 400 watt portable panels.

 

[bhunter736 at YouTube]

Tom has offered a lot of great information. I think something key to your issue is simply that the panels will only produce at their peak when the sky is clear and the panels are fully perpendicular to to the sun. The energy fall off as the angle shifts is more than you might expect. Great to see an article like yours on Toms Guide. Every step someone takes in this direction is an overall benefit.

 

[TomXP411]

Every step someone takes in this direction is an overall benefit.

Thank you!

And I agree. I'd love to see every house out there with solar on the roof and batteries in the garage. The more power we can gather and store from the sun, the better it is for everyone! =)

 

[solarac]

Unfortunately Anker as well as other portable solar generator manufacturers use low cost, short lived, high frequency, transformerless inverter technology in their designs that offer poorer surge capacities and lack galvanic isolation which can not only shorten this inverter tech's life expectancy, but can also damage or can even set your AC unit on fire. If you want to safely power an AC unit long term, then you need to use a low frequency, transformer based inverter instead.

 

[MangoCat]

I have a smaller Anker battery+inverter, it's a nice piece of kit to power devices in parts of our (large) yard that don't have electric service.

However, pay attention to the battery cycle lifetime spec: ours says 3000 cycles. At that rate, even charging the battery "for free" from solar, the cost of replacing the battery every 3000 or so cycles will be higher per kWh than buying electricity from the grid at $0.12/kWh.

So, hopefully most of your air-conditioning power is coming directly from the solar panels, not being stored in and drawn from your battery system. The battery+inverter is a nice way to avoid "grid dependence" but it's not usually a money saver in the long run, unless grid prices for power inflate much faster than they have historically.