1800W Apartment Balcony Solar + Battery Microgrid that can power fridge

As promised, some shots of my solar (self-made) installation.

Running 4 - 5 years straight powering full home office and TV, vacuum cleaning.

2 x 180W solar panels = 360W system (0.36kW)

Drilling a hole in plexiglass: A method for getting the cable from the outside to the inside without the draft. The (american-style vertical sliding) window then closes on the plexiglass.

2400Wh (2.4kWh) Xantrex battery, controller and 1800W (1.8kW) inverter in action.

Total cost on installation date: $4,386.38

Best, Anonymous

Sunboxlabs’s take

This is a very heavy-duty system which can serve much bigger wattages than anything else on this site: It can make 3.6x as much energy with it’s panels, store 5.7x as much energy in it’s batteries, and give off the energy at 18x the rate than my little room kit. Impressive!

Also note that submitter has a very smart solution for getting his cable through his window and bridging the cold gap: making a hole in transparent plexiglass!

Finally, luckily the price has massively declined in the past few years: While 4 years ago the installer paid $4,386, it is now available for $2,064. See below for newly researched links.

The kit

Parts Cost on Amazon: $2,064.02

2x Solar Panel

Connecting Cable

2 x AGM Battery

Controller, Inverter

Financial Payback & Embodied Energy

How long until it saves me money? The reason this system is so simple is because it doesn’t tie in to your apartment’s behind-the-meter electrical grid. This means the system is clean and easy to install yourself, but it also doesn’t automatically feed into electrical heavyweights like your water heater, refrigerator and washer/dryer. This system is so powerful though that you can plug in these heavyweights (at least refrigerator) into it! A typical, non-energy saving fridge uses around 1kWh / day like this one, and all of this could be offloaded onto the system. That’s savings of $56 per year. You’d need to add more loads like washing machine and TV to it to fully utilize this system.

Financial payback period for balcony 360W system
System cost : $2064 on Amazon at time of writing
Yearly energy creation: 365d * 4.26hsun/d * 360W = 542’894Wh/y
Yearly value creation: 543kWh/y * 15.34c/kWh = $81/y energy created
System payback period: $2064 / $81 = 25 years until payback

The financial payback of the system is 25 years including battery, due to the relatively small solar panel system. The battery battery system is not the cheapest either, and energy in general is super cheap at currently 15.34c/kWh.

If the panels were on the rooftop, the math would be different:

Financial payback period for rooftop 360W system
System cost : $2064 on Amazon at time of writing
Yearly energy creation: 365d * 6.66hsun/d * 360W = 875,124Wh/y
Yearly value creation: 875kWh/y * 15.34c/kWh = $134/y energy created
System payback period: $2064 / $134 = 15.4 years until payback

Tech Specs

Solar Panels:
    2 x 180 watt solar panels
    = 360W total chargin power 

Charge controller:
    1 x Charge Controller

    2 x 6V 200 aH AGM Batteries
    = 2400 Wh of storage
    = 6.6 hours until fully charged (2400Wh / 360 W from panels)

    1 x 1800 watt inverter with battery case 

    1 - 80' Solar Connecting Cable; 
    1 - Base w/wheels          
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